Article
Physics, Particles & Fields
Ralph Blumenhagen, Christian Kneissl, Andriana Makridou
Summary: Under certain assumptions, the quantum break time approach and the trans-Planckian censorship conjecture both result in de Sitter swampland constraints of the same functional form. By analyzing the consequences of quantum breaking, we find that there are implications for the thermal matter component and recover the no eternal inflation bound in the low temperature regime. Additionally, the stronger bound from the dS swampland conjecture can be obtained under reasonable assumptions about the high-temperature regime of string theory.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Astronomy & Astrophysics
Cesar Gomez, Raul Jimenez
Summary: In this article, the previous work on how the underlying primordial scaling law is implemented in the dS quantum Fisher information is summarized. The results show that, without any qdS input, the value of the spectral index ns is determined to be 0.9672 at large scales, and a small running value is predicted that is compatible with current experimental results.
PHYSICS OF THE DARK UNIVERSE
(2022)
Article
Astronomy & Astrophysics
Mehrdad Mirbabayi
Summary: By tracing out the environment systematically, we demonstrated the thermalization of out-of-equilibrium states of a light scalar field in a Markovian fashion as perceived by realistic observers. Using the results of Starobinsky and Yokoyama as a case study, we calculated the O(lambda) correction to the relaxation exponents of the lambda phi(4) theory.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Scott Bassler, Jack Laiho, Marc Schiffer, Judah Unmuth-Yockey
Summary: By studying the emergence of de Sitter space in Euclidean dynamical triangulations (EDT), researchers were able to relate lattice parameters to the partition function of Euclidean quantum gravity. Through simulations, they extracted a value of the renormalized Newton's constant, consistent with previous determinations from scalar particle interactions. The presence of the same universal constant in different sectors of the theory suggests that EDT may offer a viable formulation of quantum gravity.
Article
Physics, Multidisciplinary
Jose Manuel Penin, Kostas Skenderis, Benjamin Withers
Summary: In this study, we investigate the properties of strongly coupled mass-deformed CFT on a fixed de Sitter spacetime using holography. We elucidate the causal structure of the four-dimensional spacetime dual to the de Sitter invariant vacuum state and compute the correlation functions of the deformed-CFT stress tensor and scalar operator at each order of the mass deformation.
Article
Quantum Science & Technology
Frank Zhigang Wang
Summary: This study demonstrated that Landauer's bound can be quantitatively broken by extracting a single spin, and that the quantum limit is the key factor governing the performance of a spin qubit. An optically-manipulated spin-encoded quantum computer was designed to erase a spin qubit at a low energy bound well below k(B)T, which was theoretically reasonable and experimentally verified.
QUANTUM INFORMATION PROCESSING
(2022)
Article
Physics, Multidisciplinary
Anxo Biasi, Oleg Evnin, Spyros Sypsas
Summary: Cosmological acceleration is difficult to explain in theories involving supergravity and superstrings, but it is possible in theories with regular black holes. By placing this scenario in a global antide Sitter background, the formation of de Sitter bubbles can be enhanced, potentially leading to the creation of multiple accelerating universes. Numerical work in a two-dimensional dilaton-gravity model supports this idea.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Particles & Fields
Lulu Xiao, Cuihong Wen, Jiliang Jing, Jieci Wang
Summary: The study shows that the state between separated open charts can be used as a probe for black-box quantum metrology in de Sitter space, and the mass of the scalar field significantly affects the accuracy of parameter estimation. Quantum discord serves as a key resource for estimating the expanding parameter when there is no entanglement between initially uncorrelated open charts.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Physics, Particles & Fields
Daniele Teresi
Summary: In this study, the fine-grained entropy after inflation is analyzed using semiclassical calculations, and it is found to follow a Page-like curve. This suggests that the semiclassical expectation may need to be modified in the case of 2D gravity, and the entropy bound may not actually exist.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
Viacheslav A. Emelyanov
Summary: The study focuses on a coordinate-independent wave-packet solution of the massive Klein-Gordon equation with the conformal coupling to gravity in the de-Sitter universe. The solution is related to the two-point function in the de-Sitter quantum vacuum and the wave-packet propagation over cosmological times depending on the ratio of M and H. It is found that the wave packet behaves non-classically if M is not much larger than H, but propagates like a point-like particle of the same mass if M is significantly greater than H.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Multidisciplinary Sciences
Gia Dvali
Summary: The S-matrix formulation of gravity excludes de Sitter vacua, especially in the context of string theory, due to the anomalous quantum break-time enforced by the inverse values of gravitational and/or string couplings. De Sitter vacua can only be valid at the expense of trivializing the graviton and closed-string S-matrices. Additionally, observational signatures and the effects of particle species on quantum imprints are discussed, particularly in theories with a large number of species.
Article
Physics, Multidisciplinary
Ran Li, Zi-Han Yu, Shu-Zheng Yang
Summary: Based on the Lorentz symmetry breaking and black hole quantum tunneling radiation theory, this study modifies the Hawking temperature and black hole entropy of the NUT-Kerr-Newman-de Sitter black hole with general stationary characteristics, and deeply discusses the method used and the significance of the conclusions.
Article
Astronomy & Astrophysics
Ivano Basile, Alessia Platania
Summary: By utilizing the functional renormalization group and constraints of T-duality, we have derived cosmological effective actions to all orders in alpha', avoiding truncations of the theory space. Our findings show that higher-derivative alpha' corrections prohibit the existence of de Sitter vacua, supporting the no-de Sitter swampland conjecture in the presence of all-order effects in alpha'.
Article
Astronomy & Astrophysics
Llorenc Espinosa-Portales, Vincent Vennin
Summary: This study constructs Bell operators for quantum fields in real space and computes their expectation values for Gaussian states in terms of field power spectra. Applying the formalism to a scalar field in de-Sitter space-time, it is found that Bell inequalities are not violated in real space despite the generation of entangled particles on large scales. This is attributed to the implicit tracing over the field configurations at other locations, leading to effective decoherence and the erasure of quantum features.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Harry Goodhew
Summary: This paper proves that the wavefunction coefficients are rational based on a set of assumptions, and generalizes the manifestly local test to higher dimensions. This greatly reduces the allowed space of functions that wavefunction coefficients can take in both the Effective Field Theory of Inflation and Pure Gravity models, and is thus a key ingredient in the Cosmological Bootstrap program.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Gia Dvali, Sebastian Zell
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2018)
Article
Astronomy & Astrophysics
Gia Dvali, Lukas Eisemann, Marco Michel, Sebastian Zell
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2019)
Article
Quantum Science & Technology
Gia Dvali, Marco Michel, Sebastian Zell
EPJ QUANTUM TECHNOLOGY
(2019)
Article
Astronomy & Astrophysics
Mikhail Shaposhnikov, Andrey Shkerin, Sebastian Zell
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2020)
Article
Astronomy & Astrophysics
Mikhail Shaposhnikov, Andrey Shkerin, Inar Timiryasov, Sebastian Zell
Summary: The study focuses on inflation driven by the Higgs field in the Einstein-Cartan formulation of gravity, finding that inflation is possible and consistent with observations for a broad range of parameters. The results show that the spectral index is typically given by n(s) = 1-2/N-* and the tensor-to-scalar ratio r can vary between about 10(-10) and 1. This suggests the potential detection of gravitational waves from inflation in certain scenarios of Higgs inflation in the Einstein-Cartan framework.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Multidisciplinary
Mikhail Shaposhnikov, Andrey Shkerin, Inar Timiryasov, Sebastian Zell
Summary: This passage discusses a novel mechanism for producing singlet fermions in the early Universe through gravity-induced interactions. These fermions can act as dark matter particles and are applicable to a wide range of dark matter particle masses. The potential observational consequences of producing keV-scale dark matter in this way, particularly for right-handed neutrinos, are also explored. The authors suggest that determining the momentum distribution of primordial dark matter may shed light on gravity-induced fermionic interactions.
PHYSICAL REVIEW LETTERS
(2021)
Article
Computer Science, Interdisciplinary Applications
Marco Michel, Sebastian Zell
Summary: TimeEvolver is a program that computes time evolution in a quantum system using Krylov subspace techniques. It provides a rigorous error bound and adjustable precision for computing the exponential of a large sparse matrix with an initial vector.
COMPUTER PHYSICS COMMUNICATIONS
(2022)
Article
Physics, Particles & Fields
Georgios K. Karananas, Mikhail Shaposhnikov, Sebastian Zell
Summary: In this paper, we investigate the cutoff energy scale at which perturbation theory breaks down in inflation driven by the Higgs field coupled non-minimally to gravity. Using the metric formulation, we present a new method to calculate a lower bound on the cutoff, which does not rely on a gauge choice or require amplitude calculations. Instead, we exploit the invariance of the S-matrix under field redefinitions. Consistent with previous findings, we demonstrate that the cutoff during inflation is significantly higher than in vacuum, ensuring the reliability of semiclassical predictions. Additionally, we generalize our results to the Palatini formulation and discuss a useful parameterization of the Higgs doublet in both scenarios.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Astronomy & Astrophysics
Claire Rigouzzo, Sebastian Zell
Summary: The paper provides an overview of different formulations of general relativity (GR) and focuses on metric-affine gravity. It introduces an action of a scalar field coupled nonminimally to gravity within this framework. By eliminating nonpropagating degrees of freedom, an equivalent theory in the metric formulation of GR is derived. The paper concludes with a brief outlook on implications for Higgs inflation.
Article
Astronomy & Astrophysics
Georgios K. Karananas, Mikhail Shaposhnikov, Andrey Shkerin, Sebastian Zell
Summary: The article explores how Einstein-Cartan gravity can accommodate both global scale and local scale (Weyl) invariance, constructing a wide class of models with nonpropagating torsion and a nonminimally coupled scalar field. It discusses the need for an additional field-dilaton-for global scale invariance, and how the theory reduces to a subclass of one-field models in the case of the Weyl symmetry. The article also derives an equivalent metric theory in both scenarios of scale invariance and discusses possible implications for phenomenology.
Article
Astronomy & Astrophysics
Georgios K. Karananas, Mikhail Shaposhnikov, Andrey Shkerin, Sebastian Zell
Summary: The study explores the coupling of scalar, fermionic, and gauge fields to gravity in the Einstein-Cartan framework. It introduces a wide class of models without dynamical torsion, leading to a gravitational spectrum consisting of only the massless graviton. By eliminating nonpropagating degrees of freedom, an equivalent theory in the metric formulation of gravity is derived, featuring contact interactions between matter and gauge currents in a specific form. Additionally, the inclusion of curvature-squared terms is briefly discussed.
Article
Astronomy & Astrophysics
Mikhail Shaposhnikov, Andrey Shkerin, Sebastian Zell
Summary: The proposed model combines the Standard Model with gravity by utilizing nonminimal coupling and the Palatini formulation. It achieves electroweak symmetry breaking and incorporates inflation without introducing additional degrees of freedom beyond the SM and graviton. By relating inflationary parameters to collider experiment data, it addresses the hierarchy problem and opens up the possibility of calculating the Higgs mass.
Article
Physics, Particles & Fields
M. Shaposhnikov, A. Shkerin, I. Timiryasov, S. Zell
JOURNAL OF HIGH ENERGY PHYSICS
(2020)
Article
Astronomy & Astrophysics
Gia Dvali, Lukas Eisemann, Marco Michel, Sebastian Zell