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We adapt the axioms of the quantum mechanics to the quantum Minkowski space-time coordinates and their transformations under the quantum Lorentz group to show how we can formulate the noncommutative special relativity and its quantum…

Mathematical Physics · Physics 2007-05-23 M. Lagraa

We demonstrate in this paper that the probabilities for sequential measurements have features very different from those of single-time measurements. First, they cannot be modelled by a classical stochastic process. Second, they are…

Quantum Physics · Physics 2009-11-11 Charis Anastopoulos

In quantum mechanics, spatial correlations arising from measurements at separated particles are well studied. This is not the case, however, for the temporal correlations arising from a single quantum system subjected to a sequence of…

Quantum Physics · Physics 2018-11-13 Jannik Hoffmann , Cornelia Spee , Otfried Gühne , Costantino Budroni

We introduce a symbolic operator framework for simulating quantum photonic systems that works directly with the canonical commutation relations and the Weyl algebra. Unlike existing Fock-space or Gaussian simulators, our method treats…

Quantum Physics · Physics 2026-03-13 Simon Sekavcnik , Janis Noetzel

In this paper we consider eigenvalues asymptotics of the energy operator in the one of the most interesting models of quantum physics, describing an interaction between two-level system and harmonic oscillator. The energy operator of this…

Spectral Theory · Mathematics 2018-11-13 Eduard Yanovich

Quantum estimation of the operators of a system is investigated by analyzing its Liouville space of operators. In this way it is possible to easily derive some general characterization for the sets of observables (i.e. the possible quorums)…

Quantum Physics · Physics 2009-11-06 G. M. D'Ariano , L. Maccone , M. G. A. Paris

We show that coupling ultracold atoms in optical lattices to quantized modes of an optical cavity leads to quantum phases of matter, which at the same time posses properties of systems with both short- and long-range interactions. This…

Quantum Gases · Physics 2016-07-06 Santiago F. Caballero-Benitez , Gabriel Mazzucchi , Igor B. Mekhov

In this work we will advance farther along a line previously developed concerning our proposal of a time interval operator, on finite dimensional spaces. The time interval operator is Hermitian, and its eigenvalues are time values with a…

Quantum Physics · Physics 2007-05-23 M. Ruzzi , D. Galetti

Students in quantum mechanics class are taught that the wave function contains all knowable information about an isolated system. Later in the course, this view seems to be contradicted by the mysterious density matrix, which introduces a…

General Physics · Physics 2021-04-16 Mark G. Kuzyk

For a bi-partite quantum system defined in a finite dimensional Hilbert space we investigate in what sense entanglement change and interactions imply each other. For this purpose we introduce an entanglement operator, which is then shown to…

Quantum Physics · Physics 2009-11-07 J. Gemmer , G. Mahler

Time-translation symmetry strongly constrains physical dynamics, yet systematic characterization for continuous-variable systems lags behind its discrete-variable counterpart. We close this gap by providing a rigorous classification of…

We provide theory, algorithms, and simulations of non-equilibrium quantum systems using a one-dimensional (1D) completely-positive (CP), matrix-product (MP) density-operator ($\rho$) representation. By generalizing the matrix product…

Quantum Physics · Physics 2025-09-16 Amit Jamadagni , Eugene Dumitrescu

We construct relational observables in group field theory (GFT) in terms of covariant positive operator-valued measures (POVMs), using techniques developed in the context of quantum reference frames. We focus on matter quantum reference…

General Relativity and Quantum Cosmology · Physics 2025-09-03 Luca Marchetti , Edward Wilson-Ewing

We present in the article the formulation of a version of Lorentz covariant quantum mechanics based on a group theoretical construction from a Heisenberg-Weyl symmetry with position and momentum operators transforming as Minkowski…

General Physics · Physics 2020-02-18 Suzana Bedić , Otto C. W. Kong , Hock King Ting

Motivated by the parametrization invariance of cosmological Lagrangians and their equivalence to systems describing the motion of particles in curved backgrounds, we identify the phase space analogue of the notion of proper time. We define…

General Relativity and Quantum Cosmology · Physics 2025-04-15 N. Dimakis

We introduce the concept of quantum observables over time (QOOT), an operator that jointly describes two observables at two distinct time points, as a dual of the quantum state over time formalism. We provide a full characterization of the…

Quantum Physics · Physics 2024-12-17 Gabriele Bressanini , Farhan Hanif , Hyukjoon Kwon , M. S. Kim

We generalize the operational quasiprobability involving sequential measurements proposed by Ryu {\em et al.} [Phys. Rev. A {\bf 88}, 052123] to a continuous-variable system. The quasiprobabilities in quantum optics are incommensurate,…

Quantum Physics · Physics 2017-11-02 Jeongwoo Jae , Junghee Ryu , Jinhyoung Lee

The questions we raise in this letter are as follows: What is the most general representation of a quantum state at a single point in time? Can we adapt the current formalisms to situations where the order of quantum operations is…

Quantum Physics · Physics 2024-06-21 Onur Pusuluk , Zafer Gedik , Vlatko Vedral

It is first shown that the Dirac's equation in a relativistic frame could be modified to allow discrete time, in agreement to a recently published upper bound. Next, an exact self-adjoint $4\times 4$ relativistic time operator for…

Quantum Physics · Physics 2017-06-26 Sina Khorasani

We propose that measurements of time-of-arrival correlations in multi-partite systems can sharply distinguish between different approaches to the time-of-arrival problem. To show this, we construct a Positive-Operator-Valued measure for two…

Quantum Physics · Physics 2017-03-15 Charis Anastopoulos , Ntina Savvidou