Alibaba Singapore Holding Private Limited

Alibaba Innovation Private Limited

Alibaba Group Holding Limited

Jiachen Huang

Jianxin Chen

Dawei Ding

Fang Zhang

Systems and methods for performing iFRB benchmarking are disclosed. Exemplary systems can include a quantum component and a classical component. The classical component can include at least one processor and at least one non-transitory computer-readable medium. The non-transitory computer-readable medium can contain instructions that, when executed by the at least one processor, cause the classical component to perform operations. The operations can include generating a gate sequence including test gates interleaved with gate subsequences equivalent to Haar random two-qubit gates. Each gate subsequence can include at least one SQiSW gate. The operations can further include generating a recovery gate based on the gate sequence. The operations can further include providing commands applying the gate sequence and the recovery gate to the quantum component and obtaining an output from the quantum component.

Benchmarking protocol for quantum gates

Systems and methods are provided for implementing arbitrary single-qubit quantum gates using sequences of single-qubit quantum gates. The systems and methods can implement a first quantum gate in a gate sequence by applying a first sequence of phase-shifted pulses to the qubit. After applying the first quantum gate, a second quantum gate in the gate sequence can be implemented by applying a second sequence of phase-shifted pulses to the qubit. The implementation of the second quantum gate can introduce an additional rotation. This additional rotation can be independent of the implementation of the first quantum gate. A pulse in the second sequence can be configured to implement: a virtual Z gate having a first rotation angle; an X gate having a second rotation angle; and the virtual Z gate having a negative of the first rotation angle.

Implementing qubit gates using phase-shifted microwave pulses

Embodiments of the disclosure provide method for performing contraction on a tensor network. The method can include: receiving, by a system, a tensor network comprising a plurality of tensors and a plurality of edges among the plurality of tensors, wherein each edge is associated with a plurality of index elements; determining a contraction order of the tensor network; determining, among the plurality of edges, one or more edges for generating a plurality of sub-networks based on the tensor network; and distributing the plurality of sub-networks to a plurality of computing nodes of the system to perform, by the plurality of computing nodes, contraction on the plurality of sub-networks based on the contraction order.

Distributed tensor network contraction scheme with splitting based on dynamic ordering

Methods, apparatuses, and systems include: based on a parameter of a quantum gate, generating representations of mrandom unitary quantum gates; determining a representation of a first quantum-gate sequence equivalent to an identity operator; determining a representation of a second quantum-gate sequence equivalent to the identity operator; sending, to a quantum computing device, hardware instructions corresponding to the representation of the first quantum-gate sequence the second quantum-gate sequence; receiving a first number of measurements of a qubit after applying the first quantum-gate sequence to the qubit for the first number of times by the quantum computing device and a second number of measurements of the qubit after applying the second quantum-gate sequence to the qubit for the second number of times by the quantum computing device; and determining a fidelity value of the quantum gate based on a first probability and a second probability.

Methods and systems of fully-randomized benchmarking for quantum circuits

Methods, apparatuses, and systems include: based on a parameter of a quantum gate, generating representations of mi random unitary quantum gates; determining a representation of a first quantum-gate sequence equivalent to an identity operator; determining a representation of a second quantum-gate sequence equivalent to the identity operator; sending, to a quantum computing device, hardware instructions corresponding to the representation of the first quantum-gate sequence the second quantum-gate sequence; receiving a first number of measurements of a qubit after applying the first quantum-gate sequence to the qubit for the first number of times by the quantum computing device and a second number of measurements of the qubit after applying the second quantum-gate sequence to the qubit for the second number of times by the quantum computing device; and determining a fidelity value of the quantum gate based on a first probability and a second probability.

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San Mateo, CA, United States of America

Jiachen Huang