Towards a unitary formulation of quantum field theory in curved space-time: the case of the Schwarzschild black hole

Sravan Kumar, João Marto

Research output: Contribution to journalArticlepeer-review

7 Downloads (Pure)

Abstract

We argue that the origin of unitarity violation and the information loss paradox in our understanding of black holes (BHs) lies in the standard way of doing quantum field theory in curved space-time (QFTCS), which is heavily biased on intuition borrowed from classical general relativity. In this paper, with the quantum-first approach, we formulate a so-called direct-sum QFT (DQFT) in BH space-time based on a novel formulation of discrete space-time transformations in gravity that potentially restores unitarity. By invoking the quantum effects associated with the gravitational backreaction, we show that the Hawking quanta emerging outside of the Schwarzschild radius (rs= 2GM⁠⁠) cannot be independent of the quanta that continue to be inside ⁠rs. This enables information to be carried by Hawking quanta, but in the BH DQFT formalism, we do not get any firewalls. Furthermore, DQFT leads to the BH evaporation involving only pure states. This means the quantum mechanical effects at the BH horizon produce two components of a maximally entangled pure state in geometric superselection sector Hilbert spaces. This construction enables pure states to evolve into pure states, restoring unitarity and observer complementarity. Finally, we discuss how our framework leaves important clues for formulating a scattering matrix and probing the nature of quantum gravity.
Original languageEnglish
Article number123E01
Pages (from-to)1-35
Number of pages35
JournalProgress of Theoretical and Experimental Physics
Volume2024
Issue number12
Early online date27 Nov 2024
DOIs
Publication statusPublished - 18 Dec 2024

Keywords

  • Quantum field theory on curved space
  • Quantum gravity
  • Black Holes
  • Hawking Radiation

Fingerprint

Dive into the research topics of 'Towards a unitary formulation of quantum field theory in curved space-time: the case of the Schwarzschild black hole'. Together they form a unique fingerprint.

Cite this