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The Wheeler-DeWitt (WDW) equation is analyzed using two boundary proposals: the Hartle-Hawking no-boundary condition and tunneling condition. By compactifying the scale factor $a$ into $ x = a/(1+a) $, we reformulate the WDW equation to…

General Relativity and Quantum Cosmology · Physics 2025-03-28 Jie Jiang , Deog Ki Hong , Dong-han Yeom

We study the quantum tunnel effect through a potential barrier employing a semiclassical formulation of quantum mechanics based on expectation values of configuration variables and quantum dispersions as dynamical variables. The evolution…

Quantum Physics · Physics 2020-12-30 L. Aragon-Muñoz , G. Chacon-Acosta , H. Hernandez-Hernandez

The Wheeler-DeWitt equation is investigated and used to examine a state after a quantum tunneling with gravity. To make arguments definite we treat a discretized version of the Wheeler-DeWitt equation and adopt the WKB method. We expand an…

General Relativity and Quantum Cosmology · Physics 2011-09-09 Shinji Mukohyama

We develop semiclassical methods for studying bubble nucleation in models with parameters that vary slowly in time. Introducing a more general rotation of the time contour allows access to a larger set of final states, and typically a…

High Energy Physics - Theory · Physics 2023-11-17 Patrick Draper , Manthos Karydas , Hao Zhang

An alternative approach to the calculation of tunneling actions, that control the exponential suppression of the decay of metastable phases, is presented. The new method circumvents the use of bounces in Euclidean space by introducing an…

High Energy Physics - Theory · Physics 2019-07-10 J. R. Espinosa

We study the temporal aspects of quantum tunneling as manifested in time-of-arrival experiments in which the detected particle tunnels through a potential barrier. In particular, we present a general method for constructing temporal…

Quantum Physics · Physics 2015-06-12 Charis Anastopoulos , Ntina Savvidou

We evaluate the Lorentzian gravitational path integral in the presence of non-vanishing torsion with the application of the Picard-Lefschetz theory for minisuperspaces corresponding to a number of phenomenological bouncing cosmological…

General Relativity and Quantum Cosmology · Physics 2024-04-15 Vikramaditya Mondal , Sumanta Chakraborty

For many years, the most active area of quantum cosmology has been the issue of choosing boundary conditions for the wave function of a universe. Recently, loop quantum cosmology, which is obtained from loop quantum gravity, has shed new…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Martin Bojowald , Kevin Vandersloot

Dissipative quantum tunnelling through an inverted parabolic barrier is considered in the presence of an electric field. A Schr\"odinger-Langevin or Kostin quantum classical transition wave equation is used and applied resulting in a scaled…

Quantum Physics · Physics 2018-10-03 S. V. Mousavi , S. Miret-Artés

We continue here the analysis of the previous paper of the Wheeler-DeWitt constraint operator for four-dimensional, Lorentzian, non-perturbative, canonical vacuum quantum gravity in the continuum. In this paper we derive the complete…

General Relativity and Quantum Cosmology · Physics 2009-10-28 T. Thiemann

The time dependent density matrix of a system with potential barrier is studied using path integrals. The characterization of the initial state, which is assumed to be restricted to one side of the barrier, and the time evolution of the…

Statistical Mechanics · Physics 2009-10-31 Joachim Ankerhold , Hermann Grabert

We review some recent attempts to extract information about the nature of quantum gravity, with and without matter, by quantum field theoretical methods. More specifically, we work within a covariant lattice approach where the individual…

High Energy Physics - Theory · Physics 2007-05-23 J. Ambjorn , J. Jurkiewicz , R. Loll

We provide a semiclassical theory of tunneling decay in a magnetic field and a three-dimensional potential of a general form. Because of broken time-reversal symmetry, the standard WKB technique has to be modified. The decay rate is found…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 T. Sharpee , M. I. Dykman , P. M. Platzman

Tunneling half lives are obtained in a minimalistic deformation picture of nuclear decays. As widely documented in other deformation models, one finds that the effective mass of the nucleus changes with the deformation parameter. However,…

Nuclear Theory · Physics 2024-08-28 Samyak Jain , A. Bhagwat

Process of dynamical tunneling in two-dimensional coupled potentials is considered within Bohmian approach to quantum mechanics. Quantum trajectories tend to go along the paths where potential energy increases and then decreases. It leads…

Chemical Physics · Physics 2007-05-23 Dmytro Babyuk

An improved Hamiltonian constraint operator is introduced in loop quantum cosmology. Quantum dynamics of the spatially flat, isotropic model with a massless scalar field is then studied in detail using analytical and numerical methods. The…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Abhay Ashtekar , Tomasz Pawlowski , Parampreet Singh

The tunneling probability for a system modelling macroscopic quantum tunneling is computed. We consider an open quantum system with one degree of freedom consisting of a particle trapped in a cubic potential interacting with an environment…

Quantum Physics · Physics 2007-05-23 Esteban Calzetta , Enric Verdaguer

Covariant models of loop quantum gravity generically imply dynamical signature change at high density. This article presents detailed derivations that show the fruitful interplay of this new kind of signature change with wave-function…

General Relativity and Quantum Cosmology · Physics 2021-05-27 Martin Bojowald , Suddhasattwa Brahma

In this paper, we analyze the dynamics of an isotropic closed Universe in the presence of a cosmological constant term and we compare its behavior in the standard Wheeler-DeWitt equation approach with the one when a Lagrangian fluid is…

General Relativity and Quantum Cosmology · Physics 2020-12-02 Andrea Campolongo , Giovanni Montani

We show that discrete-time quantum walks on the line, $\mathbb{Z}$, behave as "the quantum tunneling". In particular, quantum walkers can tunnel through a double-well with the transmission probability $1$ under a mild condition. This is a…

Quantum Physics · Physics 2017-12-06 Kaname Matsue , Leo Matsuoka , Osamu Ogurisu , Etsuo Segawa