If quantum bits(qubits)couple to the Same environment,it has been found the qubits decohere coherently.An interesting result from this phenomenon is that,for a kind of input states,i.e.,the coherence-preserving states...If quantum bits(qubits)couple to the Same environment,it has been found the qubits decohere coherently.An interesting result from this phenomenon is that,for a kind of input states,i.e.,the coherence-preserving states,coherence of the qubits can be preserved perfectly in quantum memory.In this paper,we propose a feasible scheme to transform an arbitrary unknown input state to the corresponding coherence-preserving state.The transformed state undergoes no decoherence in the noisy memory and,after that,it can be transformed back into the original state with decoherence much reduced.This scheme involves the use of an analogy of the ideas of quantum teleportation.展开更多
Hopf insulators are intriguing three-dimensional topological insulators characterized by an integer topological invariant. They originate from the mathematical theory of Hopf fibration and epitomize the deep connectio...Hopf insulators are intriguing three-dimensional topological insulators characterized by an integer topological invariant. They originate from the mathematical theory of Hopf fibration and epitomize the deep connection between knot theory and topological phases of matter, which distinguishes them from other classes of topological insulators. Here, we implement a model Hamiltonian for Hopf insulators in a solid-state quantum simulator and report the first experimental observation of their topological properties, including nontrivial topological links associated with the Hopf fibration and the integer-valued topological invariant obtained from a direct tomographic measurement. Our observation of topological links and Hopf fibration in a quantum simulator opens the door to probe rich topological properties of Hopf insulators in experiments. The quantum simulation and probing methods are also applicable to the study of other intricate three-dimensional topological model Hamiltonians.展开更多
The past decade has seen substantial progress in the research of quantum computation,with the number of coherently controllable qubits quickly increasing to hundreds and the fidelity of elementary quantum operations g...The past decade has seen substantial progress in the research of quantum computation,with the number of coherently controllable qubits quickly increasing to hundreds and the fidelity of elementary quantum operations going above the quantum error correction threshold.Among the various physical platforms for quantum computation,ion trap has the advantages of high-fidelity state preparation,measurement and gate operations[1].Besides,the long-range Coulomb interaction between the ions naturally enables strong connectivity of the qubits[2],which can significantly reduce the overhead in compiling quantum circuits.However,similar to other physical platforms,the currently available ion trap quantum computers are still far from the ultimate goal of solving universal and practical problems,which may require millions of high-fidelity qubits[3].展开更多
The optical fields in squeezed states are typical nonclassical fields.They play animportant role in many fields,such as the detection of very weak singles and the quantumnondemolition measurements.Squeezed states have...The optical fields in squeezed states are typical nonclassical fields.They play animportant role in many fields,such as the detection of very weak singles and the quantumnondemolition measurements.Squeezed states have been generated in experiment bymany nonlinear optical processes.Recently the probability of generating squeezed states bymass-varying or frequency-varying harmornic oscillators was discussed and under someapproximations the problem of these oscillators has been solved.In this note we展开更多
Quantum noise of optical solitons is analysed based on the exact solutions of the quantum nonlinear Schrodmger equation (QNSE) and the construction of the quantum soliton states. The noise limits are obtained for the ...Quantum noise of optical solitons is analysed based on the exact solutions of the quantum nonlinear Schrodmger equation (QNSE) and the construction of the quantum soliton states. The noise limits are obtained for the local photon number and for the local quadrature phase amplitude. They are larger than the vacuum fluctuation. So in the fundamental soliton states the variance of the local photon number and the local quadrature phase amplitude cannot be squeezed The sohton states with the minimum noise are quasi-coherent states, in which the quantum dispersion effects are negligible.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.69438010.
文摘If quantum bits(qubits)couple to the Same environment,it has been found the qubits decohere coherently.An interesting result from this phenomenon is that,for a kind of input states,i.e.,the coherence-preserving states,coherence of the qubits can be preserved perfectly in quantum memory.In this paper,we propose a feasible scheme to transform an arbitrary unknown input state to the corresponding coherence-preserving state.The transformed state undergoes no decoherence in the noisy memory and,after that,it can be transformed back into the original state with decoherence much reduced.This scheme involves the use of an analogy of the ideas of quantum teleportation.
基金supported by the grants from the Ministry of Science and Technology of Chinathe Ministry of Education+2 种基金support from the ARL and the AFOSR MURI programssupported by JQI-NSF-PFCLPS-MPO-CMTC
文摘Hopf insulators are intriguing three-dimensional topological insulators characterized by an integer topological invariant. They originate from the mathematical theory of Hopf fibration and epitomize the deep connection between knot theory and topological phases of matter, which distinguishes them from other classes of topological insulators. Here, we implement a model Hamiltonian for Hopf insulators in a solid-state quantum simulator and report the first experimental observation of their topological properties, including nontrivial topological links associated with the Hopf fibration and the integer-valued topological invariant obtained from a direct tomographic measurement. Our observation of topological links and Hopf fibration in a quantum simulator opens the door to probe rich topological properties of Hopf insulators in experiments. The quantum simulation and probing methods are also applicable to the study of other intricate three-dimensional topological model Hamiltonians.
基金supported by the Innovation Program for Quantum Science and Technology(2021ZD0301601)the New Cornerstone Science Foundation through the New Cornerstone Investigator Program+1 种基金the Ministry of Education of China,Tsinghua University Initiative Scientific Research ProgramTsinghua University Dushi program。
文摘The past decade has seen substantial progress in the research of quantum computation,with the number of coherently controllable qubits quickly increasing to hundreds and the fidelity of elementary quantum operations going above the quantum error correction threshold.Among the various physical platforms for quantum computation,ion trap has the advantages of high-fidelity state preparation,measurement and gate operations[1].Besides,the long-range Coulomb interaction between the ions naturally enables strong connectivity of the qubits[2],which can significantly reduce the overhead in compiling quantum circuits.However,similar to other physical platforms,the currently available ion trap quantum computers are still far from the ultimate goal of solving universal and practical problems,which may require millions of high-fidelity qubits[3].
基金supported by the National Natural Science Foundation of China.
文摘The optical fields in squeezed states are typical nonclassical fields.They play animportant role in many fields,such as the detection of very weak singles and the quantumnondemolition measurements.Squeezed states have been generated in experiment bymany nonlinear optical processes.Recently the probability of generating squeezed states bymass-varying or frequency-varying harmornic oscillators was discussed and under someapproximations the problem of these oscillators has been solved.In this note we
基金Project supported by the National Natural Science Foundation of China
文摘Quantum noise of optical solitons is analysed based on the exact solutions of the quantum nonlinear Schrodmger equation (QNSE) and the construction of the quantum soliton states. The noise limits are obtained for the local photon number and for the local quadrature phase amplitude. They are larger than the vacuum fluctuation. So in the fundamental soliton states the variance of the local photon number and the local quadrature phase amplitude cannot be squeezed The sohton states with the minimum noise are quasi-coherent states, in which the quantum dispersion effects are negligible.
