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The usual way to reveal properties of an unknown quantum state, given many copies of a system in that state, is to perform measurements of different observables and to analyze the measurement results statistically. Here we show that the…

Quantum Physics · Physics 2014-11-25 Seth Lloyd , Masoud Mohseni , Patrick Rebentrost

p-Adic generalization of the Feynman path integrals in quantum mechanics is considered. The probability amplitude for a particle in a constant field is calculated. Path integrals over p-adic space have the same form as those over R.

Mathematical Physics · Physics 2007-05-23 Goran S. Djordjevic , Branko Dragovich

We discuss a progress in calculations of Feynman integrals based on the Gegenbauer Polynomial Technique and the Differential Equation Method. We demonstrate the results for a class of two-point two-loop diagrams and the evaluation of most…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. V. Kotikov

According to Wick's theorem, the second order self-energy corrections of hadrons in the hot and dense nuclear matter are calculated. Furthermore, the Feynman rules are summarized, and an effective formulation on quantum hadrodynamics at…

Nuclear Theory · Physics 2007-05-23 Bao-Xi Sun , Xiao-Fu Lu , Lei Li , Ping-Zhi Ning , Peng-Nian Shen , En-Guang Zhao

It is a common belief among field theorists that path integrals can be computed exactly only in a limited number of special cases, and that most of these cases are already known. However recent developments, which generalize the WKBJ method…

High Energy Physics - Theory · Physics 2009-10-22 Hans Dykstra , Joe Lykken , Eric Raiten

By means of the Ito-Nisio theorem, we introduce and discuss a general approach to series representations of path integrals. We then argue that the optimal basis for both ``primitive'' and partial averaged approaches is the Wiener…

Chemical Physics · Physics 2009-11-07 Cristian Predescu , J. D. Doll

We study a (relativistic) Wiener process on a complexified (pseudo-)Riemannian manifold. Using Nelson's stochastic quantization procedure, we derive three equivalent descriptions for this problem. If the process has a purely real quadratic…

Mathematical Physics · Physics 2022-05-17 Folkert Kuipers

The reweighted random series techniques provide finite-dimensional approximations to the quantum density matrix of a physical system that have fast asymptotic convergence. We study two special reweighted techniques that are based upon the…

Statistical Mechanics · Physics 2009-11-10 Cristian Predescu , Dubravko Sabo , J. D. Doll

We propose an algorithm based on variational quantum imaginary time evolution for solving the Feynman-Kac partial differential equation resulting from a multidimensional system of stochastic differential equations. We utilize the…

Path integral quantization of quantum gauge general relativity is discussed in this paper. First, we deduce the generating functional of green function with external fields. Based on this generating functional, the propagators of…

General Relativity and Quantum Cosmology · Physics 2008-12-17 Ning Wu

A generalized quantum kinetic equation (RKE) of the Kadanoff-Baym type is obtained on the basis of the Heisenberg equations of motion where the time evolution and space translation are separated from each other by means of the covariant…

High Energy Physics - Phenomenology · Physics 2009-10-31 S. A. Smolyansky , A. V. Prozorkevich , G. Maino , S. G. Mashnik

The Feynman-Vernon path integral formalism is used to derive the density matrix of a quantum oscillator that is linearly coupled to an environmental reservoir. Although low-temperature reservoirs thermalize the oscillator to the usual…

General Physics · Physics 2014-12-15 George E. Cragg

In this article, we present a novel approach to investigating entanglement in the context of quantum computing. Our methodology involves analyzing reduced density matrices at different stages of a quantum algorithm's execution and…

Quantum Physics · Physics 2024-03-14 Ruge Lin

We study the interplay of general relativity, the equivalence principle, and high-precision experiments involving atomic transitions and g factor measurements. In particular, we derive a generalized Dirac Hamiltonian, which describes both…

High Energy Physics - Phenomenology · Physics 2019-04-26 Ulrich D. Jentschura

Quantum phase estimation is the workhorse behind any quantum algorithm and a promising method for determining ground state energies of strongly correlated quantum systems. Low-cost quantum phase estimation techniques make use of circuits…

Quantum Physics · Physics 2019-03-27 T. E. O'Brien , B. Tarasinski , B. M. Terhal

We consider a one-dimensional space-inhomogeneous discrete time quantum walk. This model is the Hadamard walk with one defect at the origin which is different from the model introduced by Wojcik et al. [14]. We obtain a stationary measure…

Mathematical Physics · Physics 2015-07-31 Takako Endo , Norio Konno , Etsuo Segawa , Masato Takei

The variational quantum eigensolver (or VQE) uses the variational principle to compute the ground state energy of a Hamiltonian, a problem that is central to quantum chemistry and condensed matter physics. Conventional computing methods are…

We propose a new quantum computational way of obtaining a ground-state energy and expectation values of observables of interacting Hamiltonians. It is based on the combination of the adiabatic quantum evolution to project a ground state of…

Quantum Physics · Physics 2009-10-31 Sangchul Oh

We develop a new representation for the integrals associated with Feynman diagrams. This leads directly to a novel method for the numerical evaluation of these integrals, which avoids the use of Monte Carlo techniques. Our approach is based…

High Energy Physics - Phenomenology · Physics 2009-10-31 Richard Easther , Gerald Guralnik , Stephen Hahn

Feynman path integrals formalism for non-relativistic quantum mechanics is revisited. A comparison is made with the cases of light progagation (Huygens principle) and Brownian motion. The difficulties for a physical model behind Feynman…

Quantum Physics · Physics 2025-10-09 Emilio Santos
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