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Neutrino oscillations appear to be a simple quantum mechanical phenomenon. However, a closer look at them reveals a number of subtle points and apparent paradoxes. Some of the basic issues of the theory of neutrino oscillations are still…

High Energy Physics - Phenomenology · Physics 2019-01-17 Evgeny Akhmedov

We investigate symmetric oscillators, and in particular their quantization, by employing semiclassical and quantum phase functions introduced in the context of Liouville-Green transformations of the Schr\"{o}dinger equation. For anharmonic…

Quantum Physics · Physics 2011-11-10 A. Matzkin , M. Lombardi

Conventional weak-coupling perturbation theory suffers from problems that arise from resonant coupling of successive orders in the perturbation series. Multiple-scale perturbation theory avoids such problems by implicitly performing an…

High Energy Physics - Theory · Physics 2009-10-30 Carl M. Bender , Luis M. A. Bettencourt

We present a practical course targeting graduate students with prior knowledge of the basics of quantum computing. The practical aims to deepen students' understanding of fundamental concepts in quantum computing by implementing quantum…

Physics Education · Physics 2025-11-24 Florian Krötz , Xiao-Ting Michelle To , Korbinian Staudacher , Dieter Kranzlmüller

The classical dynamical system possessing a quantum spectrum of energy and "quantum" behavior is suggested and investigated. The proposed model can be considered as a dynamical variant of the old quantum theory for harmonic oscillator in…

Quantum Physics · Physics 2011-05-27 Sergey A. Rashkovskiy

We revisit the quantized version of the harmonic oscillator obtained through a q-dependent family of coherent states. For each q, 0< q < 1, these normalized states form an overcomplete set that resolves the unity with respect to an explicit…

Mathematical Physics · Physics 2015-06-05 J. P. Gazeau , M. A. del Olmo

A one-dimensional quantum oscillator is monitored by taking repeated position measurements. As a first con- tribution, it is shown that, under a quantum nondemolition measurement scheme applied to a system initially at the ground state, (i)…

Quantum Physics · Physics 2015-11-13 Vincenzo Matta , Vincenzo Pierro

This paper provides necessary and sufficient conditions for constructing a universal quantum computer over continuous variables. As an example, it is shown how a universal quantum computer for the amplitudes of the electromagnetic field…

Quantum Physics · Physics 2009-10-31 Seth Lloyd , Samuel L. Braunstein

In this work we address the problem of the quantization of a simple harmonic oscillator that is perturbed by a time dependent force. The approach consists of removing the perturbation by a canonical change of coordinates. Since the…

Quantum Physics · Physics 2022-04-21 Henryk Gzyl

We address the problem of determining whether or not a harmonic oscillator has been perturbed by an external force. Quantum detection and estimation theory has been used in devising optimum measurement schemes. Detection probability has…

Quantum Physics · Physics 2015-06-26 Matteo G. A. Paris

The purpose of quantum technologies is to explore how quantum effects can improve on existing solutions for the treatment of information. Quantum photonics sensing holds great promises for reaching a more efficient trade-off between…

Quantum Physics · Physics 2025-07-31 Marco Barbieri

We present a generalized equations-of-motion method that efficiently calculates energy spectra and matrix elements for algebraic models. The method is applied to a 5-dimensional quartic oscillator that exhibits a quantum phase transition…

Nuclear Theory · Physics 2008-11-26 S. Y. Ho , G. Rosensteel , D. J. Rowe

We show that the unitary evolution of a harmonic oscillator coupled to a two-level system can be undone by a suitable manipulation of the two-level system -- more specifically: by a quasi-instantaneous phase change. This enables us to…

Quantum Physics · Physics 2010-03-26 Giovanna Morigi , Enrique Solano , Berthold-Georg Englert , Herbert Walther

Inspired by the advancements in large language models based on transformers, we introduce the transformer quantum state (TQS): a versatile machine learning model for quantum many-body problems. In sharp contrast to Hamiltonian/task specific…

Quantum Physics · Physics 2023-03-08 Yuan-Hang Zhang , Massimiliano Di Ventra

Quantum computing is usually associated with discrete quantum states and physical quantities possessing discrete eigenvalue spectrum. However, quantum computing in general is any computation accomplished by the exploitation of quantum…

Quantum Physics · Physics 2021-07-06 Samantha Buck , Robin Coleman , Hayk Sargsyan

A nonlinear model of the quantum harmonic oscillator on two-dimensional spaces of constant curvature is exactly solved. This model depends of a parameter $\la$ that is related with the curvature of the space. Firstly the relation with other…

Mathematical Physics · Physics 2010-11-11 José F. Cariñena , Manuel F. Rañada , Mariano Santander

A quantum measuring instrument is constructed that utilises symmetry breaking to enhance a microscopic signal. The entire quantum system consists of a system-apparatus-environment triad that is composed of a small set of spin-1/2 particles.…

Quantum Physics · Physics 2018-08-07 H. C. Donker , H. De Raedt , M. I. Katsnelson

We study a quantum oscillator interacting and back-reacting on a classical oscillator. This can be done consistently provided the quantum system decoheres, while the backreaction has a stochastic component which causes the classical system…

Quantum Physics · Physics 2025-04-24 Muhammad Sajjad , Andrea Russo , Maite Arcos , Andrzej Grudka , Jonathan Oppenheim

Simulating large-scale coupled-oscillator systems presents substantial computational challenges for classical algorithms, particularly when pursuing first-principles analyses in the thermodynamic limit. Motivated by the quantum algorithm…

Near term quantum hardware promises unprecedented computational advantage. Crucial in its development is the characterization and minimization of computational errors. We propose the use of the quantum fluctuation theorem to benchmark the…

Quantum Physics · Physics 2019-03-13 Bartłomiej Gardas , Sebastian Deffner