Article
Physics, Multidisciplinary
Hector Freytes, Giuseppe Sergioli
Summary: An extension of classical propositional logic is introduced in the framework of quantum computation with mixed states using the quantum Fredkin gate. This extension explores an expanded notion of classical contradiction within a holistic framework.
Article
Quantum Science & Technology
Wen-Wu Liu, Chun-Ling Zhang, Ling Zhang
Summary: In this paper, a one-step scheme to generate a CNOT gate via transitionless quantum driving is proposed, which exhibits robustness against instability related to variation in experimental parameters and decoherence. The scheme can be extended to generate a Toffoli gate for large-scale quantum computers, and its implementation is greatly simplified by involving only a single step.
QUANTUM INFORMATION PROCESSING
(2021)
Article
Physics, Multidisciplinary
Dylan Herman, Ruslan Shaydulin, Yue Sun, Shouvanik Chakrabarti, Shaohan Hu, Pierre Minssen, Arthur Rattew, Romina Yalovetzky, Marco Pistoia
Summary: This paper presents an approach that combines quantum Zeno dynamics with common quantum optimization algorithms (such as QAOA) to solve optimization problems with multiple arbitrary constraints on quantum computers. The authors introduce a technique that uses quantum Zeno dynamics to efficiently restrict the dynamics of quantum optimization to the in-constraint subspace on a fault-tolerant quantum computer, requiring only a small number of auxiliary qubits and no post-selection. They demonstrate the broad applicability of their technique by incorporating it into the quantum approximate optimization algorithm (QAOA) and variational quantum circuits for optimization. Numerical evaluations and a proof-of-concept demonstration on a quantum processor show the superiority of their method compared to state-of-the-art techniques in solving portfolio optimization problems with multiple realistic constraints.
COMMUNICATIONS PHYSICS
(2023)
Article
Optics
Fang-Fang Du, Gang Fan, Yi-Ming Wu
Summary: In this paper, a refined scheme for setting up a polarized Fredkin gate with the assistance of weak cross-Kerr nonlinearity, X-homodyne detectors, and linear optical elements is proposed. The scheme has a high success probability, feasibility with current technology, lower resource requirements, simplified circuits compared to existing proposals, and robustness against photon loss. It can be used for scalable quantum computation.
OPTICS COMMUNICATIONS
(2023)
Article
Quantum Science & Technology
Fang-Fang Du, Gang Fan, Yi-Ming Wu
Summary: In this paper, we propose two heralded schemes for implementing Toffoli and Fredkin gates simultaneously on polarization and spatial degrees of freedom (DoFs) of two-photon systems based on the photon-scattering property of a four-level emitter coupled to one-dimensional waveguide. Undesired scattering processes can be detected by the single-photon detectors. The fidelity of each gate is near to unit in principle under current technical conditions, ensuring the feasibility of the experiment. Moreover, the quantum circuits for the two gates are robust against decoherence and require less quantum resource compared with single DoF gates.
QUANTUM INFORMATION PROCESSING
(2023)
Article
Physics, Multidisciplinary
Quancheng Liu, Weijie Liu, Klaus Ziegler, Feng Chen
Summary: By conducting quantum analogy experiments in optical waveguide arrays, we have achieved and manipulated the Zeno effect and Zeno dynamics. This opens up new possibilities for realizing stroboscopic measurements in optics. We have successfully generated optical Zeno effect and optical Zeno dynamics by setting measurements in the strong regime, and demonstrated their relationship in optics. In addition, we have proposed a novel quantum Zeno slicing approach to dynamically engineer the Hilbert space of the monitored system.
PHYSICAL REVIEW LETTERS
(2023)
Article
Optics
Francesco Giacosa, Giuseppe Pagliara
Summary: The Leggett-Garg inequalities are applied to classical and quantum unstable systems. For classical systems, where the assumptions of macroscopic realism and noninvasive measurements hold, K-3 equals 1; for quantum systems, K-3 equals 1 only for purely exponential decays, while deviations from the exponential decay law predicted by quantum mechanics lead to values of K-3 not equal to 1.
Article
Optics
Hai-Chao Li, Wei Xiong, Guo-Qin Ge, M. Suhail Zubairy
Summary: This paper demonstrates competitive Zeno physics in the dissipative Jaynes-Cummings model. The study shows that the Zeno suppression of coherent evolution predicted by the standard model can fail dramatically in the presence of a dissipative environment. For hydrogen atom, such Zeno effect is usually not observable.
Article
Optics
Javier Contreras Sanchez, Fray de Landa Castillo-Alvarado, Jose Luis Hernandez-Pozos
Summary: We propose a scheme based on Bloch equations and Zeno-type measurements to control the probability density evolution of V-type system eigenstates. Numerical solutions of the equations demonstrate how the population in each level can be controlled using different sequences of pulse measurements. The evaluation of entropy between the measurement device and the field used for measurement indicates that entropy is maximized in the Zeno regime. These findings reveal various strategies for controlling the population levels of a V-type system, which can be implemented in trapped ions or NMR qubits, for example.
Article
Physics, Multidisciplinary
Meng Xu, J. T. Stockburger, G. Kurizki, J. Ankerhold
Summary: This study analyzes a minimal model of a quantum thermal machine, in which a driven two-level working medium is embedded in an environment with a spectrum possessing bandgaps. By using approximate and exact treatments, the researchers characterize this thermal machine in the deep quantum domain. They find that the spectral response and power output of the machine exhibit different features for different modulation rates, with fast modulation leading to power boost of strictly quantum origin and enhanced spectral reservoir response.
NEW JOURNAL OF PHYSICS
(2022)
Article
Physics, Multidisciplinary
Ye Cao, Jing Zhou
Summary: The study of the polaron of an open quantum system is important for verifying the effectiveness of many-body theory and predicting novel quantum phenomena. In this work, the molecular state and spectrum functions of polarons in different dissipation ranges and loss rates are determined through analytical research. The results show how the molecular and polaron states respond to increasing dissipation range.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2022)
Article
Multidisciplinary Sciences
Veysel Bayrakci, Fatih Ozaydin
Summary: This article proposes an entanglement swapping protocol based on quantum Zeno effect, which achieves almost unit fidelity with simple frequent threshold measurements and single particle rotations. The protocol can be extended to a series of repeater stations to construct quantum Zeno repeaters, which also achieve almost unit fidelity regardless of the number of repeaters, reducing the quantum circuit complexity of quantum repeaters.
SCIENTIFIC REPORTS
(2022)
Article
Physics, Multidisciplinary
Jin-Lei Wu, Yan Wang, Jin-Xuan Han, Shi-Lei Su, Yan Xia, Yongyuan Jiang, Jie Song
Summary: A dynamics regime of Rydberg atoms called unselective ground-state blockade (UGSB) is proposed to implement a one-step SWAP gate without individual addressing of atoms in the context of Rydberg antiblockade (RAB). This work modifies the RAB condition to achieve a dynamical and robust SWAP gate, and further investigates the implementation of a three-atom Fredkin gate based on the proposed SWAP gates.
FRONTIERS OF PHYSICS
(2022)
Article
Quantum Science & Technology
Ying-Li Liu, Yan-Qiang Ji, Xue Han, Wen-Xue Cui, Shou Zhang, Hong-Fu Wang
Summary: In this study, a scheme is proposed using quantum Zeno dynamics and shortcuts to adiabaticity for fast conversion of three-particle symmetric Dicke states |D-3((k))> to four-particle symmetric Dicke states |D-4((k))) with Rydberg superatoms. This scheme can be completed in one step by adjusting the Rabi frequencies of classical fields. The effect of decoherence induced by atomic spontaneous emission and cavity leakage on fidelities are also considered. Numerical simulations show that this scheme has high fidelities and robustness against decoherence.
ADVANCED QUANTUM TECHNOLOGIES
(2023)
Article
Optics
Lorenzo Rosso, Alberto Biella, Jacopo De Nardis, Leonardo Mazza
Summary: We investigate an interacting one-dimensional gas of spin-1/2 fermions with two-body losses and find a wide quantum Zeno region in the dynamical phase diagram. The Zeno region is characterized by the peculiar behavior of the lowest eigenvalues of a non-Hermitian Hamiltonian. By effectively decoupling the charge and spin degrees of freedom, we analyze the universal dynamics of this Zeno regime using an approximation scheme based on a non-Hermitian Heisenberg Hamiltonian for the spin. Our results show the buildup of peculiar charge properties in time, as witnessed by the momentum distribution function.
