# Holographic cosmological model and thermodynamics on the horizon of the universe

March 26, 2020Kanazawa, Japan - The expansion of the Universe has occupied the minds of astronomers and astrophysicists for decades. Among the cosmological models that have been suggested over the years, Lambda cold dark matter (LCDM) models are the simplest models that can provide elegant explanations of the properties of the Universe, e.g., the accelerated expansion of the late Universe and structural formations. However, the LCDM model suffers from several theoretical difficulties, such as the cosmological constant problem. To resolve these difficulties, alternative thermodynamic scenarios have recently been proposed that extend the concept of black hole thermodynamics.

"Previous research implies that a certain type of universe will behave like an ordinary macroscopic system. The expansion of the Universe is considered likely to be related to thermodynamics on its horizon, based on the holographic principle," explains the study's author, Kanazawa University's Nobuyoshi Komatsu.

"I considered a cosmological model with a power-law term, assuming application of the holographic equipartition law. The power-law term is proportional to

*H*, where

^{α}*H*is the Hubble parameter and

*α*is considered to be a free parameter (

*α*may be related to the entanglement of the quantum fields close to the horizon)."

"I used the proposed model to study the thermodynamic properties on the horizon of the Universe, focusing on the evolutions of the Bekenstein-Hawking entropy. I found that the model satisfies the second law of thermodynamics on the horizon," says Associate Professor Komatsu.

"In addition, I used the model to examine the relaxation-like processes that occur before the last stage of the evolution of the Universe and thus enable study of the maximization of the entropy."

"Figure 1 shows the boundaries for maximization of the entropy in the (

*α*, ψ) plane. Here, ψ represents a type of density parameter for the effective dark energy. The upper side of each boundary corresponds to the region that satisfies the conditions for maximization of the entropy. For example, the point for the fine-tuned LCDM model is found to satisfy the conditions for maximization of the entropy at the present time. In addition, the region close to this point also satisfies the conditions for maximization of the entropy, both at the present time and in the future. Cosmological models in this region are likely to be favored from a thermodynamics viewpoint," says Associate Professor Komatsu.

In addition to the reported results of the study, it is hoped that the developed model will serve to enable discussion and analysis of the wide range of currently available cosmological models from a thermodynamics perspective.

-end-

Kanazawa University

## Related Thermodynamics Articles from Brightsurf:

New research explores the thermodynamics of off-equilibrium systems

Arguably, almost all truly intriguing systems are ones that are far away from equilibrium -- such as stars, planetary atmospheres, and even digital circuits.

Researchers discover a uniquely quantum effect in erasing information

Researchers from Trinity College Dublin have discovered a uniquely quantum effect in erasing information that may have significant implications for the design of quantum computing chips.

New model examines how societal influences affect US political opinions

Northwestern University researchers have developed the first quantitative model that captures how politicized environments affect U.S. political opinion formation and evolution.

Physicists build circuit that generates clean, limitless power from graphene

Physicists at the University of Arkansas have successfully generated an electrical current from the atomic motion of graphene, discovering a new source of clean, limitless power.

Theater improvisation techniques show promising results for science classroom engagement

A researcher at the University of Maryland, Baltimore County (UMBC) has developed a unique method to improve class participation in a graduate-level thermodynamics course by incorporating theater improvisation activities in the classroom.

Extracting order from a quantum measurement finally shown experimentally

In physics, it is essential to be able to show a theoretical assumption in actual, physical experiments.

Thermodynamics of computation: A quest to find the cost of running a Turing machine

Turing machines are widely believed to be universal, in the sense that any computation done by any system can also be done by a Turing machine.

Holographic cosmological model and thermodynamics on the horizon of the universe

A holographic cosmological model with a power-law term has been proposed by a Kanazawa University researcher to study thermodynamic properties on the horizon of the Universe.

APS tip sheet: Ultimate strength of metals

A new model is able to accurately determine the peak strength of polycrystalline metals.

How sensitive can a quantum detector be?

Measuring the energy of quantum states requires detecting energy changes so exceptionally small they are hard to pick out from background fluctuations, like using only a thermometer to try and work out if someone has blown out a candle in the room you're in.

Read More: Thermodynamics News and Thermodynamics Current Events

Arguably, almost all truly intriguing systems are ones that are far away from equilibrium -- such as stars, planetary atmospheres, and even digital circuits.

Researchers discover a uniquely quantum effect in erasing information

Researchers from Trinity College Dublin have discovered a uniquely quantum effect in erasing information that may have significant implications for the design of quantum computing chips.

New model examines how societal influences affect US political opinions

Northwestern University researchers have developed the first quantitative model that captures how politicized environments affect U.S. political opinion formation and evolution.

Physicists build circuit that generates clean, limitless power from graphene

Physicists at the University of Arkansas have successfully generated an electrical current from the atomic motion of graphene, discovering a new source of clean, limitless power.

Theater improvisation techniques show promising results for science classroom engagement

A researcher at the University of Maryland, Baltimore County (UMBC) has developed a unique method to improve class participation in a graduate-level thermodynamics course by incorporating theater improvisation activities in the classroom.

Extracting order from a quantum measurement finally shown experimentally

In physics, it is essential to be able to show a theoretical assumption in actual, physical experiments.

Thermodynamics of computation: A quest to find the cost of running a Turing machine

Turing machines are widely believed to be universal, in the sense that any computation done by any system can also be done by a Turing machine.

Holographic cosmological model and thermodynamics on the horizon of the universe

A holographic cosmological model with a power-law term has been proposed by a Kanazawa University researcher to study thermodynamic properties on the horizon of the Universe.

APS tip sheet: Ultimate strength of metals

A new model is able to accurately determine the peak strength of polycrystalline metals.

How sensitive can a quantum detector be?

Measuring the energy of quantum states requires detecting energy changes so exceptionally small they are hard to pick out from background fluctuations, like using only a thermometer to try and work out if someone has blown out a candle in the room you're in.

Read More: Thermodynamics News and Thermodynamics Current Events

Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.