Article
Physics, Multidisciplinary
Anne-Catherine De la Hamette, Stefan L. Ludescher, Markus P. Mueller
Summary: In the quantization of gauge theories and quantum gravity, treating reference frames as internal quantum subsystems rather than idealized external classical relata is crucial. By studying the quantitative correspondence between the entanglement in the invariant state on the reference frame and the asymmetry in the corresponding conditional state, we shed light on the mechanism of establishing asymmetry in a fully symmetric quantum world.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Rhea Alexander, Si Gvirtz-Chen, David Jennings
Summary: Symmetry principles are fundamental in physics, and their impact on quantum channels presents several open questions. The theory of asymmetry provides a means to quantify the encoding of symmetry group coordinates in quantum systems. A recent study has identified a complete set of entropic conditions for asymmetry, but their practical application is challenging.
NEW JOURNAL OF PHYSICS
(2022)
Article
Astronomy & Astrophysics
Leonardo Chataignier
Summary: The paper discusses the construction of relational observables in time-reparametrization invariant quantum mechanics and argues that their physical interpretation can be understood in terms of conditional probabilities, defined from solutions of the quantum constraint equation. It shows how conditional expectation values of worldline tensor fields are related to quantum averages of relational observables. The dynamics of these observables is related to a notion of quantum reference frames.
Article
Chemistry, Physical
J. Vester, V. Despre, A. I. Kuleff
Summary: Due to electron correlation, the removal of an electron from a molecule can lead to coherent superposition of cationic states, resulting in pure electronic dynamics in which the ionization-induced hole migrates throughout the system in a short time scale. The coupling to nuclear motion introduces decoherence that traps the charge, and it is important to understand the duration of electronic coherence and the dominant nuclear degrees of freedom responsible for decoherence. Quantum calculations of propynamide reveal that electronic coherences last only 2-3 fs before being destroyed by nuclear motion. Symmetric in-plane modes are primarily responsible for fast electronic decoherence, while other modes have little or no effect on charge migration. This information can guide the development of reduced dimensionality models or the search for molecules with long coherence times.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Otto C. W. Kong
Summary: The study focuses on how the 'value' of an observable changes with a fixed state in quantum reference frame transformations, considering quantum fluctuations and entanglement. The recently introduced notion of noncommutative values successfully provides a definite description of such transformations, alongside an analysis of cases in systems with discrete or finite spectra. Discussions on the evolving picture of the symmetry system of all quantum reference frame transformations are also presented.
RESULTS IN PHYSICS
(2021)
Article
Quantum Science & Technology
Angel Ballesteros, Flaminia Giacomini, Giulia Gubitosi
Summary: The study shows that the transformation laws between quantum reference frames need to be modified to consider the quantum and dynamical features, revealing a group structure different from the usual Galilei algebra of quantum mechanics. The elements of this new algebra are found to be the building blocks of the previously identified quantum reference frames transformations. Additionally, it is demonstrated how transformations between classical reference frames described by the standard Galilei group symmetries can be obtained by taking the zero limit of the parameter governing the noncommutativity introduced by the quantum nature of inertial transformations.
Article
Astronomy & Astrophysics
Ahmad Jafar Arifi, Ho-Meoyng Choi, Chueng-Ryong Ji, Yongseok Oh
Summary: The issue of obtaining the same physical observables with different current components, particularly from the minus current, is a challenging problem in the light-front quark model (LFQM). In this study, we demonstrate the uniqueness of pseudoscalar and vector meson decay constants in the LFQM by considering all available components, including the minus component, consistent with the Bakamjian-Thomas construction. Regardless of the current components, polarization vectors, and reference frames, the meson decay constants can be uniquely determined in the noninteracting constituent quark and antiquark basis, while incorporating the interactions of the constituents in the meson mass operator in the LFQM.
Article
Chemistry, Multidisciplinary
Esin Kasapoglu, Melike Behiye Yucel, Carlos A. Duque
Summary: In this study, we investigated the optical properties of electrons in symmetrical and asymmetrical double quantum wells under an applied magnetic field. The calculations were carried out using the effective mass and parabolic band approximations. By diagonalization, we obtained the eigenvalues and eigenfunctions of the confined electron. The linear and third-order non-linear optical absorption and refractive index coefficients were calculated using a two-level density matrix expansion. The proposed potential model is valuable for simulating and controlling the optical and electronic properties of double quantum heterostructures subjected to externally applied magnetic fields.
Article
Nanoscience & Nanotechnology
Rong Shi, Jiang Zheng, Tianjiao Li, Haoge Shou, Dongdi Yin, Jinsong Rao
Summary: In this study, the influences of texture on the fatigue behavior and cracking modes of magnesium alloy were investigated. The results show that the deformation modes and cracking modes are closely related to the texture. The cyclic deformation-mode transitions and the factors governing microcrack nucleation were analyzed.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Automation & Control Systems
Jian Yang, Jingyang Zhou, Hanbin Zhou, Feng Yi, Dongran Song, Mi Dong
Summary: This article investigates high-precision harmonic current extraction for permanent magnet synchronous motor using multiple reference frames (MRF) and taking into account the disturbance of speed harmonics. The article analyzes the extraction error caused by speed harmonics in MRF and proposes a novel preprocessing method that effectively suppresses the extraction error. Furthermore, a variable forgetting factor recursive least squares algorithm is proposed for fast and accurate preprocessing.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Computer Science, Software Engineering
Robin Skanberg, Martin Falk, Mathieu Linares, Anders Ynnerman, Ingrid Hotz
Summary: Spatial distribution functions (SDF) are fundamental instruments in molecular analysis for understanding the spatial occurrences and relations of atomic structures over time. This study introduces the concept of an internal frame of reference (IFR) and proposes an algorithm to track the IFR over time and space. The usefulness of this technique is demonstrated through its application to temporal molecular trajectories and ensemble datasets.
IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS
(2022)
Article
Physics, Particles & Fields
Sylvain Carrozza, Philipp A. Hohn
Summary: We introduce a general framework for realizing edge modes as dynamical reference frames in gauge field theory, providing an explicit interpretation. By isolating the subsector of the global theory compatible with gauge-invariant boundary conditions for dynamics in a bounded region, we establish consistent variational principles and boundary actions. The resulting dynamics for the subregion manifest as edge modes, which are influenced by boundary symmetries.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
N. Moreau, B. Brun, S. Somanchi, K. Watanabe, T. Taniguchi, C. Stampfer, B. Hackens
Summary: Observations of electron-hole asymmetry in transport through graphene devices at high magnetic field challenge prevalent models of the graphene quantum Hall effect. The presence of upstream modes and local doping in the vicinity of electrical contacts leads to a different topological breakdown for electrons and holes, explaining the observed asymmetry.
Article
Construction & Building Technology
Chisanga Kaluba, Alphose Zingoni
Summary: This paper presents a computationally efficient formulation based on group theory for the buckling analysis of symmetric plane frames. By utilizing the full symmetry of the configuration, the approach decomposes the n-dimensional problem into smaller, independent problems, resulting in higher reductions of computational effort. Additionally, insights on the character of buckling modes can be obtained before detailed computations are carried out.
JOURNAL OF STRUCTURAL ENGINEERING
(2021)
Article
Physics, Multidisciplinary
Johannes Piotrowski, Dominik Windey, Jayadev Vijayan, Carlos Gonzalez-Ballestero, Andres de los Rios Sommer, Nadine Meyer, Romain Quidant, Oriol Romero-Isart, Rene Reimann, Lukas Novotny
Summary: Researchers have successfully cooled a levitated nanoparticle in an optical cavity to its motional ground state in two degrees of freedom simultaneously. Control of the cavity properties also allowed for the observation of the transition from 1D to 2D ground-state cooling. This achievement is important for investigating macroscopic quantum states and building high fidelity sensors.
