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The next few years will be exciting as prototype universal quantum processors emerge, enabling implementation of a wider variety of algorithms. Of particular interest are quantum heuristics, which require experimentation on quantum hardware…

Devising efficient algorithms that track the optimizers of continuously varying convex optimization problems is key in many applications. A possible strategy is to sample the time-varying problem at constant rate and solve the resulting…

Optimization and Control · Mathematics 2017-11-28 Andrea Simonetto

A quantum mechanical theory is proposed which abandons an external parameter ``time'' in favor of a self-adjoint operator on a Hilbert space whose elements represent measurement events rather than system states. The standard quantum…

Quantum Physics · Physics 2009-09-29 Kim Bostroem

In quantum mechanics time usually appears as classical parameter which means that it is treated as being essentially different from spatial coordinates that are represented by operators. On the other hand, relativity theory demands to treat…

Quantum Physics · Physics 2021-06-30 Slobodan Prvanović , Dušan Arsenović

Usual quantum mechanics predicts probabilities for the outcomes of measurements carried out at definite moments of time. However, realistic measurements do not take place in an instant, but are extended over a period of time. The assumption…

Quantum Physics · Physics 2009-10-30 Richard J. Micanek , James B. Hartle

We study the positive-operator-valued measures on the projective real line covariant with respect to the projective group, assuming that the energy is a positive operator. This problem is similar to the more complicated problem of finding…

Quantum Physics · Physics 2007-05-23 N. Pinamonti , M. Toller

We present a second quantization description of frequency-based continuous variables quantum computation in the subspace of single photons. For this, we define frequency and time operators using the free field Hamiltonian and its Fourier…

Quantum Physics · Physics 2022-06-01 Nicolas Fabre , Camille Nous , Arne Keller , Pérola Milman

A modification of the covariant theory is proposed in which the self-energy of the system, corresponding to time-like degrees of freedom in the configuration space, preserves the classical law of change in quantum theory. As a result,…

General Relativity and Quantum Cosmology · Physics 2020-01-27 Natalia Gorobey , Alexander Lukyanenko

Continuous clocks, i.e. the clocks that measure time in a continuous manner, are regarded as an essential component of sensing technology. Precision and recurrence time are two basic features of continuous clocks. In this paper, in the…

Quantum Physics · Physics 2022-09-02 Mehdi Ramezani , Morteza Nikaeen , Alireza Bahrampour

The decoherent histories approach to quantum theory is applied to a class of reparametrization invariant models, which includes systems described by the Klein-Gordon equation, and by a minisuperspace Wheeler-DeWitt equation. A key step in…

General Relativity and Quantum Cosmology · Physics 2009-11-11 J. J. Halliwell , P. Wallden

It is expected that a quantum theory of gravity will radically alter our current notion of spacetime geometry. However, contrary to what was commonly assumed for many decades, quantum gravity effects could manifest in scales much larger…

General Relativity and Quantum Cosmology · Physics 2026-05-14 Eduardo A. B. Oliveira , Andre G. S. Landulfo

The correspondence between classical and quantum invariants is established. The Ermakov Lewis quantum invariant of the time dependent harmonic oscillator is translated from the coordinate and momentum operators into amplitude and phase…

Quantum Physics · Physics 2013-03-13 M. Fernandez Guasti , H. Moya-Cessa

We claim that looking at probability distributions of \emph{finite time} largest Lyapunov exponents, and more precisely studying their large deviation properties, yields an extremely powerful technique to get quantitative estimates of…

Chaotic Dynamics · Physics 2009-10-20 Roberto Artuso , Cesar Manchein

The review of star-product formalism providing the possibility to describe quantum states and quantum observables by means of the functions called symbols of operators which are obtained by means of bijective maps of the operators acting in…

Quantum Physics · Physics 2019-03-20 S. N. Belolipetskiy , V. N. Chernega , O. V. Man'ko , V. I. Man'ko

We model ideal arrival-time measurements for free quantum particles and for particles subject to an external interaction by means of a narrow and weak absorbing potential. This approach is related to the operational approach of measuring…

Quantum Physics · Physics 2016-09-08 G. C. Hegerfeldt , D. Seidel , J. G. Muga , B. Navarro

We extend the concept of confined quantum time of arrival operators, first developed for the free particle [E.A. Galapon, R. Caballar, R. Bahague {\it Phys. Rev. Let.} {\bf 93} 180406 (2004)], to arbitrary potentials.

Quantum Physics · Physics 2007-05-23 Eric A. Galapon

Symplectic and optical joint probability representations of quantum mechanics are considered, in which the functions describing the states are the probability distributions with all random arguments (except the argument of time ). The…

Quantum Physics · Physics 2017-02-01 Ya. A. Korennoy , V. I. Man'ko

The failure of conventional quantum theory to recognize time as an observable and to admit time operators is addressed. Instead of focusing on the existence of a time operator for a given Hamiltonian, we emphasize the role of the…

Quantum Physics · Physics 2013-05-24 Curt A. Moyer

Time ordering may be defined by first defining the limit of no time ordering (NTO) in terms of a time average of an external interaction, V(t). Previously, time correlation was defined in terms of a similar limit called the independent time…

The origin and nature of time in complex systems is explored using quantum (or 'Feynman') clocks and the signals produced by them. Networks of these clocks provide the basis for the evolution of complex systems. The general concept of…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Scott Hitchcock
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