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公开(公告)号：US20210390442A1
公开(公告)日：2021-12-16
申请号：US16981606
申请日：2019-01-31
Applicant: Google LLC
Inventor： Yuezhen Niu , Vadim Smelyanskiy , Sergio Boixo Castrillo
Abstract: Methods, systems and apparatus for implementing a quantum gate on a quantum system comprising a second qubit coupled to a first qubit and a third qubit. In one aspect, a method includes evolving a state of the quantum system for a predetermined time, wherein during evolving: the ground and first excited state of the second qubit are separated by a first energy gap ω; the first and second excited state of the second qubit are separated by a second energy gap equal to a first multiple of ω minus qubit anharmoniticity−; the ground and first excited state of the first qubit and third qubit are separated by a third energy gap equal to ω−; and the first and second excited state of the first qubit and third qubit are separated by a fourth energy gap equal to the first multiple of the ω minus a second multiple of .
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公开(公告)号：US20210272001A1
公开(公告)日：2021-09-02
申请号：US16981075
申请日：2019-01-31
Applicant: Google LLC
Inventor： Vadim Smelyanskiy , Andre Petukhov , Rami Barends , Sergio Boixo Castrillo
IPC: G06N10/00
Abstract: Methods, systems and apparatus for implementing iSWAP quantum logic gates between a first qubit and a second qubit. In one aspect, a method includes implementing a cascade schedule that defines a trajectory of a detuning between a frequency of the first qubit and a frequency of the second qubit. Implementing the cascade schedule includes: during a first stage, adiabatically driving detuning between the frequency of the first qubit and the frequency of the second qubit through a first avoided crossing in a leakage channel; during a second stage, driving detuning between the frequency of the first qubit and the frequency of the second qubit through a second avoided crossing in a swap channel; during a third stage, evolving the first qubit and second qubit; during a fourth stage, implementing the second stage in reverse order; and during a fifth stage, implementing the first stage in reverse order.
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公开(公告)号：US11055627B2
公开(公告)日：2021-07-06
申请号：US16961388
申请日：2018-01-31
Applicant: Google LLC
Inventor： Yuezhen Niu , Hartmut Neven , Vadim Smelyanskiy , Sergio Boixo Castrillo
Abstract: Methods, systems, and apparatus for implementing a unitary quantum gate on one or more qubits. In one aspect, a method includes the actions designing a control pulse for the unitary quantum gate, comprising: defining a universal quantum control cost function, wherein the control cost function comprises a qubit leakage penalty term representing i) coherent qubit leakage, and ii) incoherent qubit leakage across all frequency components during a time dependent Hamiltonian evolution that realizes the unitary quantum gate; adjusting parameters of the time dependent Hamiltonian evolution to vary a control cost according to the control cost function such that leakage errors are reduced; generating the control pulse using the adjusted parameters; and applying the control pulse to the one or more qubits to implement the unitary quantum gate.
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公开(公告)号：US20250148343A1
公开(公告)日：2025-05-08
申请号：US18352555
申请日：2023-07-14
Applicant: Google LLC
Abstract: An enhanced matrix product state-based decoder is generated and employed to almost optimally detect and correct errors within a quantum computing and information processing system. The decoder takes as input a detector level error model that describes physical error channels and a set of error detections. This error model is improved using experimental data.
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公开(公告)号：US20250045613A1
公开(公告)日：2025-02-06
申请号：US18923184
申请日：2024-10-22
Applicant: Google LLC
Inventor： Yuezhen Niu , Hartmut Neven , Vadim Smelyanskiy , Sergio Boixo Castrillo
Abstract: Methods, systems, and apparatus for implementing a unitary quantum gate on one or more qubits. In one aspect, a method includes the actions designing a control pulse for the unitary quantum gate, comprising: defining a universal quantum control cost function, wherein the control cost function comprises a qubit leakage penalty term representing i) coherent qubit leakage, and ii) incoherent qubit leakage across all frequency components during a time dependent Hamiltonian evolution that realizes the unitary quantum gate; adjusting parameters of the time dependent Hamiltonian evolution to vary a control cost according to the control cost function such that leakage errors are reduced; generating the control pulse using the adjusted parameters; and applying the control pulse to the one or more qubits to implement the unitary quantum gate.
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Patent Agency Ranking
公开(公告)号：US12124922B2
公开(公告)日：2024-10-22
申请号：US17433445
申请日：2019-03-05
Applicant: Google LLC
Inventor： Vadim Smelyanskiy , Andre Petukhov , Rami Barends , Sergio Boixo Castrillo , Yu Chen
IPC: G06N10/00
CPC classification number: G06N10/00
Abstract: Methods, systems and apparatus for generating plunge schedules for implementing iSWAP quantum logic gates between a first qubit and a second qubit. In one aspect, a plunge schedule that defines a trajectory of a detuning between a frequency of the first qubit and a frequency of the second qubit includes, during a first stage, non-adiabatically driving detuning between the frequency of the first qubit and the frequency of the second qubit through a first avoided crossing in a leakage channel, during a second stage, driving detuning between the frequency of the first qubit and the frequency of the second qubit through a second avoided crossing in a swap channel. during a third stage, allowing the first qubit and the second qubit to freely evolve and interact, during a fourth stage, implementing the second stage in reverse order, and during a fifth stage, implementing the first stage in reverse order.
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公开(公告)号：US12015705B1
公开(公告)日：2024-06-18
申请号：US17221291
申请日：2021-04-02
Applicant: Google LLC
Inventor： Sergio Boixo Castrillo , Alan Kar-Lun Ho , Jimmy C. Chau
CPC classification number: H04L9/0869 , G06F7/58 , G06N10/00 , H04L9/0852
Abstract: Systems and methods for quantum random number generation are provided. In some implementations, a method can include obtaining data indicative of a quantum circuit used by the quantum random number generation system to generate a quantum entropy source for determining a random number. The quantum entropy source can include a plurality of output samples. Each output sample can be obtained by measuring an output of the quantum circuit. The method can include performing one or more simulations of the quantum circuit to obtain a simulated output distribution of the quantum circuit without access to data associated with the random number. The method can include providing data indicative of the simulated output distribution for use in a verification process for the quantum random number generation system. The verification process can determine the use of the quantum computing system in generation of the quantum entropy source.
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公开(公告)号：US11657315B2
公开(公告)日：2023-05-23
申请号：US17339276
申请日：2021-06-04
Applicant: Google LLC
Inventor： Yuezhen Niu , Hartmut Neven , Vadim Smelyanskiy , Sergio Boixo Castrillo
Abstract: Methods, systems, and apparatus for implementing a unitary quantum gate on one or more qubits. In one aspect, a method includes the actions designing a control pulse for the unitary quantum gate, comprising: defining a universal quantum control cost function, wherein the control cost function comprises a qubit leakage penalty term representing i) coherent qubit leakage, and ii) incoherent qubit leakage across all frequency components during a time dependent Hamiltonian evolution that realizes the unitary quantum gate; adjusting parameters of the time dependent Hamiltonian evolution to vary a control cost according to the control cost function such that leakage errors are reduced; generating the control pulse using the adjusted parameters; and applying the control pulse to the one or more qubits to implement the unitary quantum gate.
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公开(公告)号：US11556686B2
公开(公告)日：2023-01-17
申请号：US16754998
申请日：2017-12-18
Applicant: Google LLC
Inventor： Sergio Boixo Castrillo , Vadim Smelyanskiy
IPC: G06F30/3308 , G06N10/00 , G06F7/544
Abstract: Methods, systems and apparatus for simulating quantum circuits including multiple quantum logic gates. In one aspect, a method includes the actions of representing the multiple quantum logic gates as functions of one or more classical Boolean variables that define a undirected graphical model with each classical Boolean variable representing a vertex in the model and each function of respective classical Boolean variables representing a clique between vertices corresponding to the respective classical Boolean variables; representing the probability of obtaining a particular output bit string from the quantum circuit as a first sum of products of the functions; and calculating the probability of obtaining the particular output bit string from the quantum circuit by directly evaluating the sum of products of the functions. The calculated partition function is used to (i) calibrate, (ii) validate, or (iii) benchmark quantum computing hardware implementing a quantum circuit.
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公开(公告)号：US20220269973A1
公开(公告)日：2022-08-25
申请号：US17623177
申请日：2019-10-24
Applicant: Google LLC
Inventor： Julian Shaw Kelly , Zijun Chen , Sergio Boixo Castrillo
Abstract: Methods, systems and apparatus for measuring quantum state purity. In one aspect, a method for determining an average purity of multiple output quantum states, wherein the multiple output quantum states correspond to applications of respective random quantum circuits of a same circuit depth to a same initial quantum state, the method including: obtaining a plurality of data items, wherein each data item corresponds to a respective random quantum circuit of the same circuit depth and represents a probability that application of the respective random quantum circuit to the initial quantum state produces a respective measurement result; calculating a variance of a plurality of data items; determining a Porter-Thomas distribution having a dimension equal to a dimension of each output quantum state; and dividing the calculated variance by a variance of the Porter-Thomas distribution to determine the average purity.
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