Article
Multidisciplinary Sciences
Onat Arisoy, Ozgur E. Mustecaplioglu
Summary: In this study, a few-qubit system is proposed as a compact quantum refrigerator to cool an interacting multi-qubit system. By using a spin-star model to prepare refrigerant qubits, a collisional route to thermalization can effectively cool the many-qubit system. The operation cost and cooling efficiency of a simple refrigeration cycle can be controlled by parameters such as the number of ancilla qubits and the qubit-qubit interaction strength, and bounds on achievable temperature are established.
SCIENTIFIC REPORTS
(2021)
Article
Physics, Multidisciplinary
Fazlollah Kazemi Hasanvand, Negar Naderi
Summary: The correlation dynamics of a non-interacting two-qubit system embedded in a qutrit environment with a constant magnetic field were investigated. It was found that the concurrence and discord can be controlled by adjusting the environment's degrees of freedom, coupling strength, and external magnetic field strength. Additionally, decoherence is inevitable, but total entanglement death can be avoided within certain parameter ranges.
EUROPEAN PHYSICAL JOURNAL PLUS
(2021)
Article
Optics
Qin-Qin Wang, Si-Jing Tao, Wei-Wei Pan, Zhe Chen, Geng Chen, Kai Sun, Jin-Shi Xu, Xiao-Ye Xu, Yong-Jian Han, Chuan-Feng Li, Guang-Can Guo
Summary: Identifying the general mechanics behind the equilibration of a complex isolated quantum system towards a state described by only a few parameters has been the focus of attention. In this study, the relaxation of the spin subsystem in an isolated spin-orbit coupling quantum system is experimentally investigated, and the underlying mechanism of generalized thermalization is experimentally verified for the first time.
LIGHT-SCIENCE & APPLICATIONS
(2022)
Article
Optics
Yan Li, Zhihong Ren
Summary: We study the performance of an N-qubit W superposition state in quantum metrology, and find that the phase sensitivity under noninteracting operation displays a crossover from the W state to the GHZ state for large-qubit cases. We also provide optimal measurement protocols for ideal metrology and analyze the effects of noise channels on the phase sensitivity. Additionally, we investigate the tunable phase sensitivity under interacting operation and find that the general Heisenberg limit is surpassed.
Article
Physics, Multidisciplinary
Tanmoy Bera, Sourav Majumder, Sudhir Kumar Sahu, Vibhor Singh
Summary: Researchers have demonstrated a hybrid device incorporating a superconducting transmon qubit and a mechanical resonator coupled using magnetic-flux. They showed a high vacuum electromechanical coupling rate and the enhancement of electromechanical coupling by tuning the qubit position, while observing specific interference features.
COMMUNICATIONS PHYSICS
(2021)
Article
Optics
Damian Wlodzynski, Tomasz Sowinski
Summary: It has been argued that one-dimensional systems of strongly interacting fermions of different mass undergo critical transitions between spatial orderings when external confinement adiabatically changes shape. When considering finite-time drivings, the dynamics are typically guided by the lowest eigenstates and can be understood through the generalized Landau-Zener mechanism. By adjusting driving parameters, it is possible to target the desired many-body state in a noninfinite time.
Article
Optics
Pavel Stransky, Pavel Cejnar, Radim Filip
Summary: In this study, a system of a single qubit interacting with a soft-mode bosonic field is analyzed, revealing a complex arrangement of quantum phase transitions in both the ground and excited states. The experimentally observable signature of some transitions is a dynamical stabilization of a fully factorized qubit-field state involving the field vacuum, particularly in the ultrastrong coupling regime. The degree of stabilization abruptly varies with interaction parameters and increases with the softness of the field mode, showing connections to various forms of excited-state quantum phase transitions.
Article
Physics, Multidisciplinary
Y. Akbari-Kourbolagh, Z. Pazhotan
Summary: This study investigates the dynamics of entanglement in a hybrid non-interacting qubit-qutrit system under the influence of classical noises. The results show that the system exhibits different dynamics of entanglement depending on the configuration of classical noises.
INTERNATIONAL JOURNAL OF THEORETICAL PHYSICS
(2022)
Article
Physics, Multidisciplinary
Edwige Carole Fosso, Fridolin Tchangnwa Nya, Lionel Tenemeza Kenfack, Martin Tchoffo
Summary: In this study, the dynamics of entanglement in a system of four non-interacting qubits driven by a classical phase noisy laser characterized by a classical random external field (CREF) were investigated. It was found that coupling qubits in a common environment is an effective strategy to shield the system from the detrimental impacts of decoherence induced by CREF, and GHZ-type states exhibit stronger dynamics compared to W-type states under CREF. Additionally, system robustness can be greatly improved by increasing the number of qubits in the system.
Article
Multidisciplinary Sciences
Abdel-Baset A. Mohamed, Eied M. Khalil, Afrah Y. AL-Rezami, Hichem Eleuch
Summary: In this study, a superconducting charge qubit interacting with a dissipative microwave cavity field is analyzed for the effects of qubit-cavity interaction, qubit-cavity detuning, and dissipation on Wigner distribution and its non-classicality. The research shows that the amplitudes and frequency of the Wigner distribution can be controlled by various parameters, including the phase space parameters, qubit-cavity interaction, detuning, and dissipation. Cavity dissipation reduces non-classicality, and this reduction can be accelerated by the detuning.
Article
Multidisciplinary Sciences
Naoto Shiraishi, Keiji Matsumoto
Summary: The study investigates the undecidability of thermalization phenomena in isolated quantum many-body systems, even in one-dimensional systems. By constructing a family of Hamiltonians encoding dynamics of a reversible universal Turing machine, it is shown that the fate of a relaxation process can dramatically change depending on whether the Turing machine halts. The result indicates the lack of a general theorem, algorithm, or systematic procedure for determining the presence of thermalization in any given Hamiltonian.
NATURE COMMUNICATIONS
(2021)
Article
Multidisciplinary Sciences
F. H. B. Somhorst, R. van der Meer, M. Correa Anguita, R. Schadow, H. J. Snijders, M. de Goede, B. Kassenberg, P. Venderbosch, C. Taballione, J. P. Epping, H. H. van den Vlekkert, J. Timmerhuis, J. F. F. Bulmer, J. Lugani, I. A. Walmsley, P. W. H. Pinkse, J. Eisert, N. Walk, J. J. Renema
Summary: This study demonstrates that in a unitarily evolving system, single-mode measurements can converge to a thermal state using photons in an integrated optical interferometer. The resolution to the paradox between unitary evolution and the second law of thermodynamics is the recognition that the global unitary evolution of a multi-partite quantum state causes local subsystems to evolve towards maximum-entropy states. The experiment utilizes a programmable integrated quantum photonic processor to manipulate quantum states and shows the potential of photonic devices for simulating non-Gaussian states.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Multidisciplinary
Lorcan O. Conlon, Falk Eilenberger, Ping Koy Lam, Syed M. Assad
Summary: The study introduces a protocol for using collective measurements to distinguish quantum states, which achieves a lower probability of error compared to non-entangling measurements. Experimental results demonstrate the effectiveness of this approach.
COMMUNICATIONS PHYSICS
(2023)
Article
Optics
Arkaprabha Ghosal, Debarshi Das, Subhashish Banerjee
Summary: In this research, the efficacy of quantum resources for quantum teleportation were studied by considering the preparation of a pure two-qubit state and its transmission through a quantum channel. It was found that certain quantum channels have different effects on the utility of quantum teleportation depending on whether the initial state is maximally entangled or nonmaximally entangled. Additionally, nonunital channels were shown to be more effective than unital channels in producing useful states for universal quantum teleportation from nonmaximally entangled pure states.
Article
Quantum Science & Technology
Oscar Perdomo, Vicente Leyton-Ortega, Alejandro Perdomo-Ortiz
Summary: The study explores the set of two-qubit pure states with real amplitudes and their geometrical representation on a three-dimensional sphere. Maximally entangled states form two perpendicular disjoint circles, while unentangled states are π/4 units away from maximally entangled states. States connected by local gates are equidistant to the pair of circles.
QUANTUM INFORMATION PROCESSING
(2021)
Article
Physics, Multidisciplinary
Jiaozi Wang, Barbara Dietz, Dario Rosa, Giuliano Benenti
Summary: We investigate the generation of entanglement in a two-body interacting system starting from a separable coherent state. By analyzing the system's classical dynamics, we find that the entanglement growth rate in the quasiclassical regime can be simply computed. This rate is determined by the Kolmogorov-Sinai entropy, indicating a connection between the generation of entanglement and classical complexity.
Article
Physics, Multidisciplinary
Gabriele Cenedese, Maria Bondani, Dario Rosa, Giuliano Benenti
Summary: Generating a large amount of entanglement is crucial for a quantum computer to achieve quantum advantage. This paper proposes an efficient method to generate pseudo-random quantum states with nearly maximal multipartite entanglement. The method is argued to be optimal and is used to evaluate actual superconducting (IBM's ibm_lagos) and ion trap (IonQ's Harmony) quantum processors. Despite the lower error rates of ibm_lagos in single-qubit and two-qubit operations, Harmony outperforms it due to its low error rate in state preparation and measurement as well as the all-to-all connectivity of qubits. The findings highlight the importance of qubits network architecture in generating highly entangled states.
Article
Physics, Multidisciplinary
Gabriele Cenedese, Giuliano Benenti, Maria Bondani
Summary: Characterizing and mitigating errors in current noisy intermediate-scale devices is crucial for enhancing the performance of future quantum hardware. Through full quantum process tomography of single qubits in an actual quantum processor with echo experiments, we investigated the significance of various noise mechanisms in quantum computation. Our results unveiled the dominant role of coherent errors and demonstrated the practical correction of such errors by introducing random single-qubit unitaries in the quantum circuit, leading to a notable increase in the reliability of quantum computations on real quantum hardware.
Article
Physics, Multidisciplinary
Federico Roccati, Archak Purkayastha, G. Massimo Palma, Francesco Ciccarello
Summary: We investigate the dynamics of correlations in a dissipative gain-loss system. By using a setup with two coupled oscillators, one subject to local gain, we can implement parity-time (PT) symmetry in a more realistic way. We find that quantum correlations are reduced while total correlations are enhanced. Furthermore, we observe different behaviors across an exceptional point (EP) outside the PT symmetric regime, indicating the relevance of PT symmetry in the long-time dynamics.
EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS
(2023)
Review
Physics, Multidisciplinary
Giuliano Benenti, Davide Donadio, Stefano Lepri, Roberto Livi
Summary: Energy transfer in small nano-sized systems can be very different from that in their macroscopic counterparts due to reduced dimensionality, interaction with surfaces, disorder, and large fluctuations. We provide an overview of recent advances in understanding non-diffusive heat transfer in these systems through nonequilibrium statistical mechanics and atomistic simulations. The underlying basic properties leading to violations of standard diffusive heat transport and the effects of long-range interaction and integrability on non-diffusive transport are discussed. We also explore the applications of these features in thermal management, rectification, and improving energy conversion efficiency.
RIVISTA DEL NUOVO CIMENTO
(2023)
Article
Quantum Science & Technology
Gabriele Lo Monaco, Luca Innocenti, Dario Cilluffo, Dario A. Chisholm, Salvatore Lorenzo, G. Massimo Palma
Summary: Quantum information scrambling (QIS), which is the local non-retrievability of information evolved through dynamic processes, is often quantified using entropic quantities such as the tripartite information. However, this approach has some issues due to its reliance on quantum mutual informations that do not accurately quantify correlations retrievable via measurements, as well as the specific methodology used to compute the tripartite information. By using accessible mutual informations and defining corresponding 'accessible tripartite informations', these issues can be overcome. Our findings lay the groundwork for a deeper understanding of QIS and open up new avenues for further research.
QUANTUM SCIENCE AND TECHNOLOGY
(2023)
Article
Physics, Multidisciplinary
L. Innocenti, S. Lorenzo, I. Palmisano, A. Ferraro, M. Paternostro, G. M. Palma
Summary: Quantum machine learning applies machine learning concepts and techniques to quantum devices. This paper presents a framework to model quantum extreme learning machines (QELMs), demonstrating that they can be described concisely through single effective measurements and characterizing the information retrievable using such protocols. Understanding the capabilities and limitations of QELMs will enable their full deployment in system identification, device performance optimization, and state or process reconstruction.
COMMUNICATIONS PHYSICS
(2023)
Article
Multidisciplinary Sciences
Fabio Cavaliere, Luca Razzoli, Matteo Carrega, Giuliano Benenti, Maura Sassetti
Summary: This work investigates the performance of hybrid thermal machines that can simultaneously perform multiple tasks. Optimal working conditions for a three-terminal quantum thermal machine are characterized and identified, with the working medium being a quantum harmonic oscillator coupled to three heat baths. The study demonstrates efficient operation in both pure and hybrid modes, with the ability to switch between different operational modes by adjusting the driving frequency. The proposed setup also shows potential as a high-performance transistor.
Article
Physics, Multidisciplinary
Luca Razzoli, Fabio Cavaliere, Matteo Carrega, Maura Sassetti, Giuliano Benenti
Summary: In the pursuit of high-performance quantum thermal machines, considering fluctuations at the quantum level is crucial in addition to finding optimal thermodynamic efficiency. This paper investigates the thermodynamic uncertainty relations for a quantum thermal machine with a quantum harmonic oscillator as the working medium, connected to two thermal baths, with one of them being dynamically coupled. The study demonstrates that by adjusting parameters, the machine can function as both a quantum engine and refrigerator, achieving significant efficiency and low fluctuations.
EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS
(2023)
Article
Quantum Science & Technology
Dario A. Chisholm, Luca Innocenti, G. Massimo Palma
Summary: This paper points out that redundancy and consensus are different in the context of quantum objectivity, quantifying different features of the quantum-to-classical transition. The two main frameworks used to measure quantum objectivity, spectrum broadcast structure and quantum Darwinism, are best suited to quantify redundancy and consensus, respectively. By analyzing explicit examples, the paper highlights the potentially stark difference between the degrees of redundancy and consensus, causing a break in the hierarchical relations between spectrum broadcast structure and quantum Darwinism. The framework provided in this paper offers a new perspective to interpret known and future results in the context of quantum objectivity, paving the way for a deeper understanding of the emergence of classicality from the quantum realm.
Article
Materials Science, Multidisciplinary
Ilia Khomchenko, Henni Ouerdane, Giuliano Benenti
Summary: The control of thermal fluxes in electronic circuits at mesoscale and nanoscale can be achieved using thermal diodes. This study proposes using a superconductor-insulator-superconductor (SIS) junction under an oscillating voltage to control the heat flow. Theoretical models suggest a sharp rise in the rectification coefficient, up to R approximate to 500.
Article
Physics, Fluids & Plasmas
Giuliano Benenti, Giulio Casati, Fabio Marchesoni, Jiao Wang
Summary: A dynamical model of a highly efficient heat engine is proposed, where an applied temperature difference maintains the motion of particles around a circuit consisting of two asymmetric narrow channels, in one of which the current flows against the applied thermodynamic forces. Numerical simulations and linear-response analysis suggest that, in the absence of frictional losses, the Carnot efficiency can be achieved in the thermodynamic limit.
Article
Physics, Multidisciplinary
L. Giannelli, J. Rajendran, N. Macri, G. Benenti, S. Montangero, E. Paladino, G. Falci
Summary: Ultrastrong coupling in superconducting circuit QED architectures allows for faster operations in the development of quantum technologies, although it also increases sensitivity to new kinds of intrinsic errors. By using optimal control methods, a resilient protocol against the main source of errors arising from the interplay of the dynamical Casimir effect with cavity losses is found.
NUOVO CIMENTO C-COLLOQUIA AND COMMUNICATIONS IN PHYSICS
(2022)
Article
Physics, Fluids & Plasmas
Vahid Shaghaghi, G. Massimo Palma, Giuliano Benenti
Summary: This study examines the statistical distribution of ergotropy and efficiency in a single-qubit battery and a single-qubit Otto engine fueled by random collisions. The interactions between the qubit and two reservoirs are described using a collision model of open system dynamics, revealing fluctuations in ergotropy, heat, and work that decrease with the size of the qudits in the hot reservoir. Although the mean macroscopic efficiency of the Otto engine remains the same, the distribution of efficiencies does not support finite moments, resulting in a discrepancy between the mean efficiency and the macroscopic efficiency.
Article
Quantum Science & Technology
Matteo Carrega, Loris Maria Cangemi, Giulio De Filippis, Vittorio Cataudella, Giuliano Benenti, Maura Sassetti
Summary: This study investigates the thermodynamic properties of quantum systems far from equilibrium, particularly when the system is strongly coupled to its environment or when memory effects cannot be neglected. The researchers find that by modulating the system-environment couplings, it is possible to perform thermodynamic tasks, such as extracting heat from a cold reservoir and realizing an ideal heat rectifier.
