scholarly journals Falling from Rest: Particle Creation in a Dropped Cavity

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1139
Author(s):  
Francesco Sorge
Keyword(s):  
Particle Creation ◽  
Gravitational Acceleration ◽  
Quantum Field ◽  
Two Dimensional ◽  
Quantum Vacuum ◽  
Equivalent Temperature ◽  
Time Duration ◽  
Static Gravitational Field ◽  
Typical Time ◽  
Scalar Quantum

We discuss the process of particle creation in the case of a scalar quantum field confined to a small cavity, initially at rest, which is suddenly dropped in a static gravitational field. We show that, due to the transition from a Schwarzschild to a Minkowski background, as perceived by a comoving observer, field particles are excited out of the quantum vacuum. The density of the created quanta depends on the proper gravitational acceleration as well as on a parameter α≃1/Δt, with Δt representing the typical time duration of the transition. For the specific acceleration profile considered, the energy spectrum of the created quanta roughly resembles a two-dimensional Planckian distribution, whose equivalent temperature mimics the Hawking-Unruh temperature, with the detector acceleration (or the black hole surface gravity) replaced by the parameter cα. We briefly comment on possible issues related to local Lorentz symmetry.

scholarly journals Thermal Casimir effect with general boundary conditions

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
J. M. Muñoz-Castañeda ◽  
L. Santamaría-Sanz ◽  
M. Donaire ◽  
M. Tello-Fraile
Keyword(s):  
Boundary Conditions ◽  
Vacuum Energy ◽  
Casimir Effect ◽  
Quantum Field ◽  
Quantum Vacuum ◽  
Parallel Plates ◽  
Casimir Forces ◽  
Thermal Correction ◽  
Frequency Independent ◽  
Scalar Quantum

Abstract In this paper we study the system of a scalar quantum field confined between two plane, isotropic, and homogeneous parallel plates at thermal equilibrium. We represent the plates by the most general lossless and frequency-independent boundary conditions that satisfy the conditions of isotropy and homogeneity and are compatible with the unitarity of the quantum field theory. Under these conditions we compute the thermal correction to the quantum vacuum energy as a function of the temperature and the parameters encoding the boundary condition. The latter enables us to obtain similar results for the pressure between plates and the quantum thermal correction to the entropy. We find out that our system is thermodynamically stable for any boundary conditions, and we identify a critical temperature below which certain boundary conditions yield attractive, repulsive, and null Casimir forces.

Radiation from moving mirrors and from black holes

1977 ◽  
Vol 356 (1685) ◽  
pp. 237-257 ◽  
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Black Holes ◽  
Particle Production ◽  
Quantum Particle ◽  
Flat Space ◽  
Stimulated Emission ◽  
Quantum Field ◽  
Two Dimensional ◽  
Scalar Quantum

We extend our previous work on scalar quantum particle production by moving mirrors in two-dimensional flat space-time to models with asymptotically null trajectories. This proves to have considerable heuristic value in understanding the mechanism of quantum particle emission from black holes. We demonstrate that Hawking’s derivation of that phenomenon using ray-tracing is mathematically identical to the geometrical optics associated with a certain class of mirror trajectory. Investigation of the simpler system clarifies the relation between particles and energy in quantum field theory. A mirror trajectory is presented by which a flux of particles is created, but no energy at all is radiated. We also show that the stimulated emission that occurs when a single particle is incident on the mirror simply corresponds to the classical reflexion of the associated wave, and that the total energy may decrease in this process.

scholarly journals Nonperturbative aspects of spontaneous symmetry breaking

2021 ◽  
Vol 36 (13) ◽  
pp. 2150074
Author(s):  
J. Gamboa ◽  
J. López-Sarrión
Keyword(s):  
Field Theory ◽  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Two Dimensions ◽  
Quantum Field ◽  
Two Dimensional ◽  
Yang Mills ◽  
Scalar Quantum ◽  
Infrared Limit ◽  
Theory Formula

Spontaneous symmetry breaking is studied in the ultralocal limit of a scalar quantum field theory, that is when [Formula: see text] (or infrared limit). In this infrared approximation the theory [Formula: see text] is formally two-dimensional and its Euclidean solutions are instantons. For BPST-like solutions with [Formula: see text], the map between [Formula: see text] in two dimensions and self-dual Yang–Mills theory is carefully discussed.

Application of Mathematical Modeling during Monitoring and Optimization of Non-Stationary Regime of Oil Well

2016 ◽  
Vol 11 (1) ◽  
pp. 53-59
Author(s):  
A.S. Topolnikov
Keyword(s):  
Mathematical Modeling ◽  
Model Problem ◽  
Cylindrical Tube ◽  
Field Measurements ◽  
Stationary Flow ◽  
Stationary Regime ◽  
Oil Well ◽  
Time Duration ◽  
Typical Time ◽  
Radial Model

The paper presents results of modeling of periodical regime of oil well for the purpose of monitoring and optimization of its operation. To describe non-stationary flow in the reservoir a planar-radial model of filtration is employed. The flow of multiphase flux in the well elements (casing, tubing, annulus) is described by 1D Navier-Stoks equations. The pump work is modelled by specification of its rate-head curve. To estimate the typical time duration of the processes in the well and in the reservoir a solution of a model problem for cylindrical tube is given. Through the examples a solution of a problem of optimization of periodical regime of oil wells is demonstrated. The comparison with field measurements is presented.

scholarly journals Bounding f(R) gravity by particle production rate

2016 ◽  
Vol 25 (04) ◽  
pp. 1630010 ◽  
Author(s):  
Salvatore Capozziello ◽  
Orlando Luongo ◽  
Mariacristina Paolella
Keyword(s):  
Field Theory ◽  
Particle Production ◽  
High Redshift ◽  
Dark Side ◽  
Quantum Field ◽  
Quantum Vacuum ◽  
Vacuum States ◽  
Text Model ◽  
Free Parameters ◽  
The Given

Several models of [Formula: see text] gravity have been proposed in order to address the dark side problem in cosmology. However, these models should be constrained also at ultraviolet scales in order to achieve some correct fundamental interpretation. Here, we analyze this possibility comparing quantum vacuum states in given [Formula: see text] cosmological backgrounds. Specifically, we compare the Bogolubov transformations associated to different vacuum states for some [Formula: see text] models. The procedure consists in fixing the [Formula: see text] free parameters by requiring that the Bogolubov coefficients can be correspondingly minimized to be in agreement with both high redshift observations and quantum field theory predictions. In such a way, the particle production is related to the value of the Hubble parameter and then to the given [Formula: see text] model. The approach is developed in both metric and Palatini formalism.

scholarly journals The dissipative approach to quantum field theory: conceptual foundations and ontological implications

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrea Oldofredi ◽  
Hans Christian Öttinger
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Nonequilibrium Thermodynamics ◽  
Particle Creation ◽  
Mathematical Structure ◽  
Alternative Formulation ◽  
Quantum Field ◽  
Conceptual Foundations ◽  
Particle Creation And Annihilation

AbstractMany attempts have been made to provide Quantum Field Theory with conceptually clear and mathematically rigorous foundations; remarkable examples are the Bohmian and the algebraic perspectives respectively. In this essay we introduce the dissipative approach to QFT, a new alternative formulation of the theory explaining the phenomena of particle creation and annihilation starting from nonequilibrium thermodynamics. It is shown that DQFT presents a rigorous mathematical structure, and a clear particle ontology, taking the best from the mentioned perspectives. Finally, after the discussion of its principal implications and consequences, we compare it with the main Bohmian QFTs implementing a particle ontology.

scholarly journals Quantum computation of scattering in scalar quantum field theories

2014 ◽  
Vol 14 (11&12) ◽  
pp. 1014-1080 ◽  
Author(s):  
Stephen P. Jordan ◽  
Keith S. M. Lee ◽  
John Preskill
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Strong Coupling ◽  
Interaction Strength ◽  
Quantum Algorithm ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Scalar Quantum ◽  
Relativistic Scattering ◽  
Fundamental Physical

Quantum field theory provides the framework for the most fundamental physical theories to be confirmed experimentally and has enabled predictions of unprecedented precision. However, calculations of physical observables often require great computational complexity and can generally be performed only when the interaction strength is weak. A full understanding of the foundations and rich consequences of quantum field theory remains an outstanding challenge. We develop a quantum algorithm to compute relativistic scattering amplitudes in massive $\phi^4$ theory in spacetime of four and fewer dimensions. The algorithm runs in a time that is polynomial in the number of particles, their energy, and the desired precision, and applies at both weak and strong coupling. Thus, it offers exponential speedup over existing classical methods at high precision or strong coupling.

scholarly journals NEGATIVE ENERGY DENSITIES IN QUANTUM FIELD THEORY

2010 ◽  
Vol 25 (11) ◽  
pp. 2355-2363 ◽  
Author(s):  
L. H. FORD
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Energy Density ◽  
Negative Energy ◽  
Mean Value ◽  
Quantum Field ◽  
Two Dimensional ◽  
Vacuum Fluctuations ◽  
Negative Energy Density ◽  
Dimensional Spacetime

Quantum field theory allows for the suppression of vacuum fluctuations, leading to sub-vacuum phenomena. One of these is the appearance of local negative energy density. Selected aspects of negative energy will be reviewed, including the quantum inequalities which limit its magnitude and duration. However, these inequalities allow the possibility that negative energy and related effects might be observable. Some recent proposals for experiments to search for sub-vacuum phenomena will be discussed. Fluctuations of the energy density around its mean value will also be considered, and some recent results on a probability distribution for the energy density in two dimensional spacetime are summarized.

Integrable Quantum Field Theories

2020 ◽  
pp. 575-621
Author(s):  
Giuseppe Mussardo
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Field Theories ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Two Dimensional ◽  
Conformal Theory ◽  
Integrable Quantum ◽  
Set Up ◽  
Integrable Quantum Field Theory

Chapter 16 covers the general properties of the integrable quantum field theories, including how an integrable quantum field theory is characterized by an infinite number of conserved charges. These theories are illustrated by means of significant examples, such as the Sine–Gordon model or the Toda field theories based on the simple roots of a Lie algebra. For the deformations of a conformal theory, it shown how to set up an efficient counting algorithm to prove the integrability of the corresponding model. The chapter focuses on two-dimensional models, and uses the term ‘two-dimensional’ to denote both a generic two-dimensional quantum field theory as well as its Euclidean version.

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