We propose an efficient scheme to implement a multiplex-controlled phase gate with mul-tiple photonic qubits simultaneously controlling one target photonic qubit based on cir-cuit quantum electrodynamics(QED).For convenience,we denote this multiqubit gate as MCP gate.The gate is realized by using a two-level coupler to couple multiple cavities.The coupler here is a superconducting qubit.This scheme is simple because the gate im-plementation requires only one step of operation.In addition,this scheme is quite general because the two logic states of each photonic qubit can be encoded with a vacuum state and an arbitrary non-vacuum state|φ)(e.g.,a Fock state,a superposition of Fock states,a cat state,or a coherent state,etc.)which is orthogonal or quasi-orthogonal to the vacuum state.The scheme has some additional advantages:because only two levels of the cou-pler are used,i.e.,no auxiliary levels are utilized,decoherence from higher energy levels of the coupler is avoided;the gate operation time does not depend on the number of qubits;and the gate is implemented deterministically because no measurement is applied.As an example,we numerically analyze the circuit-QED based experimental feasibility of imple-menting a three-qubit MCP gate with photonic qubits each encoded via a vacuum state and a cat state.The scheme can be applied to accomplish the same task in a wide range of physical system,which consists of multiple microwave or optical cavities coupled to a two-level coupler such as a natural or artificial atom.

Qi-Ping Su;Yu Zhang;Liang Bin;Chui-Ping Yang

School of Physics,Hangzhou Normal University,Hangzhou 311121,China;School of Physics,Nanjing University,Nanjing 210093,China;Quantum Information Research Center,Shangrao Normal University,Shangrao 334001,China

物理学前沿

[1]Qi-Ping Su;Yu Zhang;Liang Bin;Chui-Ping Yang-.Efficient scheme for realizing a multi pl ex-control led phase gate with photonic qubits in circuit quantum electrodynamics)[J].物理学前沿,2022(05):119-129

multiqubit

Efficient,scheme,realizing,phase,gate,photonic,qubits,circuit,quantum,electrodynamics,We,propose,efficient,multiplex,controlled,simultaneously,controlling,one,target,QED,For,convenience,we,denote,this,MCP,realized,by,using,two,coupler,cavities,superconducting,This,simple,because,plementation,requires,only,step,operation,In,quite,general,logic,states,each,can,encoded,vacuum,arbitrary,Fock,superposition,cat,coherent,etc,which,orthogonal,quasi,some,additional,advantages,levels,are,used,auxiliary,utilized,decoherence,from,higher,energy,avoided,does,depend,number,implemented,deterministically,measurement,applied,example,numerically,analyze,experimental,feasibility,menting,three,via,accomplish,same,task,wide,range,physical,system,consists,microwave,optical,coupled,such,natural,artificial,atom

0.432588