author={L. Sriramkumar and Thanu Padmanabhan},
  journal={International Journal of Modern Physics D},
We compare the different approaches presently available in literature to probe the vacuum structure of quantum fields in classical electromagnetic and gravitational backgrounds. We compare the results from the Bogolubov transformations and the effective Lagrangian approach with the response of monopole detectors (of the Unruh–DeWitt type) in noninertial frames in flat spacetime and in inertial frames in different types of classical electromagnetic backgrounds. We also carry out such a… 

Tables from this paper

Localized projective measurement of a quantum field in non-inertial frames

We propose a projective operator formalism that is well-suited to study the correlations of quantum fields in non-inertial frames and curved spacetimes. We generalize a Glauber model of detection of

On the thermodynamics of moving bodies

We model the situation in which a photon detector moves with constant velocity in a Minkowski heat-bath by considering an Unruh-DeWitt detector, with variable energy gap ℏω, moving on a brane, at a

Particle creation, classicality and related issues in quantum field theory: II. Examples from field theory

We adopt the general formalism, which was developed in Paper I to analyze the evolution of a quantized time-dependent oscillator, to address several questions in the context of quantum field theory

Time-frequency approach to relativistic correlations in quantum field theory

Moving detectors in relativistic quantum field theories reveal the fundamental entangled structure of the vacuum which manifests, for instance, through its thermal character when probed by a

Accelerated detectors and worldsheet horizons in AdS/CFT

We use the AdS/CFT correspondence to discuss the response of an accelerated observer to the quantum vacuum fluctuations. In particular, we study heavy quarks probing a strongly coupled CFT by

Gravitational tunneling in Lorentz violating gravity

Black holes in Lorentz violating gravity, such as Einstein–Aether or Hoˇrava–Lifshitz Gravity, are drastically different from their general relativistic siblings. Although they allow for superluminal

On the thermodynamics of moving bodies

We consider an Unruh–DeWitt particle detector, coupled to a massless scalar field, undergoing ‘acceleration with drift’ in a (1 + 3)-dimensional Minkowski spacetime. We use this to model inertial

Evolution of quantum field, particle content, and classicality in the three stage universe

We study the evolution of a quantum scalar field in a toy universe which has three stages of evolution, viz., (i) an early (inflationary) de Sitter phase (ii) radiation-dominated phase and (iii)

The unified energy as vacuum quintessence in wave equations

  • Physics
  • 2017
The vacuum composition determination is a great challenge in field theories. The unified field expression is yet less. Here, we completed a previous gauge field theory we established from the wave

Generalized Schwinger effect and particle production in an expanding universe

We discuss several aspects of particle production in: (a) time dependent electric field and (b) expanding Friedmann background. In the first part of the paper, we provide an algebraic mapping between



Quantum Field Theory in Curved Spacetime

These lectures deal with selected aspects of quantum field theory in curved spacetime including the following topics: (1) Quantization of fields on a curved background, particle creation by

Quantum Fields in Curved Space

This book presents a comprehensive review of the subject of gravitational effects in quantum field theory. Although the treatment is general, special emphasis is given to the Hawking black hole

Quantum Field Theory in Curved Spacetime

We review the mathematically rigorous formulation of the quantum theory of a linear field propagating in a globally hyperbolic spacetime. This formulation is accomplished via the algebraic approach,

The Casimir Effect and Its Applications

The Casimir effect is analyzed. This effect consists of a polarization of the vacuum of quantized fields which arises as a result of a change in the spectrum of vacuum oscillations when the

Quantum Field Theory in Curved Spacetime and Black Hole Thermodynamics

In this book, Robert Wald provides a pedagogical introduction to the formulation of quantum field theory in curved spacetime. He begins with a treatment of the ordinary one-dimensional quantum


We study the response of a detector that is coupled nonlinearly to a quantized complex scalar field in different types of classical electromagnetic backgrounds. Assuming that the quantum field is in

Quantum field theory on incomplete manifolds

A theory of the scalar quantum field on static manifolds is constructed using the language of Feynman Green’s functions. By means of examples in which the manifolds are parts of Minkowski space, we

Stationary world lines and the vacuum excitation of noninertial detectors

The stationary world lines, on which quantized field detectors in a vacuum have time-independent excitation spectra, are discussed. They are characterized by the requirement that the geodetic

Physical interpretation of quantum field theory in noninertial coordinate systems.

In the upper and lower quadrants of flat spacetime, it is possible to introduce a system of coordinates in which the metric is explicitly time dependent, suggesting that quantum theory is covariant only for a subset of the coordinate transformations which are allowed in the classical theory.

On gauge invariance and vacuum polarization

This paper is based on the elementary remark that the extraction of gauge invariant results from a formally gauge invariant theory is ensured if one employs methods of solution that involve only