TF1 Snowmass Report: Quantum gravity, string theory, and black holes

Harlow, Daniel; Kachru, Shamit; Maldacena, Juan; Bah, Ibou; Blake, Michael A.; Bousso, Raphael; Cvetič, Mirjam; Dong, Xiaoli; Engelhardt, Netta; Faulkner, Tom; Flauger, Raphael; Freed, Dan; Gorbenko, V.; Gu, Yingfei; Halverson, Jim; Hartman, Tom; Hartnoll, Sean A.; Karch, Andreas; Liu, Hong; Lucas, Andy; Martinec, Emil J.; McAllister, Liam; Moore, Gregory F.; Nekrasov, Nikita; Pasterski, Sabrina; Pate, Monica; Raclariu, Ana-Maria; Rajagopal, Krisha; Razamat, Shlomo; Shenker, Steve; Shafer-Nameki, Sakura; Shiu, Gary; Silverstein, Eva; Stanford, Douglas; Swingle, Brian; Taylor, Wati; Warner, Nicholas P.; Yoshida, Beni

doi:10.48550/arxiv.2210.01737

Cited by 7 publications

(7 citation statements)

References 45 publications

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“…Going deeper in possible field theory applications, an interesting arena would be classical and quantum gravity (see [25][26][27][28][29][30] for recent reports on the theoretical and experimental progress on quantum gravity, realized in the framework of the Snowmass 2021 study), for instance in the context of holography and conserved charges where soft mode dressing plays a very similar role to the wave-function higher moments [31]. An enticing line of research would be to tackle the problem of time 3 in quantum gravity, exploiting the intriguing possibility of a notion of intrinsic clock due to quantum degrees of freedom: we would look at the classical evolution of a system in terms of a clock built built from its own quantum fluctuations.…”

Section: Discussionmentioning

confidence: 99%

Quantum uncertainty as an intrinsic clock

Livine

2023

J. Phys. A: Math. Theor.

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In quantum mechanics, a classical particle is raised to a wave-function, thereby acquiring many more degrees of freedom. For instance, in the semi-classical regime, while the position and momentum expectation values follow the classical trajectory, the uncertainty of a wave-packet can evolve and beat independently. We use this insight to revisit the dynamics of a 1d particle in a time-dependent harmonic well. One can solve it by considering time reparameterizations and the Virasoro group action to map the system to the harmonic oscillator with constant frequency. We prove that identifying such a simplifying time variable is naturally solved by quantizing the system and looking at the evolution of the width of a Gaussian wave-packet. We further show that the Ermakov-Lewis invariant for the classical evolution in a time-dependent harmonic potential is actually the quantum uncertainty of a Gaussian wave-packet. This naturally extends the classical Ermakov-Lewis invariant to a constant of motion for quantum systems following Schrodinger equation. We conclude with a discussion of potential applications to quantum gravity and quantum cosmology.

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Section: Discussionmentioning

confidence: 99%

Quantum uncertainty as an intrinsic clock

Livine

2023

J. Phys. A: Math. Theor.

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“…In addition to the conformal anomaly, the second essential element needed for the formation of a gravastar is the ability of vacuum energy, or effective cosmological term Λ eff , to change rapidly at the horizon. The EFT that describes this quantum phase transition boundary layer at the horizon also provides a resolution of the 'naturalness' problem of Λ dark energy in cosmology [6,98,146]. That the physics of BHs is closely related to the 'fine tuning' issue of cosmological vacuum energy is inherent in the gravastar proposal, which requires a dynamical vacuum energy ρ V = 3H 2 /8πG in the dS interior to adjust to the total mass M of the gravastar to be joined at their mutual horizons H −1 = 2GM.…”

Section: Determination Of ε and For A Gravastarmentioning

confidence: 99%

Gravitational Vacuum Condensate Stars

Mottola¹

2023

Preprint

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Gravitational vacuum condensate stars, proposed as the endpoint of gravitational collapse consistent with quantum theory, are reviewed. Gravastars are cold, low entropy, maximally compact objects characterized by a surface boundary layer and physical surface tension, instead of an event horizon. Within this thin boundary layer the effective vacuum energy Λ eff changes rapidly, such that the interior of a non-rotating gravastar is a non-singular static patch of de Sitter space with eq. of state p = −ρ. Remarkably, essentially this same result is obtained by extrapolating Schwarzschild's 1916 constant density interior solution to its compact limit, showing how the black hole singularity theorems and the Buchdahl compactness bound are evaded. The surface stress tensor on the horizon is determined by a modification of the Lanczos-Israel junction conditions for null hypersurfaces, which is applied to rotating gravastar solutions as well. The fundamental basis for the quantum phase transition at the horizon is the stress tensor of the conformal anomaly, depending upon a new light scalar field in the low energy effective action for gravity. This scalar conformalon field allows the effective value of the vacuum energy, described as a condensate of an exact 4-form abelian gauge field strength F = dA, to change at the horizon. The resulting effective theory thus replaces the fixed constant Λ of classical general relativity, and its apparently unnaturally large sensitivity to UV physics, with a dynamical condensate whose ground state value in empty flat space is Λ eff = 0 identically. This provides both a natural resolution of the cosmological constant problem and an effective Lagrangian dynamical framework for the boundary layer and interior of gravitational vacuum condensate stars. The status of present observational constraints and prospects for detection of gravastars through their gravitational wave and echo signatures are discussed.

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“…Superstrings provide us with a quantum theory of gravity. Strictly speaking, this does not rule out the fact that the actual microscopic dynamics general relativity emerges from in the real world might be different from the one described by superstring theory, nor it implies that every question concerning the nature, behaviour and non-perturbative features of space-time in such a framework has received a satisfying answer [146][147][148][149][150][151][152][153]. In contemporary research, the attempts at addressing some of the issues related to the fundamental properties of quantum gravity from the perspective of strings has produced numerous groundbreaking results, as those related to the cobordism conjecture [154][155][156][157][158][159][160][161][162].…”

Section: Swampland Conjecturesmentioning

confidence: 99%

Geometric Flow of Bubbles

De Biasio,

Lust

2022

Preprint

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In this work we derive a class of geometric flow equations for metric-scalar systems. Thereafter, we construct them from some general string frame action by performing volume-preserving fields variations and writing down the associated gradient flow equations. Then, we consider some specific realisations of the above procedure, applying the flow equations to non-trivial scalar bubble and metric bubble solutions, studying the subsequent flow behaviour.

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TF1 Snowmass Report: Quantum gravity, string theory, and black holes

Abstract: We give an overview of the field of quantum gravity, string theory and black holes summarizing various white papers in this subject that were submitted as part of the Snowmass process.

Cited by 7 publications

References 45 publications

Quantum uncertainty as an intrinsic clock

Quantum uncertainty as an intrinsic clock

Gravitational Vacuum Condensate Stars

Geometric Flow of Bubbles

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