Article
Physics, Multidisciplinary
Lea Bresque, Patrice A. Camati, Spencer Rogers, Kater Murch, Andrew N. Jordan, Alexia Auffeves
Summary: The study introduces a two-qubit engine powered by entanglement and local measurements, and extends the energy conversion process to an N-qubit chain. It finally identifies the fueling mechanism and energy cost associated with erasing the correlations between the qubits.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Manik Banik, Tamal Guha, Mir Alimuddin, Guruprasad Kar, Saronath Halder, Some Sankar Bhattacharya
Summary: The research focuses on the discrimination of composite quantum states, revealing that an ensemble containing N pairwise orthogonal pure states can be perfectly distinguished under certain conditions. Examples of orthonormal bases in two-qubit Hilbert space requiring three copies for adaptive discrimination were provided, and the varying number of copies needed for discrimination under different schemes were analyzed.
PHYSICAL REVIEW LETTERS
(2021)
Article
Engineering, Multidisciplinary
M. R. Pourkarimi, S. Haddadi, M. Nashaat, K. V. Kulikov, Yu. M. Shukrinov
Summary: This paper investigates the thermal evolution of a two-qubit superconducting system by considering the local quantum uncertainty (LQU) as a measure of quantum correlations. It is shown that the thermal LQU can be increased by manipulating the Hamiltonian parameters, but undergoes sudden transitions at specific temperatures. Furthermore, the impact of decohering channels on thermal LQU is analyzed.
ALEXANDRIA ENGINEERING JOURNAL
(2023)
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
Optics
Richard A. Brewster, Gerald Baumgartner, Yanne K. Chembo
Summary: A general technique is introduced to experimentally characterize the effect of qubit-preserving impairments on the Clauser-Horne-Shimony-Holt parameter. This technique is independent of the qubit encoding and is theoretically demonstrated for specific impairments in polarization-encoded quantum-optical qubits. The analysis also includes the incorporation of spectrotemporal impairments into this technique.
Article
Optics
Jaromir Fiurasek, Robert Starek, Michal Micuda
Summary: This study focuses on designing optimal interferometric schemes for the implementation of two-qubit linear-optical quantum filters diagonal in the computational basis. The filtering is achieved through the interference of two photons encoding the qubits and conditioning on the presence of a single photon in each output port. The optimal filters are those that maximize the overall success probability, which may require additional overhead in terms of reduced success probability.
Article
Quantum Science & Technology
Amara Katabarwa, Sukin Sim, Dax Enshan Koh, Pierre-Luc Dallaire-Demers
Summary: This study characterizes two-qubit parameterized quantum circuits using principal bundles and discovers the relationship between Ricci scalar and entanglement. By calculating the Ricci scalar, we find that the Quantum Natural Gradient outperforms standard gradient descent by identifying high negative curvature regions early in the optimization process, which is crucial for accelerating the optimization.
Article
Multidisciplinary Sciences
Shilan Abo, Jan Soubusta, Katerina Jirakova, Karol Bartkiewicz, Antonin Cernoch, Karel Lemr, Adam Miranowicz
Summary: We experimentally demonstrate a hierarchy of quantum entanglement, steering, and Bell nonlocality by measuring only six elements of a correlation matrix depending on linear combinations of two-qubit Stokes parameters. Our experimental setup also reveals the hierarchy of quantum correlations of generalized Werner states, which are any two-qubit pure states affected by white noise.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Multidisciplinary
Ignacio R. Sola, Vladimir S. Malinovsky, Jaewook Ahn, Seokmin Shin, Bo Y. Chang
Summary: By controlling the temporal and spatial features of light, we propose a novel protocol for preparing entangling gates on trapped atoms. The protocol is robust to variations in pulse areas and atom positions, and it uses structured light. We analyze the gate fidelity map and propose generalizations for multi-pulse sequences.
Article
Physics, Multidisciplinary
Kosuke Mitarai, Keisuke Fujii
Summary: The study demonstrates a method to simulate certain types of non-local operations by sampling a set of local operations, which can be used to evaluate the expectation value of observables in a quantum circuit. It also proposes a strategy to decompose a two-qubit gate into a sequence of single-qubit operations, enabling more efficient operations in quantum computing.
NEW JOURNAL OF PHYSICS
(2021)
Article
Quantum Science & Technology
Otto C. W. Kong, Hock King Ting
Summary: A generic scheme for parameterizing mixed-state systems is introduced, with a slightly modified version specifically designed for bipartite systems. The scheme is applied to analyze various features of two-qubit entanglement, emphasizing the interplay between pure states and mixed states.
QUANTUM INFORMATION PROCESSING
(2022)
Article
Quantum Science & Technology
Guo-Zhu Pan, Ming Yang, Hao Yuan, Gang Zhang, Jun-Long Zhao
Summary: This study introduces nonlinear steering criteria for arbitrary and symmetric quantum states, which can certify more steerable states and verify entanglement.
QUANTUM INFORMATION PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
A. -b. a. Mohamed, Abdel-Haleem Abdel-Aty, Eman G. El-Hadidy, Hala A. A. El-Saka
Summary: This theoretical study demonstrates how to control quantum entanglement of a dissipative anisotropic two-qubit Heisenberg XYZ model by manipulating the initial state setting, interaction, and decoherence. It shows new dynamical features and sudden changes in entanglement. Simultaneous changes in these behaviors for different values of system parameters were also considered.
RESULTS IN PHYSICS
(2021)
Article
Physics, Multidisciplinary
R. A. Abdelghany, A. -B. A. Mohamed, M. Tammam, A. -S. F. Obada
Summary: The nonclassical correlations in the two-qubit Ising model under different magnetic field directions were investigated, revealing relationships between LQFI and LQU. The dependence of nonclassical correlations on the magnetic field direction, magnitude, and spin interaction coupling was explored, as well as the sudden changes in LQFI and LQU related to entanglement based on temperature and magnetic field magnitude.
EUROPEAN PHYSICAL JOURNAL PLUS
(2021)
Editorial Material
Physics, Multidisciplinary
Federico Levi
Summary: This article discusses what makes a good qubit.
Article
Physics, Multidisciplinary
Martin Plavala, Mario Ziman
Article
Physics, Multidisciplinary
I. A. Luchnikov, S. V. Vintskevich, D. A. Grigoriev, S. N. Filippov
PHYSICAL REVIEW LETTERS
(2020)
Article
Physics, Multidisciplinary
Sergey N. Filippov, Stan Gudder, Teiko Heinosaari, Leevi Leppajarvi
FOUNDATIONS OF PHYSICS
(2020)
Article
Physics, Multidisciplinary
Roberto Grimaudo, Antonino Messina, Alessandro Sergi, Nikolay V. Vitanov, Sergey N. Filippov
Article
Physics, Multidisciplinary
Sergey N. Filippov
Summary: Losses in quantum communication lines can be state-dependent, with polarization-dependent losses being a prominent example. This study introduces the concept of a generalized erasure channel and analyzes biased trace decreasing quantum operations. The results show superadditivity of coherent information in the case of polarization dependent losses, with a significant difference between two-letter and single-letter quantum capacity.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2021)
Article
Physics, Multidisciplinary
Ilia A. Luchnikov, Alexander Ryzhov, Sergey N. Filippov, Henni Ouerdane
Summary: The study introduces a library called QGOpt for solving constrained optimization problems in quantum technology. QGOpt relies on Riemannian structures and TensorFlow for optimization, allowing the use of gradient-based methods while preserving quantum mechanical constraints.
Article
Physics, Multidisciplinary
Ilia A. Luchnikov, Mikhail E. Krechetov, Sergey N. Filippov
Summary: The use of Riemannian optimization in quantum physics and quantum information science has shown effectiveness in solving optimization problems with constraints, such as low-energy spectrum and eigenstates of multipartite Hamiltonians, variational search of tensor networks, preparation of arbitrary quantum states, decomposition of quantum gates, and tomography of quantum states. The universality of this approach allows for its application to complex quantum architectures beyond the problems listed, including optimal control of noisy quantum systems.
NEW JOURNAL OF PHYSICS
(2021)
Article
Physics, Multidisciplinary
Sergey Filippov
Summary: Researchers have developed a tensor network formalism to address the challenges in standard collision models, namely, describing quantum correlations among ancillas induced by successive system-ancilla interactions, and dealing with initially correlated ancillas. They found that matrix product state (matrix product density operator) is effective in capturing induced correlations in the standard collision model if the colliding particles are in pure (mixed) states. Additionally, they constructed a general tensor diagram for system dynamics and derived a memory-kernel master equation to handle initially correlated ancillas, considering multipoint correlations beyond two-point correlations.
Article
Physics, Multidisciplinary
Hazhir Dolatkhah, Saeed Haddadi, Soroush Haseli, Mohammad Reza Pourkarimi, Mario Ziman
Summary: In this work, tripartite quantum-memory-assisted entropic uncertainty relations for multiple measurements are obtained, with lower bounds depending on the complementarity of observables, conditional von-Neumann entropies, Holevo quantities, and mutual information. The saturation of these inequalities is also analyzed.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Physics, Multidisciplinary
Sergey Filippov, Alena Termanova
Summary: In the realm of continuous-variable states and local Gaussian channels, the assumption that the optimal initial state with the most robust entanglement is Gaussian is proven to be false. Specific non-Gaussian two-mode states are shown to remain entangled under the effect of deterministic local attenuation or amplification. These results challenge the Gaussian world paradigm in quantum information science.
Article
Optics
Jaroslav Pavlicko, Mario Ziman
Summary: In this study, we investigate the robustness of a probabilistic storage and retrieval device optimized for phase gates to noise. We find that the device exhibits higher resistance to dephasing noise compared to depolarization noise. Interestingly, we observe that the retrieval process reduces the degree of noise for depolarization. Additionally, we examine different possible realizations of the device and observe differences in their performance in the presence of noise.
Article
Physics, Multidisciplinary
I. A. Luchnikov, E. O. Kiktenko, M. A. Gavreev, H. Ouerdane, S. N. Filippov, A. K. Fedorov
Summary: The article introduces a data-driven approach to analyzing the non-Markovian dynamics of open quantum systems, which can capture key characteristics of the system and reconstruct predictive models while denoising measured data.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Optics
Sergey N. Filippov
Summary: This study considers polarization-dependent losses and proposes physically motivated multipartite entangled states that outperform factorized states, which is significant for improving quantum communication rates.
Article
Optics
Sergey N. Filippov, Ilia A. Luchnikov
Summary: This paper presents an exact solution to the interaction problem between a quantum system and individual particles or modes using the tensor network formalism. The solution addresses the challenges posed by classical and quantum environment correlations, advancing the application of tensor-network methods in quantum optics and quantum transport.
Article
Optics
Michal Sedlak, Mario Ziman
