CN109389223B - General quantum computer central processing unit and operation method thereof - Google Patents
General quantum computer central processing unit and operation method thereof Download PDFInfo
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Abstract
The embodiment of the invention discloses a general quantum computer central processing unit and an operation method thereof, which comprises the steps of preparing each quantum bit to an initial state by adjusting the external magnetic flux of each quantum bit contained in all basic units and the gate voltage of each quantum bit, and realizing that the coupling among the quantum bits is initially 0; selecting a current qubit coupling mode; according to the selected current qubit operation mode, determining a single qubit to be manipulated or two or more qubits to be coupled and communicated, and performing external magnetic flux adjustment, gate voltage adjustment and microwave pulse action, or performing combined adjustment of external magnetic flux and gate voltage on all qubits; the next operation is selected and the specific manipulations of the qubits are determined. The invention can solve the preparation of all the initial states of the qubits in the central processing unit, the operation of any single qubit, the coupling and parallel coupling operation between any two qubits and between multiple qubits, and has higher fidelity.
Description
Technical Field
The invention relates to the technical field of quantum computers, in particular to a general quantum computer central processing unit and an operation method thereof.
Background
The quantum computer has incomparable advantages compared with the classical computer in specific problems of large-scale factor decomposition, quantum simulation and the like, thereby having good application prospect. The core of the quantum computer is a central processing unit, and the execution of various quantum gate operations of single quantum bits and multiple quantum bits all need to be completed by the central processing unit. The coupling operation between any qubits of the central processor is particularly difficult in the operation of various qubits.
At present, the way of realizing the coupling operation between any quantum bits of the central processing unit to a certain extent is mainly realized by using various cavities as quantum buses. However, the coupling achieved by this method may have two coupling modes, namely capacitive (or inductive) coupling between qubits and coupling between qubits through a cavity quantum bus, and once the number of qubits is large, the two coupling modes may act together, so that the interaction between qubits is very disordered, and further, the operation of quantum computation is very difficult. Therefore, to effectively realize the coupling operation between arbitrary qubits, a single coupling mode should be adopted.
On the other hand, in the system of superconducting charge qubits, the most effective coupling mode between qubits is direct coupling via a capacitor, so that a single coupling mode of coupling between arbitrary qubits via a capacitor can be realized by directly connecting the capacitor to a point via a wire. In order to achieve almost perfect capacitive coupling between qubits, the inductance between the coupling capacitors must be sufficiently small, which requires a change in the wire connection between the coupling capacitors.
This is often achieved by a spin-wave approximation, since the coupling between the qubit in the idle state and the qubit being operated must be disconnected when all qubits in the central processor are directly connected via capacitors. Since, by approximation, there must be residual interactions, and a large number of residual interactions will affect the fidelity of the quantum gate operation. In order to minimize the residual interaction, the frequency difference between qubits and the coupling strength need to satisfy the higher requirement of the spin-wave approximation, so that when the number of qubits is large, frequency crowding occurs, making it difficult to increase the number of qubits in the central processing unit. Therefore, the problem needs to be solved to create a central processing unit with a large number of qubits.
For superconducting charge qubits, large capacitors are usually connected in parallel to reduce the charge energy while obtaining a larger effective josephson energy, so that the effective josephson energy of the qubits is much larger than the charge energy to obtain a long coherence time. This requires that when any single-qubit and multi-qubit operation is performed, the effective josephson energy of the qubit cannot be too small and always should be at least 50 times greater than its charge energy, while the range of variation of the effective josephson energy of the qubit is limited (thus resulting in a very limited range of frequency variation), and in order to avoid frequency crowding when applying the spin-wave approximation in the case of a large number of qubits, appropriate single-qubit and multi-qubit manipulation means must be employed.
Disclosure of Invention
The embodiment of the invention aims to provide a general quantum computer central processing unit and an operation method thereof, which can solve the problems of preparation of initial states of all quantum bits, operation of any single quantum bit, coupling operation between any two quantum bits, parallel coupling operation between multiple quantum bits, parallel operation of coupling between multiple pairs of two quantum bits, parallel operation of coupling between multiple groups of multiple quantum bits, parallel operation of coupling between one pair of two quantum bits and coupling between one group of multiple quantum bits, parallel operation of coupling between multiple pairs of two quantum bits and coupling between multiple groups of multiple quantum bits in the central processing unit, and the fidelity of quantum states obtained by coupling is higher.
In order to solve the above technical problem, an embodiment of the present invention provides a general-purpose quantum computer central processing unit, which includes a plurality of basic units each formed by a qubit and a coupling capacitor connected to the qubit, and all the basic units are connected to a same low-inductance body-shaped conductor through the coupling capacitors corresponding to the basic units.
Wherein the low-inductance bulk conductor is a superconductor below a critical temperature.
Wherein the qubit is one of a superconducting charge qubit, a transmon qubit, and an Xmon qubit.
The embodiment of the invention also provides a method for operating the central processing unit of the general quantum computer, which is realized on the central processing unit of the general quantum computer, and the method comprises the following steps:
step S1, preparing each qubit to an initial state by adjusting the external magnetic flux of each qubit contained in all basic units and the gate voltage of each qubit, and realizing that the coupling between each qubit is initially 0;
step S2, selecting the current quantum bit operation mode; the qubit operation modes comprise any single qubit manipulation mode, any pair of coupling modes between two qubits, any group of parallel coupling modes between multiple qubits, multiple pairs of parallel coupling modes between two qubits, multiple groups of parallel coupling modes between multiple qubits, parallel operation modes of coupling between a pair of qubits and coupling between a group of multiple qubits, and parallel operation modes of coupling between multiple pairs of two qubits and coupling between multiple groups of multiple qubits;
step S3, according to the selected current qubit operation mode, determining the single qubit to be manipulated or the two or more qubits to be coupled and communicated, and respectively performing corresponding external magnetic flux adjustment, gate voltage adjustment and microwave pulse action on the qubits to be manipulated or coupled and communicated, or performing combined adjustment of external magnetic flux and gate voltage on all the qubits;
step S4, selecting the next operation, and determining the specific operation of each quantum bit according to the selected current operation; wherein the next step of operation comprises: and continuing the next coupling operation, performing single-quantum bit manipulation, and jointly measuring the quantum state result obtained after a series of operations.
Wherein, the step S1 specifically includes:
adjusting the external magnetic flux of each qubit in all basic units to make the effective Josephson energy of any two qubits and the coupling energy of the two qubits meet | EJi±EJj|＞＞Eij(ii) a Wherein E isJiAn effective josephson energy for the ith qubit; eJjAn effective josephson energy for the jth qubit; eijCoupling energy formed between the ith qubit and the jth qubit;
regulating the environment temperature of the CPU to a low temperature state below the superconducting critical temperature to enable EJi＞＞kBT，kBBoltzmann constant, T is the thermodynamic temperature of the processor environment;
adjusting the gate voltage of each qubit such that the gate voltage of each qubit is satisfied
After a sufficient period of time, each qubit in the processor relaxes to an initial ground state; wherein, CgiThe capacitance value of the gate capacitor correspondingly connected with the ith quantum bit is a fixed value; vgiIs the ith quantityA gate voltage of the sub-bit; cRiIs the effective capacitance between the input of the resonator readout device and the ith qubit superconducting island; vRiA gate voltage provided to a resonant cavity readout; cXiIs the capacitance between the microwave XY control line and the ith qubit superconducting island; vXiA gate voltage provided for the microwave control line;
the external magnetic flux of each qubit is kept so that the effective Josephson energy of any two qubits and the coupling energy of the two qubits can both satisfy | EJi±EJj|＞＞Eij。
Wherein, the step S3 specifically includes:
when the selected current qubit operation mode is any single qubit manipulation mode, determining a qubit i to be operated;
jointly adjusting the external magnetic flux of each qubit to enable the difference between the effective Josephson energy of the qubit i and the other qubits to be far larger than the coupling energy between the qubits and the other qubits, specifically: the difference between the effective Josephson energy of qubit i and the effective Josephson energy of other qubits is not less than 10 of the coupling energy between them3The difference of effective Josephson energy between the qubit from which the qubit is next operated for k operation times among other qubits and other qubits in the processor is not less than coupling energy between them
Times and more than 50 times the coupling energy; simultaneously, the gate voltage of each qubit is jointly adjusted, so that the gate voltage of each qubit is at a degenerate point, i.e.
j ═ 1,2, …, N; and applying microwave pulses to the qubits i by using the microwave XY control lines, and realizing any rotation operation on the single qubit i by adjusting the frequency, the amplitude, the pulse time and the pulse frequency of the microwaves.
Wherein, the step S3 further includes:
when the selected current qubit operation mode is a coupling mode between any pair of two qubits, determining the two qubits to be coupled and communicated;
regulating and maintaining the gate voltage of each qubit to satisfy
Jointly adjusting the external magnetic flux of each qubit so that the effective Josephson energy of a pair of qubits to be coupled and the coupling energy between the qubits satisfy EJi＝EJjAnd | EJi+EJj|＞103EijWhile making the difference between the effective Josephson energy of any one of the pair of qubits and the other qubits in the processor not less than 10 of the coupling energy between them3Multiple, while making the difference between the effective Josephson energy of the qubit at the next operation time k times and the other qubits in the processor not less than the coupling energy between them
Times and more than 50 times;
after a period of time required for the operation of the quantum gate, the operation between the pair of qubits can be completed
A quantum gate operation or a swap operation is commonly used.
Wherein, the step S3 further includes:
when the selected current qubit operation mode is a parallel coupling mode among any group of multi-qubits, determining multi-qubits to be coupled and communicated;
regulating and maintaining the gate voltage of each qubit to satisfy
Jointly adjusting the external magnetic flux of each qubit so that the effective Josephson energy of any pair of qubits in a group of qubits to be coupled and the coupling energy between the qubits satisfy EJi＝EJjAnd | EJi+EJj|＞103EijSimultaneously, the difference of effective Josephson energy between any one of the quantum bits and other quantum bits except the quantum bits is not less than 10 of coupling energy between the quantum bits3Multiple, while making the difference between the effective Josephson energy of the qubit at the next operated time of k times and the other qubits in the processor not less than the coupling energy between them
Times and more than 50 times;
after a period of time required for the continuous coupling operation, any two qubits in the set of qubits are performed
The quantum gate coupling operation is commonly used.
Wherein, the step S3 further includes:
when the selected current qubit operation mode is a parallel coupling mode between a plurality of pairs of two qubits, determining two qubits to be coupled and corresponding to each of the plurality of pairs;
regulating and maintaining the gate voltage of each qubit to satisfy
Jointly adjusting the external magnetic flux of each qubit to make the effective Josephson energy of any one pair of qubits in the pairs of qubits to be coupled and the coupling energy between the qubits meet EJi＝EJjAnd | EJi+EJj|＞103EijWhile the difference between the effective Josephson energy of any one of the pair of qubits and the other qubits in the processor is no less than 10 of the coupling energy between them3Multiple, while making the difference between the effective Josephson energy of the qubit at the next operated time of k times and the other qubits in the processor not less than the coupling energy between them
Times and more than 50 times;
after the quantum gate operation is continued for a period of time, the parallel operation between each pair of qubits in the selected multiple pairs of qubits can be completed
A quantum gate operation or a swap operation is commonly used.
Wherein, the step S3 further includes:
when the selected current qubit operation mode is a parallel coupling mode among a plurality of groups of qubits, determining respective corresponding qubits to be coupled and communicated in the plurality of groups;
regulating and maintaining the gate voltage of each qubit to satisfy
Jointly adjusting the external magnetic flux of each qubit to make the effective Josephson energy of any two qubits in any group of qubits in multiple groups of qubits to be coupled and the coupling energy between the qubits meet EJi＝EJjAnd | EJi+EJj|＞103EijAnd simultaneously, the difference between the effective Josephson energy of any one of the quantum bits and other quantum bits in the processor is not less than 10 of the coupling energy between the quantum bits3Multiple, while making the difference between the effective Josephson energy of the qubit at the next operated time of k times and the other qubits in the processor not less than the coupling energy between them
Times and more than 50 times;
after the quantum gate operation is continued for a period of time, the parallelism between any pair of qubits in each group of the selected multiple groups of qubits can be completed
General purpose quantum gate operation without inter-qubit groupingA coupling operation is performed.
Wherein, the step S3 further includes:
when the selected current qubit operation mode is a parallel operation mode of coupling between a pair of two qubits and coupling between a group of multi-qubits, determining the qubits to be coupled and communicated respectively corresponding to the pair of two qubits and the group of multi-qubits;
regulating and maintaining the gate voltage of each qubit to satisfy
Jointly adjusting the external magnetic flux of each qubit to ensure that the effective Josephson energy of a pair of two qubits to be coupled and the coupling energy between the two qubits meet EJi＝EJjAnd | EJi+EJj|＞103EijSimultaneously enabling the effective Josephson energy of any two qubits in a group of multi-qubits to be coupled and the coupling energy between the two qubits to meet EJi＝EJjAnd | EJi+EJj|＞103EijSimultaneously, the difference between the effective Josephson energy of any one of the two qubits and the other qubits except the two qubits in the pair in the processor is not less than 10 of the coupling energy between the two qubits3Multiple, and simultaneously making the difference between the effective Josephson energy of any one of the group of qubits and the other qubits except the group of qubits in the processor not less than 10 of the coupling energy between the two qubits3Multiple, while making the difference between the effective Josephson energy of the qubit at the next operated time of k times and the other qubits in the processor not less than the coupling energy between them
Times and more than 50 times;
after the quantum gate operation is continued for a period of time, the selected pair of two qubits and the selected group of multiple qubits can be paralleled
The general quantum gate operates without a coupling operation being performed between the selected pair of two qubits and the selected set of multi-qubits.
Wherein, the step S3 further includes:
when the selected current qubit operation mode is a parallel operation mode of coupling between a plurality of pairs of two qubits and coupling between a plurality of groups of multi-qubits, determining the qubits to be coupled and communicated respectively corresponding to the plurality of pairs of two qubits and the plurality of groups of multi-qubits;
regulating and maintaining the gate voltage of each qubit to satisfy
Jointly adjusting the external magnetic flux of each qubit to ensure that the effective Josephson energy of any one of the two qubits to be coupled and the coupling energy between the two qubits meet the requirement of EJi＝EJjAnd | EJi+EJj|＞103EijSimultaneously enabling the effective Josephson energy of any two qubits in any one group of multi-qubits to be coupled and the coupling energy between the two qubits to meet EJi＝EJjAnd | EJi+EJj|＞103EijSimultaneously, the difference between the effective Josephson energy of any one qubit in any one selected pair of the two qubits and the effective Josephson energy of other qubits except the pair of the qubits in the processor is not less than 10 of the coupling energy between the qubits3And the effective Josephson energy difference between any one qubit in any one group of the selected multiple groups of multi-qubits and other qubits except the group of qubits in the processor is not less than 10 of the coupling energy between the qubits3Multiple, while making the difference between the effective Josephson energy of the qubit at the next operated time of k times and the other qubits in the processor not less than the coupling energy between them
Times and more than 50 times;
after the quantum gate operation is continued for a period of time, the parallelism between any one pair of the selected multiple pairs of two qubits and any one pair of the selected multiple groups of any one pair of qubits can be completed
The general quantum gate operates without coupling operations being performed between selected pairs of two qubits and selected different pairs of sets of multiple qubits, between different sets, and between different pairs and different sets.
Wherein, the step S4 further specifically includes:
and when the selected current qubit operation mode is to continue the next coupling operation or to perform single-qubit manipulation, returning to step S2 to continue the operation.
Wherein, the step S4 further includes:
when the selected current qubit operation mode is a result of jointly measuring the quantum state obtained after a series of operations, if the time required by the measurement is far shorter than the time required by the coupling operation, directly carrying out the joint measurement on each qubit; otherwise, the external magnetic flux of each qubit is adjusted in a combined manner, so that the difference between the Josephson energies of any two qubits is larger than the coupling energy between the qubits as much as possible, and then the qubits are measured in a combined manner.
The embodiment of the invention has the following beneficial effects:
1. the invention realizes the operation of the universal entangled quantum gate directly coupled by the capacitor between any quantum bits, and the coupling strength between the quantum bits can be designed freely as required only by changing the capacitance of the coupling capacitor, thereby obtaining the universal quantum computer with the optimal coupling strength;
2. the bulk superconducting conductor is directly connected with the coupling capacitor, so that the inductance between the coupling capacitors can be reduced to the minimum, the qubits are closer to a pure capacitive coupling high-efficiency and single coupling mode, and the condition that the two coupling modes of capacitive (or inductive) coupling and cavity coupling are crossed at the same time due to the fact that the coupling is realized by taking a cavity equivalent quantum bus as a medium is avoided, so that the quantum gate is simple and convenient to operate, high in efficiency and smaller in decoherence, and further has higher fidelity and longer decoherence time;
3. the scheme of the invention treats the quantum bits which are operating and will be operated after different time differently, and the frequency difference meets different conditions, thereby greatly reducing the frequency congestion, and leading the central processing unit to have more quantum bits under the working environment meeting the spin wave approximate condition;
4. the single-quantum bit operation is realized by a microwave XY control line, and the coupling between the quantum bits is realized by adjusting the external magnetic flux of each quantum bit, so that the scheme can better ensure that the effective Josephson energy of each quantum bit is far greater than the charge energy thereof in the operation process, thereby ensuring that the single-quantum bit operation has longer decoherence time and less quantum noise; the gate voltage of each qubit is controlled at or near the degenerate point, thus effectively eliminating the residual harmful rotation which is not needed for each qubit in the operation process and being beneficial to improving the decoherence time of each qubit;
5. the invention can effectively realize various operations required by general quantum computation, such as preparation of initial states of all the quantum bits in a central processing unit, operation of any single quantum bit, coupling operation between any two quantum bits, parallel coupling operation between multiple quantum bits, parallel operation of coupling between multiple pairs of two quantum bits, parallel operation of coupling between multiple groups of multiple quantum bits, parallel operation of coupling between a pair of two quantum bits and coupling between a group of multiple quantum bits, parallel operation of coupling between multiple pairs of two quantum bits and coupling between multiple groups of multiple quantum bits, and the like, thereby realizing the real general quantum computation.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is within the scope of the present invention for those skilled in the art to obtain other drawings based on the drawings without inventive exercise.
FIG. 1 is a schematic diagram of a connection structure of a CPU of a quantum computer according to an embodiment of the present invention;
fig. 2 is a flowchart of a method for operating a cpu of a quantum computer according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In order to find a general-purpose quantum computer central processing unit scheme which not only has an optimal coupling mode with high fidelity, but also can realize the coupling operation between any two quantum bits and the parallel coupling operation between multiple quantum bits, the inventor designs the central processing unit to take one quantum bit and a coupling capacitor correspondingly connected with the quantum bit as a basic unit, and all the basic units are directly connected with the same connecting structure of a low-inductance bulk conductor (a superconductor below the critical temperature) through the corresponding coupling capacitors, that is, as shown in fig. 1, one end of a series of capacitors is directly a same low-inductance bulk conductor (superconductor at the critical temperature), the other end of each capacitor is directly connected with a qubit, any qubit and any qubit can be directly coupled through a capacitor. In fig. 1, since the common inductance of the same low-inductance bulk conductor (superconductor below the critical temperature) is very small, so that the coupling between qubits caused by the LC harmonic oscillator is very small and can be approximately ignored, based on the above circuit structure, the inventor designs a method for jointly controlling the gate voltage and the external magnetic flux of each qubit to realize the disconnection and connection of the coupling between any qubits. The method can switch on the coupling between the qubits needing coupling operation, can switch on the coupling between the qubits in each group of a plurality of groups of qubits needing parallel coupling operation and switch off the coupling between the qubits in different groups, and can switch off the coupling between the qubits needing no coupling operation and all other qubits except the qubits, so that the qubits are in an idle state and do not influence all other qubits.
As can be seen from FIG. 1, there are N qubits Q1，Q2，...，QNThe Josephson junction capacitance of each qubit is C1，C2，...，CNEffective Josephson energy of each qubit is EJ1，EJ2，...，EJNEach qubit being coupled to a respective coupling capacitor Cm1，Cm2，...,CmNConnected and drive power respectively passes through the gate capacitors Cg1，Cg2，...，CgNDriving each qubit and providing a gate voltage Vg1，Vg2，...，VgNThe voltage on each qubit Josephson junction is respectively denoted as V1，V2，...,VNThe external magnetic flux passing through each qubit is phie1，Φe2，...,ΦeN. The Hamiltonian of the N qubit system of FIG. 1 is:
wherein the content of the first and second substances,
is the electrostatic energy E of the ith qubitci，Eij＝4e2CmiCmj/βDiDj) Is the coupling energy E between qubits i and jij(in the formula, Di＝Ci+Cgi+Cmi+CBi+CRi+CXi，
)，
Is the phase difference of the ith qubit, which satisfies the josephson equation:
it should be noted that the qubit may be a superconducting charge qubit, or may be a transmon qubit or an Xmon qubit.
Truncating equation (1) to |0 in two Cooper logarithmic statesi>And |1i>The spanned subspace (Cooper satisfies the eigenequation for the state
To be provided with
Based on a particular value of the gate voltage ngi＝-(CgiVgi+CRiVRi+CXiVXi)/2e＝1/2When, formula (1) can be written as:
wherein the content of the first and second substances,
the Pauly operator for the ith qubit.
Conversion of the Hamiltonian of formula (2) to a value related to H0In the interaction mapping of (c). When the condition (a) | E is satisfiedJi±EJj|＞＞EijAt a spin wave approximation, the quantum ratioThe Hamiltonian of the interaction between the bits i, j is zero, i.e. the coupling between them is broken; when the condition (b) E is satisfiedJk+EJl＞＞EklAnd E isJk-EJlAt 0, the Hamiltonian of the interaction between qubits k, l under the spin-wave approximation is
This corresponds exactly to one
Two qubits are commonly used for quantum gate operation.
Therefore, when the external magnetic flux of each qubit is adjusted such that either the above condition (a) or the above condition (b) is satisfied between any two qubits, the hamilton of the system in the interaction plot is:
for qubits k, l, one is implemented
The time of two-quantum-bit general quantum gate operation is tau-pi/(4J)ij)。
Therefore, when the condition (a) is satisfied between qubits, the coupling between them is broken, and when the condition (b) is satisfied, the coupling between them is opened.
Note the effective Josephson energy E in formula (1)JiSatisfies the relation of formula (4), that is, the effective Josephson energy E of each qubit can be obtained by formula (4)Ji：
Wherein the content of the first and second substances,
is the single junction Josephson energy of the ith qubit (assuming that the two Josephson junctions of the qubit are identical), ΦeiIs the external magnetic flux, phi, of the ith qubit adjustment0Is a magnetic flux quantum, i is a positive integer.
It should be noted that in implementing the switching of two qubits, a spin-wave approximation is used. To satisfy the condition of the spin approximation well, it is necessary to have | ω |i-ωj|＞＞JijThis condition is met by a higher criterion, e.g. we require | ωi-ωj|～103JijHowever, when the number of quantum bits is large, such a requirement causes frequency congestion, and it is difficult to realize a general-purpose quantum computer with a large number of quantum bits. To better satisfy the spin-wave approximation requirement while effectively reducing frequency crowding, we make the | ω satisfied between the qubits being operated on and other qubitsi-ωj|～103JijThis higher requirement, and for those qubits that will not be operated after a time interval t-k τ (τ being the time of one quantum gate operation and k being the number of operations), we make it satisfy | ω with other qubitsi-ωjL is not less than 103JijK, while | ωi-ωj|＞50JijThis requirement is met. On the other hand, to make qubits longer in decoherence time and less in quantum noise requires a large ratio between the effective josephson energy and the charge energy, so we make EJi/Eci≥100。
The operation of single quantum bit is realized by microwave XY pulse line, and the arbitrary rotation operation of single quantum bit can be realized by adjusting the frequency, amplitude, pulse time and pulse times of microwave pulse. In order to reduce the rotation of other qubits caused by coupling when a single-bit quantum operation is performed on a qubit, we make the qubit and the other qubits satisfy | ωi-ωj|＞＞JijThe conditions of (1).
Therefore, as shown in fig. 2, the inventor proposes a method for operating a quantum circuit of a cpu of a quantum computer based on the quantum computer in fig. 1, in which the quantum circuit uses a qubit and a corresponding coupling capacitor as basic units, and all the basic units are directly connected to the same low-inductance bulk conductor through the corresponding coupling capacitors, and the method includes the following steps:
step S1, preparing each qubit to an initial state by adjusting the external magnetic flux of each qubit contained in all basic units and the gate voltage of each qubit, and realizing that the coupling between each qubit is initially 0;
step S2, selecting the current quantum bit operation mode; the qubit operation modes comprise any single qubit manipulation mode, any pair of coupling modes between two qubits, any group of parallel coupling modes between multiple qubits, multiple pairs of parallel coupling modes between two qubits, multiple groups of parallel coupling modes between multiple qubits, parallel operation modes of coupling between a pair of qubits and coupling between a group of multiple qubits, and parallel operation modes of coupling between multiple pairs of two qubits and coupling between multiple groups of multiple qubits;
step S3, according to the selected current qubit operation mode, determining the single qubit to be manipulated or the two or more qubits to be coupled and communicated, and respectively performing corresponding external magnetic flux adjustment, gate voltage adjustment and microwave pulse action on the qubits to be manipulated or coupled and communicated, or performing combined adjustment of external magnetic flux and gate voltage on all the qubits;
step S4, selecting the next operation, and determining the specific operation of each quantum bit according to the selected current operation; wherein the next step of operation comprises: and continuing the next coupling operation, performing single-quantum bit manipulation, and jointly measuring the quantum state result obtained after a series of operations.
In step S1, the external magnetic flux of each qubit in all basic units is adjusted to make the effective Joseph of any two qubitsThe coupling energy of the Fursen energy and the two can both satisfy | EJi±EJj|＞＞Eij(ii) a Wherein E isJiAn effective josephson energy for the ith qubit; eJjAn effective josephson energy for the jth qubit; eijCoupling energy formed between the ith qubit and the jth qubit;
regulating the environment temperature of the CPU to a low temperature state below the superconducting critical temperature to enable EJi＞＞kBT，kBBoltzmann constant, T is the thermodynamic temperature of the processor environment;
adjusting the gate voltage of each qubit such that the gate voltage of each qubit is satisfied
After a sufficient period of time, each qubit in the processor relaxes to an initial ground state; wherein, CgiThe capacitance value of the gate capacitor correspondingly connected with the ith quantum bit is a fixed value; vgiA gate voltage of an ith qubit; cRiIs the effective capacitance between the input of the resonator readout device and the ith qubit superconducting island; vRiA gate voltage provided to a resonant cavity readout; cXiIs the capacitance between the microwave XY control line and the ith qubit superconducting island; vXiA gate voltage provided for the microwave control line;
the external magnetic flux of each qubit is kept so that the effective Josephson energy of any two qubits and the coupling energy of the two qubits can both satisfy | EJi±EJj|＞＞Eij。
In step S2, the qubit operation mode may be selected to realize coupling between nearest neighbor qubits and between arbitrary non-nearest qubits, and a parallel coupling operation of multiple pairs of qubits, a parallel coupling operation of multiple groups of qubits (each group having 3 or more qubits), and the like may be realized. The method specifically comprises the following steps: any single qubit manipulation, any pair of two qubits coupling, any group of multi-qubits parallel coupling, multi-pair two qubits parallel coupling, multi-group multi-qubits parallel coupling, coupling between a pair of two qubits and coupling between a group of multi-qubits, and multi-pair two qubits and multi-group multi-qubits coupling.
In step S3, according to the current qubit operation mode selected in step S2, the external magnetic flux adjustment, the gate voltage adjustment, and the microwave pulse action are respectively performed on the qubits to be manipulated or coupled and connected, or the combined adjustment of the external magnetic flux and the gate voltage is performed on all the qubits, where the specific operation mode is implemented as follows:
(1) when the selected current qubit operation mode is any single qubit manipulation mode, determining a qubit i to be operated;
jointly adjusting the external magnetic flux of each qubit to enable the difference between the effective Josephson energy of the qubit i and the other qubits to be far larger than the coupling energy between the qubits and the other qubits, specifically: the difference between the effective Josephson energy of qubit i and the effective Josephson energy of other qubits is not less than 10 of the coupling energy between them3The difference of effective Josephson energy between the qubit from which the qubit is next operated for k operation times among other qubits and other qubits in the processor is not less than coupling energy between them
Times and more than 50 times the coupling energy; simultaneously, the gate voltage of each qubit is jointly adjusted, so that the gate voltage of each qubit is at a degenerate point, i.e.
Microwave pulses are applied to the qubit i by using a microwave XY control line, and the arbitrary rotation operation of a single qubit i can be realized by adjusting the microwave frequency, the microwave amplitude, the pulse time and the microwave frequency.
(2) When the selected current qubit operation mode is a coupling mode between any pair of two qubits, determining the two qubits to be coupled and communicated;
regulating and maintaining the respective quantitiesSub-bit gate voltage satisfy
Jointly adjusting the external magnetic flux of each qubit so that the effective Josephson energy of a pair of qubits to be coupled and the coupling energy between the qubits satisfy EJi＝EJjAnd | EJi+EJj|＞103EijWhile making the difference between the effective Josephson energy of any one of the pair of qubits and the other qubits in the processor not less than 10 of the coupling energy between them3Multiple, while making the difference between the effective Josephson energy of the qubit at the next operated time of k times and the other qubits in the processor not less than the coupling energy between them
Times and more than 50 times;
after a period of time required for the operation of the quantum gate, the operation between the pair of qubits can be completed
A quantum gate operation or a swap operation is commonly used.
(3) When the selected current qubit operation mode is a parallel coupling mode among any group of multi-qubits, determining multi-qubits to be coupled and communicated;
regulating and maintaining the gate voltage of each qubit to satisfy
Jointly adjusting the external magnetic flux of each qubit so that the effective Josephson energy of any pair of qubits in a group of qubits to be coupled and the coupling energy between the qubits satisfy EJi＝EJjAnd | EJi+EJj|＞103EijSimultaneously, the difference of effective Josephson energy between any one of the quantum bits and other quantum bits except the quantum bits is not less than 10 of coupling energy between the quantum bits3Multiple, while enabling the distance to be operated next timeAnd the difference between the effective Josephson energy of the qubit with k times of operation time and the other qubits in the processor is not less than the coupling energy between them
Times and more than 50 times;
after a period of time required for the continuous coupling operation, any two qubits in the set of qubits are performed
The quantum gate coupling operation is commonly used.
(4) When the selected current qubit operation mode is a parallel coupling mode between a plurality of pairs of two qubits, determining two qubits to be coupled and corresponding to each of the plurality of pairs;
regulating and maintaining the gate voltage of each qubit to satisfy
Jointly adjusting the external magnetic flux of each qubit to ensure that the effective Josephson energy of any pair of qubits in a plurality of pairs of qubits to be coupled and the coupling energy between the qubits meet EJi＝EJjAnd | EJi+EJj|＞103EijWhile the difference between the effective Josephson energy of any one of the pair of qubits and the other qubits in the processor is no less than 10 of the coupling energy between them3Multiple, while making the difference between the effective Josephson energy of the qubit at the next operated time of k times and the other qubits in the processor not less than the coupling energy between them
Times and more than 50 times;
after the quantum gate operation is continued for a period of time, the parallel operation between each pair of qubits in the selected multiple pairs of qubits can be completed
A quantum gate operation or a swap operation is commonly used.
(5) When the selected current qubit operation mode is a parallel coupling mode among a plurality of groups of qubits, determining respective corresponding qubits to be coupled and communicated in the plurality of groups;
regulating and maintaining the gate voltage of each qubit to satisfy
Jointly adjusting the external magnetic flux of each qubit to make the effective Josephson energy of any two qubits in any group of qubits in multiple groups of qubits to be coupled and the coupling energy between the qubits meet EJi＝EJjAnd | EJi+EJj|＞103EijAnd simultaneously, the difference between the effective Josephson energy of any one of the quantum bits and other quantum bits in the processor is not less than 10 of the coupling energy between the quantum bits3Multiple, while making the difference between the effective Josephson energy of the qubit at the next operated time of k times and the other qubits in the processor not less than the coupling energy between them
Times and more than 50 times;
after the quantum gate operation is continued for a period of time, the parallelism between any pair of qubits in each group of the selected multiple groups of qubits can be completed
The general quantum gate operates without coupling operations being performed between different groups of qubits.
(5) When the selected current qubit operation mode is a parallel operation mode of coupling between a pair of two qubits and coupling between a group of multi-qubits, determining the qubits to be coupled and communicated respectively corresponding to the pair of two qubits and the group of multi-qubits;
regulating and maintaining the gate voltage of each qubit to satisfy
Jointly adjusting the external magnetic flux of each qubit to ensure that the effective Josephson energy of a pair of two qubits to be coupled and the coupling energy between the two qubits meet EJi＝EJjAnd | EJi+EJj|＞103EijSimultaneously enabling the effective Josephson energy of any two qubits in a group of multi-qubits to be coupled and the coupling energy between the two qubits to meet EJi＝EJjAnd | EJi+EJj|＞103EijSimultaneously, the difference between the effective Josephson energy of any one of the two qubits and the other qubits except the two qubits in the pair in the processor is not less than 10 of the coupling energy between the two qubits3Multiple, and simultaneously making the difference between the effective Josephson energy of any one of the group of qubits and the other qubits except the group of qubits in the processor not less than 10 of the coupling energy between the two qubits3Multiple, while making the difference between the effective Josephson energy of the qubit at the next operated time of k times and the other qubits in the processor not less than the coupling energy between them
Times and more than 50 times;
after the quantum gate operation is continued for a period of time, the selected pair of two qubits and the selected group of multiple qubits can be paralleled
The general quantum gate operates without a coupling operation being performed between the selected pair of two qubits and the selected set of multi-qubits.
(6) When the selected current qubit operation mode is a parallel operation mode of coupling between a plurality of pairs of two qubits and coupling between a plurality of groups of multi-qubits, determining the qubits to be coupled and communicated respectively corresponding to the plurality of pairs of two qubits and the plurality of groups of multi-qubits;
regulating and maintaining the gate voltage of each qubit to satisfy
Jointly adjusting the external magnetic flux of each qubit to ensure that the effective Josephson energy of any one of the two qubits to be coupled and the coupling energy between the two qubits meet the requirement of EJi＝EJjAnd | EJi+EJj|＞103EijSimultaneously enabling the effective Josephson energy of any two qubits in any one group of multi-qubits to be coupled and the coupling energy between the two qubits to meet EJi＝EJjAnd | EJi+EJj|＞103EijSimultaneously, the difference between the effective Josephson energy of any one qubit in any one selected pair of the two qubits and the effective Josephson energy of other qubits except the pair of the qubits in the processor is not less than 10 of the coupling energy between the qubits3And the effective Josephson energy difference between any one qubit in any one group of the selected multiple groups of multi-qubits and other qubits except the group of qubits in the processor is not less than 10 of the coupling energy between the qubits3Multiple, while making the difference between the effective Josephson energy of the qubit at the next operated time of k times and the other qubits in the processor not less than the coupling energy between them
Times and more than 50 times;
after the quantum gate operation is continued for a period of time, the parallelism between any one pair of the selected multiple pairs of two qubits and any one pair of the selected multiple groups of any one pair of qubits can be completed
A general quantum gate operation with selected pairs of two qubits and selected groups of multiple qubits between different pairs, different groups and noneNo coupling operation is performed between the same pair and the different groups.
It should be noted that the parallel operation in the various operations of step S3 is all for the case that the coupling energy between the qubits is the same; if the coupling energy among the qubits is different, when various parallel operations are executed, for the qubits which are firstly coupled, the difference of the effective Josephson energy of the qubits is far larger than the coupling energy among the qubits through the combined adjustment of external magnetic flux, so that the coupling action is timely disconnected just after the coupling operation among the qubits is finished.
In step S4, the specific operation mode is realized as follows:
(1) and when the selected current qubit operation mode is to continue the next coupling operation or to perform single-qubit manipulation, returning to step S2 to continue the operation.
(2) When the selected current qubit operation mode is a result of jointly measuring the quantum state obtained after a series of operations, if the time required by the measurement is far shorter than the time required by the coupling operation, directly carrying out the joint measurement on each qubit; otherwise, the external magnetic flux of each qubit is jointly adjusted, so that the difference between the Josephson energies of any two qubits is larger than the coupling energy between the qubits as much as possible, and then the qubits are jointly measured.
The embodiment of the invention has the following beneficial effects:
1. the invention realizes the general entangled quantum gate operation that any quantum bit is directly coupled by the capacitor, and the coupling strength between the quantum bits can be designed as required only by changing the capacitance of the coupling capacitor, thereby obtaining the general quantum computer with the optimal coupling strength;
2. the bulk superconducting conductor is directly connected with the coupling capacitor, so that the inductance between the coupling capacitors can be reduced to the minimum, the qubits are closer to a pure capacitive coupling high-efficiency and single coupling mode, and the condition that the two coupling modes of capacitive (or inductive) coupling and cavity coupling are crossed at the same time due to the fact that the coupling is realized by taking a cavity equivalent quantum bus as a medium is avoided, so that the quantum gate is simple and convenient to operate, high in efficiency and smaller in decoherence, and further has higher fidelity and longer decoherence time;
3. the scheme of the invention treats the quantum bits which are operating and will be operated after different time differently, and the frequency difference meets different conditions, thereby greatly reducing the frequency congestion, and leading the central processing unit to have more quantum bits under the working environment meeting the spin wave approximate condition;
4. the single-quantum bit operation is realized by a microwave XY control line, and the coupling between the quantum bits is realized by adjusting the external magnetic flux of each quantum bit, so that the scheme can better ensure that the effective Josephson energy of each quantum bit is far greater than the charge energy thereof in the operation process, thereby ensuring that the single-quantum bit operation has longer decoherence time and less quantum noise; the gate voltage of each qubit is controlled at or near the degenerate point, thus effectively eliminating the residual harmful rotation which is not needed for each qubit in the operation process and being beneficial to improving the decoherence time of each qubit;
5. the invention can effectively realize various operations required by general quantum computation, such as preparation of initial states of all quantum bits in a central processing unit, operation of any single quantum bit, coupling operation between any two quantum bits, parallel coupling operation between multiple quantum bits, parallel operation of coupling between multiple pairs of two quantum bits, parallel operation of coupling between multiple groups of multiple quantum bits, parallel operation of coupling between a pair of two quantum bits and coupling between a group of multiple quantum bits, parallel operation of coupling between multiple pairs of two quantum bits and coupling between multiple groups of multiple quantum bits, and the like, thereby realizing the real general quantum computation.
It will be understood by those skilled in the art that all or part of the steps in the method for implementing the above embodiments may be implemented by relevant hardware instructed by a program, and the program may be stored in a computer-readable storage medium, such as ROM/RAM, magnetic disk, optical disk, etc.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. A general quantum computer central processing unit control method is characterized in that the method is realized on a general quantum computer central processing unit, the general quantum computer central processing unit comprises a plurality of basic units formed by a quantum bit and coupling capacitors correspondingly connected with the quantum bit, and all the basic units are connected to the same low-inductance body-shaped conductor through the corresponding coupling capacitors; the low-inductance body conductor is a superconductor below the critical temperature; the method comprises the following steps:
step S1, preparing each qubit to an initial state by adjusting the external magnetic flux of each qubit contained in all basic units and the gate voltage of each qubit, and realizing that the coupling between each qubit is initially 0;
step S2, selecting the current quantum bit operation mode; the qubit operation modes comprise any single qubit manipulation mode, any pair of coupling modes between two qubits, any group of parallel coupling modes between multiple qubits, multiple pairs of parallel coupling modes between two qubits, multiple groups of parallel coupling modes between multiple qubits, parallel operation modes of coupling between a pair of qubits and coupling between a group of multiple qubits, and parallel operation modes of coupling between multiple pairs of two qubits and coupling between multiple groups of multiple qubits;
step S3, according to the selected current qubit operation mode, determining the single qubit to be manipulated or the two or more qubits to be coupled and communicated, and respectively performing corresponding external magnetic flux regulation, gate voltage regulation and microwave pulse action on the qubit to be manipulated or coupled and communicated, or performing combined regulation of external magnetic flux and gate voltage on all the qubits;
step S4, selecting the next operation, and determining the specific operation of each quantum bit according to the selected current operation; wherein the next step of operation comprises: continuing the next coupling operation, performing single-quantum bit manipulation, and jointly measuring the quantum state result obtained after a series of operations;
the step S3 specifically includes:
when the selected current qubit operation mode is any single qubit manipulation mode, determining a qubit i to be operated;
jointly adjusting the external magnetic flux of each qubit to enable the difference between the effective Josephson energy of the qubit i and the other qubits to be far larger than the coupling energy between the qubits and the other qubits, specifically: the difference between the effective Josephson energy of qubit i and the effective Josephson energy of other qubits is not less than 10 of the coupling energy between them3The difference of effective Josephson energy between the qubit from which the qubit is next operated for k operation times among other qubits and other qubits in the processor is not less than coupling energy between them
Times and more than 50 times the coupling energy; simultaneously, the gate voltage of each qubit is jointly adjusted, so that the gate voltage of each qubit is at a degenerate point, i.e.
And applying microwave pulses to the qubits i by using the microwave XY control lines, and realizing any rotation operation on the single qubit i by adjusting the frequency, the amplitude, the pulse time and the pulse frequency of the microwaves.
2. The general quantum computer central processing unit manipulation method of claim 1, wherein the step S1 specifically comprises:
adjusting the external magnetic flux of each qubit in all basic units to make the effective Josephson energy of any two qubits and the coupling energy of the two qubits meet | EJi±EJj|＞＞Eij(ii) a Wherein E isJiAn effective josephson energy for the ith qubit; eJjAn effective josephson energy for a jth qubit; eijCoupling energy formed between the ith qubit and the jth qubit;
regulating the environment temperature of the CPU to a low temperature state below the superconducting critical temperature to enable EJi＞＞kBT，kBBoltzmann constant, T is the thermodynamic temperature of the processor environment;
adjusting the gate voltage of each qubit such that the gate voltage of each qubit is satisfied
After a sufficient period of time, each qubit in the processor relaxes to an initial ground state; wherein, CgiThe capacitance value of the gate capacitor correspondingly connected with the ith quantum bit is a fixed value; vgiA gate voltage of an ith qubit; cRiIs the effective capacitance between the input of the resonator readout device and the ith qubit superconducting island; vRiA gate voltage provided to a resonant cavity readout; cXiCapacitance between the microwave XY control line and the ith quantum bit superconducting island; vXiA gate voltage provided for the microwave control line;
the external magnetic flux of each qubit is kept so that the effective Josephson energy of any two qubits and the coupling energy of the two qubits can both satisfy | EJi±EJj|＞＞Eij。
3. The method for manipulating a central processing unit of a general purpose quantum computer of claim 2, wherein the step S3 further comprises:
when the selected current qubit operation mode is a coupling mode between any pair of two qubits, determining the two qubits to be coupled and communicated;
regulating and maintaining the gate voltage of each qubit to satisfy
Regulating each amount in combinationThe external magnetic flux of the sub-bits enables the effective Josephson energy of a pair of qubits to be coupled and the coupling energy between the qubits to satisfy EJi＝EJjAnd | EJi+EJj|＞103EijWhile making the difference between the effective Josephson energy of any one of the pair of qubits and the other qubits in the processor not less than 10 of the coupling energy between them3Multiple, while making the difference between the effective Josephson energy of the qubit at the next operated time of k times and the other qubits in the processor not less than the coupling energy between them
Times and more than 50 times;
after a period of time required for the operation of the quantum gate, the operation between the pair of qubits can be completed
A quantum gate operation or a swap operation is commonly used.
4. The method for manipulating a central processing unit of a general purpose quantum computer of claim 2, wherein the step S3 further comprises:
when the selected current qubit operation mode is a parallel coupling mode among any group of multi-qubits, determining multi-qubits to be coupled and communicated;
regulating and maintaining the gate voltage of each qubit to satisfy
Jointly adjusting the external magnetic flux of each qubit so that the effective Josephson energy of any pair of qubits in a group of qubits to be coupled and the coupling energy between the qubits satisfy EJi＝EJjAnd | EJi+EJj|＞103EijSimultaneously, the difference of effective Josephson energy between any one of the group of qubits and other qubits except the group of qubits is not less thanCoupling energy between them 103Multiple, while making the difference between the effective Josephson energy of the qubit at the next operated time of k times and the other qubits in the processor not less than the coupling energy between them
Times and more than 50 times;
after a period of time required for the continuous coupling operation, any two qubits in the set of qubits are performed
The quantum gate coupling operation is commonly used.
5. The method for manipulating a central processing unit of a general purpose quantum computer of claim 2, wherein the step S3 further comprises:
when the selected current qubit operation mode is a parallel coupling mode between a plurality of pairs of two qubits, determining two qubits to be coupled and corresponding to each of the plurality of pairs;
regulating and maintaining the gate voltage of each qubit to satisfy
Jointly adjusting the external magnetic flux of each qubit to ensure that the effective Josephson energy of any pair of qubits in a plurality of pairs of qubits to be coupled and the coupling energy between the qubits meet EJi＝EJjAnd | EJi+EJj|＞103EijWhile the difference between the effective Josephson energy of any one of the pair of qubits and the other qubits in the processor is no less than 10 of the coupling energy between them3Multiple, while making the difference between the effective Josephson energy of the qubit at the next operated time of k times and the other qubits in the processor not less than the coupling energy between them
Times and more than 50 times;
after the quantum gate operation is continued for a period of time, the parallel operation between each pair of qubits in the selected multiple pairs of qubits can be completed
A quantum gate operation or a swap operation is commonly used.
6. The method for manipulating a central processing unit of a general purpose quantum computer of claim 2, wherein the step S3 further comprises:
when the selected current qubit operation mode is a parallel coupling mode among a plurality of groups of qubits, determining respective corresponding qubits to be coupled and communicated in the plurality of groups;
regulating and maintaining the gate voltage of each qubit to satisfy
Jointly adjusting the external magnetic flux of each qubit to make the effective Josephson energy of any two qubits in any group of qubits in multiple groups of qubits to be coupled and the coupling energy between the qubits meet EJi＝EJjAnd | EJi+EJj|＞103EijAnd simultaneously, the difference between the effective Josephson energy of any one of the quantum bits and other quantum bits in the processor is not less than 10 of the coupling energy between the quantum bits3Multiple, while making the difference between the effective Josephson energy of the qubit at the next operated time of k times and the other qubits in the processor not less than the coupling energy between them
Times and more than 50 times;
after the quantum gate operation is continued for a period of time, the parallelism between any pair of qubits in each group of the selected multiple groups of qubits can be completed
The general quantum gate operates without coupling operations being performed between different groups of qubits.
7. The method for manipulating a central processing unit of a general purpose quantum computer of claim 2, wherein the step S3 further comprises:
when the selected current qubit operation mode is a parallel operation mode of coupling between a pair of two qubits and coupling between a group of multi-qubits, determining the qubits to be coupled and communicated respectively corresponding to the pair of two qubits and the group of multi-qubits;
regulating and maintaining the gate voltage of each qubit to satisfy
Jointly adjusting the external magnetic flux of each qubit to ensure that the effective Josephson energy of a pair of two qubits to be coupled and the coupling energy between the two qubits meet EJi＝EJjAnd | EJi+EJj|＞103EijSimultaneously enabling the effective Josephson energy of any two qubits in a group of multi-qubits to be coupled and the coupling energy between the two qubits to meet EJi＝EJjAnd | EJi+EJj|＞103EijSimultaneously, the difference between the effective Josephson energy of any one of the two qubits and the other qubits except the two qubits in the pair in the processor is not less than 10 of the coupling energy between the two qubits3Multiple, and simultaneously making the difference between the effective Josephson energy of any one of the group of multi-quantum bits and the other quantum bits except the group of multi-quantum bits in the processor not less than 10 of the coupling energy between the effective Josephson energy and the other quantum bits3Multiple, while making the difference between the effective Josephson energy of the qubit at the next operated time of k times and the other qubits in the processor not less than the coupling energy between them
Times and more than 50 times;
after the quantum gate operation is continued for a period of time, the selected pair of two qubits and the selected group of multiple qubits can be paralleled
The general quantum gate operates without a coupling operation being performed between the selected pair of two qubits and the selected set of multi-qubits.
8. The method for manipulating a central processing unit of a general purpose quantum computer of claim 2, wherein the step S3 further comprises:
when the selected current qubit operation mode is a parallel operation mode of coupling between a plurality of pairs of two qubits and coupling between a plurality of groups of multi-qubits, determining the qubits to be coupled and communicated respectively corresponding to the plurality of pairs of two qubits and the plurality of groups of multi-qubits;
regulating and maintaining the gate voltage of each qubit to satisfy
Jointly adjusting the external magnetic flux of each qubit to ensure that the effective Josephson energy of any one of the two qubits to be coupled and the coupling energy between the two qubits meet the requirement of EJi＝EJjAnd | EJi+EJj|＞103EijSimultaneously enabling the effective Josephson energy of any two qubits in any one group of multi-qubits to be coupled and the coupling energy between the two qubits to meet EJi＝EJjAnd | EJi+EJj|＞103EijSimultaneously, the difference between the effective Josephson energy of any one qubit in any one of the selected pairs of two qubits and the effective Josephson energy of other qubits except the pair of qubits in the processor is not less thanCoupling energy between them 103And simultaneously enabling the difference of the effective Josephson energy between any one qubit in any one group of the selected multiple groups of multi-qubits and other qubits except the any one group of multi-qubits in the processor to be not less than 10 of the coupling energy between the qubits and the other qubits3Multiple, while making the difference between the effective Josephson energy of the qubit at the next operated time of k times and the other qubits in the processor not less than the coupling energy between them
Times and more than 50 times;
after a period of time required for the operation of the quantum gate, the parallelism between any one pair of the selected multiple pairs of two qubits and between any one pair of the selected multiple groups of qubits can be completed
The general quantum gate operates without coupling operations being performed between selected pairs of two qubits and selected different pairs of sets of multiple qubits, between different sets, and between different pairs and different sets.
9. The general quantum computer central processing unit manipulation method of claim 1, wherein the step S4 further specifically comprises:
and when the selected current qubit operation mode is to continue the next coupling operation or to perform single-qubit manipulation, returning to step S2 to continue the operation.
10. The method for manipulating a central processing unit of a general purpose quantum computer of claim 1, wherein the step S4 further comprises:
when the selected current qubit operation mode is a result of jointly measuring the quantum state obtained after a series of operations, if the time required by the measurement is far shorter than the time required by the coupling operation, directly carrying out the joint measurement on each qubit; otherwise, the external magnetic flux of each qubit is jointly adjusted, so that the difference between the Josephson energies of any two qubits is larger than the coupling energy between the qubits as much as possible, and then the qubits are jointly measured.
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