de Sitter space as a Glauber-Sudarshan state

Abstract Glauber-Sudarshan states, sometimes simply referred to as Glauber states, or alternatively as coherent and squeezed-coherent states, are interesting states in the configuration spaces of any quantum field theories, that closely resemble classical trajectories in space-time. In this paper, we identify four-dimensional de Sitter space as a coherent state over a supersymmetric Minkowski vacuum. Although such an identification is not new, what is new however is the claim that this is realizable in full string theory, but only in conjunction with temporally varying degrees of freedom and quantum corrections resulting from them. Furthermore, fluctuations over the de Sitter space is governed by a generalized graviton (and flux)-added coherent state, also known as the Agarwal-Tara state. The realization of de Sitter space as a state, and not as a vacuum, resolves many issues associated with its entropy, zero-point energy and trans-Planckian censorship, amongst other things.

Download Full-text

Four-dimensional de Sitter space is a Glauber-Sudarshan state in string theory

Journal of High Energy Physics ◽

10.1007/jhep07(2021)114 ◽

2021 ◽

Vol 2021 (7) ◽

Author(s):

Suddhasattwa Brahma ◽

Keshav Dasgupta ◽

Radu Tatar

Keyword(s):

String Theory ◽

Coherent State ◽

Degrees Of Freedom ◽

Vacuum Energy ◽

De Sitter Space ◽

The Other ◽

Quantum Corrections ◽

De Sitter ◽

Other Hand

Abstract We show that four-dimensional de Sitter space is a Glauber-Sudarshan state, i.e. a coherent state, over a supersymmetric solitonic background in full string theory. We argue that such a state is only realized in the presence of temporally varying degrees of freedom and after including quantum corrections, with supersymmetry being broken spontaneously. On the other hand, fluctuations over the resulting de Sitter space is governed by the Agarwal-Tara state, which is a graviton (and flux)-added coherent state. Once de Sitter space is realized as a coherent state, and not as a vacuum, its ability to remain out of the swampland as well as issues regarding its (meta)stability, vacuum energy, and finite entropy appear to have clear resolutions.

Download Full-text

On the Use of Quantum Thermal Bath in Unimolecular Fragmentation Simulations

10.26434/chemrxiv.8870594.v2 ◽

2019 ◽

Author(s):

Riccardo Spezia ◽

Hichem Dammak

Keyword(s):

Degrees Of Freedom ◽

Molecular Simulations ◽

Zero Point ◽

Thermal Bath ◽

Unimolecular Dissociation ◽

Point Energy ◽

Rotational Degrees Of Freedom ◽

The Difference ◽

Nuclear Effects

<div> <div> <div> <p>In the present work we have investigated the possibility of using the Quantum Thermal Bath (QTB) method in molecular simulations of unimolecular dissociation processes. Notably, QTB is aimed in introducing quantum nuclear effects with a com- putational time which is basically the same as in newtonian simulations. At this end we have considered the model fragmentation of CH4 for which an analytical function is present in the literature. Moreover, based on the same model a microcanonical algorithm which monitor zero-point energy of products, and eventually modifies tra- jectories, was recently proposed. We have thus compared classical and quantum rate constant with these different models. QTB seems to correctly reproduce some quantum features, in particular the difference between classical and quantum activation energies, making it a promising method to study unimolecular fragmentation of much complex systems with molecular simulations. The role of QTB thermostat on rotational degrees of freedom is also analyzed and discussed. </p> </div> </div> </div>

Download Full-text

ON DETERMINATION OF THE GEOMETRIC COSMOLOGICAL CONSTANT FROM THE OPERA EXPERIMENT OF SUPERLUMINAL NEUTRINOS

Modern Physics Letters A ◽

10.1142/s0217732312500411 ◽

2012 ◽

Vol 27 (11) ◽

pp. 1250041 ◽

Cited By ~ 4

Author(s):

MU-LIN YAN ◽

SEN HU ◽

WEI HUANG ◽

NENG-CHAO XIAO

Keyword(s):

Dark Energy ◽

Cosmological Constant ◽

Fundamental Constant ◽

Zero Point ◽

De Sitter Spacetime ◽

De Sitter ◽

Point Energy ◽

Sitter Spacetime ◽

Effective Cosmological Constant

The recent OPERA experiment of superluminal neutrinos has deep consequences in cosmology. In cosmology a fundamental constant is the cosmological constant. From observations one can estimate the effective cosmological constant Λ eff which is the sum of the quantum zero point energy Λ dark energy and the geometric cosmological constant Λ. The OPERA experiment can be applied to determine the geometric cosmological constant Λ. It is the first study to distinguish the contributions of Λ and Λ dark energy from each other by experiment. The determination is based on an explanation of the OPERA experiment in the framework of Special Relativity with de Sitter spacetime symmetry.

Download Full-text

LECTURE NOTES ON INTERACTING QUANTUM FIELDS IN DE SITTER SPACE

International Journal of Modern Physics D ◽

10.1142/s0218271814300018 ◽

2014 ◽

Vol 23 (01) ◽

pp. 1430001 ◽

Cited By ~ 74

Author(s):

E. T. AKHMEDOV

Keyword(s):

De Sitter Space ◽

The Self ◽

Field Theories ◽

Tree Level ◽

Main Concern ◽

Quantum Field Theories ◽

Quantum Field ◽

Quantum Fields ◽

De Sitter ◽

Invariant States

We discuss peculiarities of quantum fields in de Sitter (dS) space on the example of the self-interacting massive real scalar, minimally coupled to the gravity background. Nonconformal quantum field theories (QFTs) in dS space show very special infrared behavior, which is not shared by quantum fields neither in flat nor in anti-dS space: in dS space loops are not suppressed in comparison with tree level contributions because there are strong infrared corrections. That is true even for massive fields. Our main concern is the interrelation between these infrared effects, the invariance of the QFT under the dS isometry and the (in)stability of dS invariant states (and of dS space itself) under nonsymmetric perturbations.

Download Full-text

De Sitter entropy as holographic entanglement entropy

SciPost Physics Proceedings ◽

10.21468/scipostphysproc.4.002 ◽

2021 ◽

Author(s):

Nikolaos Tetradis

Keyword(s):

Effective Action ◽

Degrees Of Freedom ◽

Entanglement Entropy ◽

De Sitter Space ◽

Conformal Anomaly ◽

Dual Theory ◽

De Sitter ◽

Logarithmic Corrections ◽

Holographic Entanglement Entropy ◽

Gravitational Entropy

We review the results of refs. [1,2], in which the entanglement entropy in spaces with horizons, such as Rindler or de Sitter space, is computed using holography. This is achieved through an appropriate slicing of anti-de Sitter space and the implementation of a UV cutoff. When the entangling surface coincides with the horizon of the boundary metric, the entanglement entropy can be identified with the standard gravitational entropy of the space. For this to hold, the effective Newton's constant must be defined appropriately by absorbing the UV cutoff. Conversely, the UV cutoff can be expressed in terms of the effective Planck mass and the number of degrees of freedom of the dual theory. For de Sitter space, the entropy is equal to the Wald entropy for an effective action that includes the higher-curvature terms associated with the conformal anomaly. The entanglement entropy takes the expected form of the de Sitter entropy, including logarithmic corrections.

Download Full-text

A remark on alpha vacua for quantum field theories on de Sitter space

Journal of High Energy Physics ◽

10.1088/1126-6708/2005/05/063 ◽

2005 ◽

Vol 2005 (05) ◽

pp. 063-063 ◽

Cited By ~ 22

Author(s):

Romeo Brunetti ◽

Klaus Fredenhagen ◽

Stefan Hollands

Keyword(s):

De Sitter Space ◽

Field Theories ◽

Quantum Field Theories ◽

Quantum Field ◽

De Sitter

Download Full-text

A Hessian free method to prevent zero-point energy leakage in classical trajectory simulation

10.26434/chemrxiv-2022-53g43 ◽

2022 ◽

Author(s):

Saikat Mukherjee ◽

Mario Barbatti

Keyword(s):

Degrees Of Freedom ◽

Zero Point ◽

Classical Trajectory ◽

The Other ◽

Water Dimer ◽

Dynamics Simulation ◽

Zero Point Energy ◽

Point Energy ◽

Quantum Uncertainty ◽

Local Vibrational Mode

The problem associated with the zero-point energy (ZPE) leak in classical trajectory calculations is well known. Since ZPE is a manifestation of the quantum uncertainty principle, there are no restrictions on energy during the classical propagation of nuclei. This phenomenon can lead to unphysical results, such as forming products without the ZPE in the internal vibrational degrees of freedom (DOFs). The ZPE leakage also permits reactions below the quantum threshold for the reaction. We have developed a new Hessian-free method, inspired by the Lowe-Andersen thermostat model, to prevent energy dipping below a threshold in the local-pair (LP) vibrational DOFs. The idea is to pump the leaked energy to the corresponding local vibrational mode, taken from the other vibrational DOFs. We have applied the new correction protocol on the ab initio ground-state molecular dynamics simulation of the water dimer (H20)2, which dissociates due to unphysical ZPE spilling from the high-frequency OH modes. The LP-ZPE method has been able to prevent the ZPE spilling of the OH stretching modes by pumping back the leaked energy into the corresponding modes while this energy is taken from the other modes of the dimer itself, keeping the system as a microcanonical ensemble.

Download Full-text

New species of fermions and bosons, cosmological constant problem and a farewell to spin–statistics theorem

International Journal of Modern Physics D ◽

10.1142/s0218271821420311 ◽

2021 ◽

Author(s):

Dharam Vir Ahluwalia

Keyword(s):

Black Holes ◽

Dark Matter ◽

Degrees Of Freedom ◽

Zero Point ◽

Direct Argument ◽

Hierarchy Problem ◽

Cosmological Constant Problem ◽

Point Energy ◽

Net Zero ◽

Astronomical Time

If dark matter exists in the form of ultralight fermionic and bosonic species, then (a) it can accelerate evaporation of astrophysical black holes to the extent that their lifetimes can be reduced to astronomical time scales, a and (b) if there are extremely large number of such species it has the potential to solve the hierarchy problem [H. Davoudiasl, P. B. Denton and D. A. McGady, Phys. Rev. D 103 (2021) 055014; G. Dvali, Fortschr. Phys. 58 (2010) 528]. Here, we put forward a proposal that darkness of many of these new particles is natural, and in addition, the net zero point energy of the fermions exactly cancels that coming from the new bosons. The needed fermion–boson equality, and matching the fermion–boson degrees of freedom, comes about naturally. A very direct argument that allows the departure from the spin–statistics theorem is presented.

Download Full-text