Research On Verifiable Blind Quantum Computing

Quantum computation has drawn intense interests in recent years due to a growing trend of quantum supremacy.However,scalable quantum compution is still hard to achieve.Quantum computing is likely to be implemented in the cloud model in the near future,since only a few organizations own quantum computers.Blind quantum computing provides such a cloud scheme,where a client with only abilities to do classical computing and prepare or measure single qubits can delegate her computation tasks to a server who has ability to do universal quantum computation while simultaneously keeping the input,output,and algorithm unknown to the server.Based on this,verifiable blind quantum computation protocols are proposed to verify the correctness of computation outcome.In this paper,we focus on the verifiability and resource overhead of verifiable blind quantum computing.1.We present a novel construction for the resource state of verifiable blind quantum computation.The scenario of verification that we consider is the interaction between a client with capability of single-qubit preparation and a server.We use sandglass-like graph state as the resource state of verifiable blind quantum computation.This approach achieves a better verifiability of 0.866 in the case of classical output.In addition,the number of required qubits is2N+4cN,where N and c are the number of vertices and the maximal degree in the original computation graph,respectively.In other words,our overhead is less linear in the size of the computational scale.Finally,we utilize the method of repetition and fault-tolerant code to optimise the verifiability.2.We present parallel self-testing for device-independent verifiable blind quantum computation.The scenario of verification that we consider is the interaction between a fully classical client and two non-communicating server that share entanglement.We present a parallel self-testing technology to extract the presence of tensor products of Pauli observables on maximally entangled state.We then design non-local games to propose a device-independent verification protocol.Compared with other existing protocols,our scheme has a lower overhead,which costs O(n¹¹log n) Bell pairs,where n is the size of original computation.3.We propose verification of blind quantum computation with entanglement witnesses.The scenario of verification that we consider is the interaction between a client that performs single-qubit measurements and a server.We utilize three entanglement witnesses to estimate the fidelity of the prepared graph state.Applying entanglement witnesses to design the testing stage,we propose new verification protocols.Our protocol requires an overhead in terms of copies of the graph state that scales as O(n²log n),where n is the number of qubits of the graph state.Furthermore,the soundness of our protocol is improved.