Preparing quantum superposition states is a crucial step in realizing quantum algorithms,which demands substantial resources.In this paper,we propose a new method for preparing quantum uniform superposition states via...Preparing quantum superposition states is a crucial step in realizing quantum algorithms,which demands substantial resources.In this paper,we propose a new method for preparing quantum uniform superposition states via quantum measurement,and design the bitwise implementation circuit,which only contains Hadamard,CNOT,and π/8 phase gates.Compared to the Shukla–Vedula method,the number of quantum gates required by both methods scales the same,while,the new method offers stronger fault tolerance,and the ancillary qubits employed during the implementation process can be reused,making it more suitable for implementation on real quantum computers.As an application,we provide the circuit for Shor's discrete logarithm quantum algorithm,based on the new method,demonstrating its technical advantage for implementation of quantum algorithms.展开更多
We study the quantum dynamics of an impurity-doped Bose–Einstein condensate(BEC) system.We show how to generate the macroscopic quantum superposition states(MQSSs) of the BEC by the use of projective measurements on ...We study the quantum dynamics of an impurity-doped Bose–Einstein condensate(BEC) system.We show how to generate the macroscopic quantum superposition states(MQSSs) of the BEC by the use of projective measurements on impurity atoms. It is found that the nonclassicality of MQSSs can be manipulated by changing the number of the impurities and their interaction with the BEC. It is shown that the BEC matter-wave field exhibits a collapse and revival phenomenon which reveals the quantum nature of the BEC matter-wave field. We investigate the micro-macro entanglement between the impurities and the BEC, and find enhancement of the micro-macro entanglement induced by the initial quantum coherence of the impurity atoms.展开更多
Using the principles of quantum state superposition and entanglement,quantum computing has been proven to be able to tackle problems that are hard for state-of-the-art supercomputers.Thirty years ago,when Shor’s algo...Using the principles of quantum state superposition and entanglement,quantum computing has been proven to be able to tackle problems that are hard for state-of-the-art supercomputers.Thirty years ago,when Shor’s algorithm and Grover’s algorithm were proposed and proven to have great acceleration on solving some problems,including factoring and searching,quantum computing was only a beautiful scientific dream.Today,quantum computing is advancing at an incredible pace.Over 10 years ago,Devoret and Schoelkopf said something similar in their review1.展开更多
This paper proposes a method of generating multipartite entanglement through using d.c. superconducting quan- tum interference devices （SQUID） inside a standing wave cavity. In this scheme, the d.c. SQUID works in t...This paper proposes a method of generating multipartite entanglement through using d.c. superconducting quan- tum interference devices （SQUID） inside a standing wave cavity. In this scheme, the d.c. SQUID works in the charge region. It is shown that, a large number of important multipartite entangled states can be generated by a controllable interaction between a cavity field and qubits. It is even possible to produce entangled states involving different cavity modes based on the measurement of charge qubits states. After such superpositions states are created, the interaction can be switched off by the classical magnetic field through the SQUID, and there is no information transfer between the cavity field and the charge qubits.展开更多
The dynamic evolution of a multi-level atom in the three-dimensional photonic crystal under an applied magnetic field is investigated.By combining the Zeeman effect with the photonic band gap effect,the dynamic quantu...The dynamic evolution of a multi-level atom in the three-dimensional photonic crystal under an applied magnetic field is investigated.By combining the Zeeman effect with the photonic band gap effect,the dynamic quantum superposition states and steady quantum coherent trapping states of the atom can be flexibly controlled.This paves the way for coherent manipulation of quantum states in the solid-state system,which has important applications in quantum information processing.展开更多
基金supported by National Key Research and Development Program of China(Grant No.2020YFA0309702)the National Natural Science Foundation of China(Grant No.61502526)+1 种基金NSAF(Grant No.U2130205)the Natural Science Foundation of Henan Province,China(Grant Nos.202300410532 and 252300421818)。
文摘Preparing quantum superposition states is a crucial step in realizing quantum algorithms,which demands substantial resources.In this paper,we propose a new method for preparing quantum uniform superposition states via quantum measurement,and design the bitwise implementation circuit,which only contains Hadamard,CNOT,and π/8 phase gates.Compared to the Shukla–Vedula method,the number of quantum gates required by both methods scales the same,while,the new method offers stronger fault tolerance,and the ancillary qubits employed during the implementation process can be reused,making it more suitable for implementation on real quantum computers.As an application,we provide the circuit for Shor's discrete logarithm quantum algorithm,based on the new method,demonstrating its technical advantage for implementation of quantum algorithms.
基金supported by the National Natural Science Foundation of China under Grants No. 11775075No.1143011 and No. 11935006。
文摘We study the quantum dynamics of an impurity-doped Bose–Einstein condensate(BEC) system.We show how to generate the macroscopic quantum superposition states(MQSSs) of the BEC by the use of projective measurements on impurity atoms. It is found that the nonclassicality of MQSSs can be manipulated by changing the number of the impurities and their interaction with the BEC. It is shown that the BEC matter-wave field exhibits a collapse and revival phenomenon which reveals the quantum nature of the BEC matter-wave field. We investigate the micro-macro entanglement between the impurities and the BEC, and find enhancement of the micro-macro entanglement induced by the initial quantum coherence of the impurity atoms.
文摘Using the principles of quantum state superposition and entanglement,quantum computing has been proven to be able to tackle problems that are hard for state-of-the-art supercomputers.Thirty years ago,when Shor’s algorithm and Grover’s algorithm were proposed and proven to have great acceleration on solving some problems,including factoring and searching,quantum computing was only a beautiful scientific dream.Today,quantum computing is advancing at an incredible pace.Over 10 years ago,Devoret and Schoelkopf said something similar in their review1.
基金Project supported by Hunan Provincial Natural Science Foundation of China （Grant No 06jj50014）.
文摘This paper proposes a method of generating multipartite entanglement through using d.c. superconducting quan- tum interference devices （SQUID） inside a standing wave cavity. In this scheme, the d.c. SQUID works in the charge region. It is shown that, a large number of important multipartite entangled states can be generated by a controllable interaction between a cavity field and qubits. It is even possible to produce entangled states involving different cavity modes based on the measurement of charge qubits states. After such superpositions states are created, the interaction can be switched off by the classical magnetic field through the SQUID, and there is no information transfer between the cavity field and the charge qubits.
基金supported by the National Key Basic Research Special Foundation of China (Grant Nos. 2006CB921706 and 2010CB923200)the National Natural Science Foundation of China (Grant Nos. 10574160 and10725420)
文摘The dynamic evolution of a multi-level atom in the three-dimensional photonic crystal under an applied magnetic field is investigated.By combining the Zeeman effect with the photonic band gap effect,the dynamic quantum superposition states and steady quantum coherent trapping states of the atom can be flexibly controlled.This paves the way for coherent manipulation of quantum states in the solid-state system,which has important applications in quantum information processing.
