Article
Astronomy & Astrophysics
Bart Horn
Summary: We investigate asymptotic symmetries that preserve the Bondi gauge conditions but do not preserve the asymptotic falloff conditions for the metric near the null boundary and their connection to soft graviton theorems for scattering amplitudes.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Astronomy & Astrophysics
D. Dalmazi
Summary: Modern massive gravity theories address the historical tension between the absence of mass discontinuity and the absence of ghosts by introducing a fine-tuned gravitational potential and a sophisticated screening mechanism. Linearized nonlocal theories with exponential terms offer a solution to these issues and can be further extended to non-linear completions.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Astronomy & Astrophysics
Wojciech Krynski
Summary: This study focuses on dispersionless Lax systems and proposes a systematic method for deriving new integrable systems from existing ones. Several examples, including the dispersionless Hirota equation, the generalized heavenly equation, and equations related to Veronese webs, are provided to demonstrate the effectiveness of the proposed method.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Astronomy & Astrophysics
Jose P. S. Lemos, Oleg B. Zaslavskii
Summary: In this study, we investigate a black hole surrounded by a hot self-gravitating thin shell in the canonical ensemble. Using the Euclidean path integral approach, we derive the quantum statistical mechanics partition function of this matter-black hole system and obtain the thermodynamics of the system. We find that the total entropy is solely determined by the gravitational radius of the system and is not affected by the black hole inside the shell. We also determine the free energy, thermodynamic energy, and the temperature stratification along the system. Additionally, we establish the first law of thermodynamics and analyze the thermodynamic stability of the system through the calculation of the heat capacity.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Astronomy & Astrophysics
Fawzi Aly, Dejan Stojkovic
Summary: In this study, we investigate the behavior of perturbation waves in the Teukolsky equation using horizon-penetrating coordinates. We find that the radial functions satisfy physical boundary conditions and the Hertz-Weyl scalar equations preserve their characteristics in these coordinates. Using the angular equation, we construct the metric perturbation for a perturber orbiting a black hole in Kerr spacetime in a horizon-penetrating setting and provide an explicit formula for the metric perturbation.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Astronomy & Astrophysics
Robert Monjo
Summary: This paper proposes a modified gravity model that can explain the excess rotation of galaxies and mass-discrepancy acceleration, and it adjusts well to experimental data.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Astronomy & Astrophysics
Ashkan Alibabaei, Philip K. Schwartz, Domenico Giulini
Summary: This study investigates the Dirac equation coupled to an external electromagnetic field in a four-dimensional curved spacetime with a given timelike worldline representing a classical clock. By using generalised Fermi normal coordinates and performing expansions, a weak-gravity post-Newtonian expression for the Pauli Hamiltonian of a spin-half particle in an external electromagnetic field is derived.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Astronomy & Astrophysics
Gabriel Menezes
Summary: Multi-messenger astronomy provides us with the possibility of discovering phenomenological signatures of quantum-gravity effects. Feasible explorations within the effective field theory (EFT) treatment of general relativity have been discussed. Current techniques borrowed from modern amplitude methods were used to calculate leading quantum corrections to the classical radiated momentum and spectral waveforms. The results highlight the potential applications of the EFT approach in gravitational-wave physics. Furthermore, possible phenomenological surveys from the perspective of a UV completion for quantum gravity employing quadratic gravity were examined, revealing a deviation from the standard general-relativity prediction.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Astronomy & Astrophysics
N. Wanwieng, N. Chattrapiban, A. Watcharangkool
Summary: We investigate the influence of gravitational waves on a freely falling hydrogen atom by analyzing the dynamics of the bound electron described by the Dirac equation in the curved spacetime of a gravitational wave. We derive the corresponding Dirac Hamiltonian in the local inertial frame of the atom and employ the Foldy-Wouthuysen transformation to obtain a non-relativistic description. The analysis of interaction terms and comparison with flat spacetime counterparts provide valuable insights into the effects of gravitational waves on the hydrogen atom.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Astronomy & Astrophysics
Sukanta Panda, Abbas Tinwala, Archit Vidyarthi
Summary: This study employs the local momentum space technique to derive the first-order expansion of Feynman propagators for scalar field and graviton in the presence of background curvature. The obtained propagators are validated by comparing them with previous literature and traced heat kernel coefficients. These propagators are then utilized to calculate the one-loop divergences in the Vilkovisky-Dewitt's effective action for a scalar field non-minimally coupled with gravity in an arbitrary spacetime metric. The comparison between the VD effective action and the standard effective action reveals an important result regarding the limit kappa = 0 and the presence of gravity.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Quantum Science & Technology
Seonghoon Choi, Ignacio Loaiza, Artur F. Izmaylov
Summary: Measuring the expectation value of the molecular electronic Hamiltonian can be challenging, but a new method has been introduced to lower the variances of the fragments, reducing the number of measurements required.
Article
Quantum Science & Technology
Yuhong Song, Edwin Hsing-Mean Sha, Qingfeng Zhuge, Wenlong Xiao, Qijun Dai, Longshan Xu
Summary: This paper introduces a new quantum circuit simulation technique called QuanPath, which eliminates communication and synchronization in each step, resulting in significant reduction in communication cost and simulation acceleration. Experimental results show that QuanPath performs well and has good scalability when simulating quantum algorithms.
QUANTUM INFORMATION PROCESSING
(2023)
Article
Quantum Science & Technology
Arthur Vesperini, Roberto Franzosi
Summary: This work presents a comprehensive exploration of the entanglement and connectivity properties of graph states, with the introduction of new measures and methods. The findings reveal interesting implications for measurement processes and emphasize simplicity in data analysis. The work contributes to a deeper understanding of graph states and provides valuable information for quantum information processing and quantum computing applications.
ADVANCED QUANTUM TECHNOLOGIES
(2023)
Article
Quantum Science & Technology
Domenico Ribezzo, Roberto Salazar, Jakub Czartowski, Flora Segur, Gianmarco Lemmi, Antoine Petitjean, Noel Farrugia, Davide Bacco, Andre Xuereb, Alessandro Zavatta
Summary: This study investigates Quantum Random Access Codes (QRACs) by experimentally testing encoding and decoding strategies, as well as the resilience in the presence of noise. The results are significant for theoretical studies on quantum resource allocation and the implementation of quantum infrastructures coexisting with regular telecommunication networks.
ADVANCED QUANTUM TECHNOLOGIES
(2023)
Article
Materials Science, Multidisciplinary
M. Ceccardi, A. Zeugner, L. C. Folkers, C. Hess, B. Buechner, D. Marre, A. Isaeva, F. Caglieris
Summary: The recently discovered (MnBi2Te4)(Bi2Te3)(n) possess both magnetic and topological insulator properties. In the low temperature antiferromagnetic state and vanishing magnetic field, the n = 1 system is a topological insulator protected by time reversal and translation symmetries. It has been experimentally proven that when the antiferromagnetic phase transitions to a fully spin polarized state through the application of an external magnetic field, Weyl cones are formed in the conduction band of this system, which is accessible through intrinsic electronic doping.
NPJ QUANTUM MATERIALS
(2023)
Article
Quantum Science & Technology
Li Li, Ri-Gui Zhou, Xiao-Xue Zhang
Summary: This paper proposes two three-party quantum key agreement protocols based on the logical four-particle cluster state, showing improved efficiency and demonstrated security against attacks.
QUANTUM INFORMATION PROCESSING
(2023)
Article
Quantum Science & Technology
Ward van der Schoot, Robert Wezeman, Pieter Thijs Eendebak, Niels M. P. Neumann, Frank Phillipson
Summary: With the rise of quantum computing, the development of various quantum devices raises the question of how to evaluate and compare their performance. This paper provides an overview of quantum metrics and categorizes them into component, system, and application levels. The metrics are evaluated on the Starmon-5 device of Quantum Inspire, offering a comprehensive benchmark for quantum devices.
QUANTUM INFORMATION PROCESSING
(2023)
Article
Quantum Science & Technology
Ling Zhang, Jia-Hao Zhang, Xiang-Jun Xin, Chao-Yang Li
Summary: Based on Bell states, a quantum designated verifier signature (QDVS) scheme without a third party is proposed. The scheme utilizes entangled systems to generate private keys and quantum gate operations to generate and verify the signature. Security analysis shows that the QDVS scheme has the property of designated verifier signature and can resist various attacks. Compared with similar schemes without a third party, our scheme has lower cost, higher efficiency, and enhanced security.
QUANTUM INFORMATION PROCESSING
(2023)
Article
Quantum Science & Technology
Xinying Zhu, Ran Xia, Liuyang Xu
Summary: We present a high-performance scheme of soft quantum control to deterministically generate entangled NOON states between two magnon modes. With the assistance of Floquet engineering, effective couplings among the photon mode and two magnon modes are constructed, and a superconducting qubit is used as a data bus to provide an N-photon Fock state.
QUANTUM INFORMATION PROCESSING
(2023)
Article
Quantum Science & Technology
Youngrong Lim, Changhun Oh
Summary: Quasiprobability representations are important for analyzing quantum systems, and we propose classical algorithms for approximating outcome probabilities of a linear optical circuit. By modulating the shapes of quasiprobability distributions, we can reduce the negativity bound of the circuit and provide efficient estimation of outcome probabilities. Additionally, our algorithms can be used to approximate various matrix functions.
NPJ QUANTUM INFORMATION
(2023)