[Paper Review] Hawking radiation via tachyon condensation and its implications to tachyon cosmology

Huiquan Li, Jiancheng Wang|arXiv (Cornell University)|Oct 29, 2013

Cosmology and Gravitation Theories28 references3 citations

TL;DR

This paper proposes that Hawking radiation arises from tachyon condensation on a probe D-particle falling into a non-extreme black hole, where the tachyon rolls toward the Hagedorn temperature, producing thermal radiation. This mechanism implies that uniform tachyon condensation in cosmology can naturally generate particle pairs and thermal perturbations, offering a novel reheating mechanism after tachyon inflation.

ABSTRACT

Hawking radiation can be derived from the collapsing process of matter to form a black hole. In this work, we show in more detail that the freely infalling process of a probe (D-)particle (or point-like object) in a non-extreme black hole background is essentially a tachyon condensation process. That is, a probe D-particle will behave as an unstable D-particle in the near-horizon region of a non-extreme black hole. From this point of view, Hawking radiation can be viewed as the thermal radiation from rolling tachyon on an unstable D-particle (i.e., the infalling probe) at the Hagedorn temperature. The result has interesting implications to tachyon cosmology: the uniform tachyon rolling in cosmology can automatically create particle pairs at late times, via a mechanism just like the Hawking radiation process near a black hole. So this particle creation process can naturally give rise to a hot universe with thermal perturbations beyond tachyon inflation, providing an alternative reheating mechanism.

Motivation & Objective

• To establish a connection between Hawking radiation and tachyon condensation in the context of D-particle dynamics near non-extreme black holes.
• To explore how the instability of a probe D-particle in a black hole background leads to thermal radiation via tachyon rolling.
• To investigate the cosmological implications of this mechanism, particularly in generating particle pairs and thermal perturbations after tachyon inflation.

Proposed method

• Model the infall of a probe D-particle into a non-extreme black hole as a tachyon condensation process in the near-horizon region.
• Analyze the tachyon dynamics on the unstable D-particle using effective field theory, identifying the rolling tachyon as the source of thermal radiation.
• Identify the Hagedorn temperature as the critical energy scale at which tachyon condensation leads to thermal emission.
• Extend the mechanism to cosmological settings by considering uniform tachyon condensation across spacetime.
• Derive the particle creation rate from the tachyon condensation process in cosmology, analogous to Hawking radiation near black holes.
• Demonstrate that this process naturally produces a hot universe with thermal perturbations, serving as an alternative reheating mechanism.

Experimental results

Research questions

• RQ1 How does the infall of a probe D-particle into a non-extreme black hole relate to tachyon condensation?
• RQ2 What is the role of the Hagedorn temperature in the thermal radiation process arising from tachyon rolling on an unstable D-particle?
• RQ3 Can the tachyon condensation mechanism near black holes be generalized to cosmological spacetimes?
• RQ4 Does uniform tachyon condensation in cosmology lead to spontaneous particle pair creation similar to Hawking radiation?
• RQ5 Can this process serve as a viable alternative to conventional reheating after tachyon inflation?

Key findings

• The freely falling probe D-particle in a non-extreme black hole background behaves as an unstable D-particle, undergoing tachyon condensation.
• Hawking radiation is interpreted as thermal radiation emitted during the tachyon condensation process on the unstable D-particle at the Hagedorn temperature.
• The tachyon condensation mechanism in cosmology naturally produces particle pairs at late times, mimicking the Hawking radiation process.
• This particle creation process results in a hot universe with thermal perturbations, providing a self-consistent reheating mechanism after tachyon inflation.
• The mechanism offers a novel, field-theoretic explanation for thermalization in early-universe cosmology without requiring external interactions.