Article
Astronomy & Astrophysics
Jarah Evslin, Hengyuan Guo
Summary: This study presents the two-loop kink mass and ground state construction in a scalar field theory, utilizing a simplified calculation method and eliminating the need for regulator matching conditions. The use of a coherent state operator and a perturbative fixed kink momentum greatly simplifies the process.
Article
Physics, Particles & Fields
Kimmo Kainulainen, Olli Koskivaara
Summary: The study analyzes the dynamical evolution of the one- and two-point functions of a scalar field in the 2PI framework under the Hartree approximation, highlighting the role of the effective potential in a non-equilibrium system and the non-perturbative processes during the reheating stage. By simulating the decay and thermalization of the scalar field, important results were identified.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Astronomy & Astrophysics
I. Jubb
Summary: In relativistic quantum field theory, ideal measurements can violate causality. Therefore, it is necessary to establish a condition that ensures causality in real scalar QFT. By studying unitary 'kicks' and Kraus operators, it is found that only smeared fields and the identity are causal observables.
Article
Astronomy & Astrophysics
Erik J. Gustafson
Summary: In this study, a gauge invariant digitization method for scalar quantum electrodynamics in (1 + 1)d with arbitrary spin truncation for qudit-based quantum computers is presented. The construction of the Trotter operator using a universal qudit-gate set is provided. The cost savings and feasibility of simulating a simple initial state on current qutrit-based hardware using noisy simulations are demonstrated.
Article
Physics, Particles & Fields
A. A. Radovskaya, A. G. Semenov
Summary: The study shows that the standard Keldysh-Schwinger diagram technique and the semiclassical expansion coincide when the coupling constant g and the Plank constant are simultaneously small. Additionally, by discussing loop diagrams of the perturbative approach and introducing a new technique, the research unifies both semiclassical and diagrammatic approaches. This opens up the possibility to perform the resummation of the semiclassical contributions.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Physics, Particles & Fields
Simon Woodward, Paul M. Saffin, Zong-Gang Mou, Anders Tranberg
Summary: In this paper, we apply the Generalised Thimble approach to compute exact path integrals and correlators in real-time quantum field theory. We investigate the numerical implementation and algorithm optimization in detail, and then apply the method to an interacting two-field system in 0+1 dimensions, demonstrating the potential of using real-time Generalised Thimble computations to address realistic physical processes.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
Seishi Enomoto, Tomohiro Matsuda
Summary: Using the exact WKB analysis of higher-order differential equations, we investigate the asymmetry in dynamical particle production of a complex scalar field. The solution involves the Stokes phenomena of a fourth-order differential equation. We discover that the interference between different types of Stokes phenomena leads to matter-antimatter asymmetry. Additionally, we demonstrate a specific case where asymmetry is prohibited in the exact calculation, but a spurious asymmetry arises in the perturbative expansion.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Astronomy & Astrophysics
Archie Cable, Arttu Rajantie
Summary: The stochastic approach to calculating scalar correlation functions in de Sitter spacetime has been extended beyond the overdamped slow-roll approximation. It reproduces the exact asymptotic long-distance behavior of field correlators in free field theory with the correct noise term, demonstrating the viability of the technique. However, the naive way of calculating the noise term by introducing a cutoff at the horizon does not give the correct answer unless the cutoff is specifically chosen to give the required result, which has implications for interacting theories.
Article
Physics, Particles & Fields
Valentin V. Khoze, Sebastian Schenk
Summary: At sufficiently high energies, the production of a large number of particles is allowed. However, in certain cases, the perturbative approach fails and an effective field theory is needed to describe the phenomena. By studying the effects of higher-dimensional operators in the effective field theory, we find that they contribute to an exponential growth factor.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Astronomy & Astrophysics
Marzieh Akbari Ahmadmahmoudi, Ehsan Bavarsad
Summary: The induced one-loop energy-momentum tensor of a massive complex scalar field in the presence of a uniform electric field on the two-dimensional de Sitter spacetime was studied in the framework of nonperturbative quantum electrodynamics. Coupling the scalar field directly to the Ricci scalar curvature with an arbitrary dimensionless nonminimal coupling constant was considered, and the trace anomaly of the induced energy-momentum tensor was evaluated. Results for the induced energy-momentum tensor and trace anomaly in the zero electric field case were shown to be consistent with existing literature, and the nonperturbative, regularized, one-loop effective Lagrangian of scalar QED in dS(2) was constructed from the induced energy-momentum tensor.
Article
Astronomy & Astrophysics
Muxin Han
Summary: An improved formulation of 4-dimensional Lorentzian spinfoam quantum gravity with a cosmological constant is presented, with finite spinfoam amplitudes and oscillatory terms in the semiclassical asymptotics of the vertex amplitude.
Article
Physics, Particles & Fields
Agnese Bissi, Parijat Dey, Jacopo Sisti, Alexander Soderberg
Summary: In this article, we study a class of two-point functions in a conformal field theory near a wedge. The set-up involves two boundaries intersecting at an angle theta, and we compute it as a solution to the Dyson-Schwinger equation of motion for a quartic interaction. We extract the anomalous dimensions from these correlators and complement the results with Feynman diagrams computations.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
Daniel Grimmer, Irene Melgarejo-Lermas, Jose Polo-Gomez, Eduardo Martin-Martinez
Summary: We demonstrate the use of machine learning techniques to overcome the challenges of designing experiments and interpreting the outcomes of quantum field measurements. Local measurements of quantum fields can reveal global features due to the local storage of global information in a scrambled way. By training neural networks, we can unscramble this information from data generated by a simple local measurement protocol. The framework proposed here can be applied to various local measurements on a quantum field to reveal its global properties in a standardized manner.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Astronomy & Astrophysics
Jan Ambjorn, Zbigniew Drogosz, Jakub Gizbert-Studnicki, Andrzej Gorlich, Jerzy Jurkiewicz, Daniel Nemeth
Summary: This article discusses the complex geometries extracted from the path integral of a quantum theory of gravity, showing that using suitable coordinate systems and scalar fields that solve Laplace's equation can help understand cosmic voids and filaments structures. It also demonstrates the dramatic changes in geometry that can occur when scalar fields are dynamically coupled to the geometry.
CLASSICAL AND QUANTUM GRAVITY
(2021)
Article
Physics, Particles & Fields
Oliver Gould
Summary: This study investigates the thermal phase transitions of a generic real scalar field without Z(2)-symmetry, exploring dimensional reduction and perturbative calculations to three-loop order, as well as lattice simulations. The reliability of perturbation theory decreases as the cubic coupling decreases relative to the quartic coupling, but the renormalisation group is shown to extend its validity. The research aims to offer a guide for similar calculations in other theories by making calculations as explicit as possible.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Georgios Katsianis, Ioannis Papadimitriou, Kostas Skenderis, Marika Taylor
Summary: The study provides a comprehensive analysis of supersymmetry anomalies in the Wess-Zumino model, discussing the anomalies and symmetry breaking caused by different multiplets of conserved currents. The research confirms the anomaly in Q-supersymmetry appearing in 4-point functions through explicit calculations and the action of regulators.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
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
Physics, Particles & Fields
Adam Bzowski, Paul McFadden, Kostas Skenderis
Summary: In this paper, we present a comprehensive discussion on the tree-level holographic 4-point functions of scalar operators in momentum space. We demonstrate that each Witten diagram satisfies the conformal Ward identities independently, making it a valid conformal correlator. Furthermore, we provide explicit formulas for evaluating Witten diagrams when certain conditions are met. Renormalization is necessary for these correlators and it leads to new conformal anomalies and beta functions. We also explore the idea of weight-shifting operators to link correlators of operators with different dimensions.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
Raffaele Marotta, Kostas Skenderis, Mritunjay Verma
Summary: We examined the 3-point CFT correlators involving non-conserved spinning operators in momentum space. A general expression for the conformal Ward identities defining the 3-point functions involving two generic spin s non-conserved operators and a spin 1 conserved current was derived. Explicit expressions for the 3-point function were provided when the two non-conserved operators have spins 1 and 2 and generic conformal dimensions. The divergences appearing in these 3-point functions when the conformal dimensions of the two non-conserved operators coincide were also systematically analyzed.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Astronomy & Astrophysics
J. M. Flynn, R. C. Hill, A. Juttner, A. Soni, J. T. Tsang, O. Witzel
Summary: Semileptonic Bs -Key decays are used to determine the CKM matrix element IVubI and investigate lepton-flavor -universality violations. Lattice QCD calculations are performed to obtain the decay form factors and their uncertainties. Combining with experimental measurements, the result for IVubI is determined to be 3.8(6) x 10-3. Rating: 8/10
Article
Astronomy & Astrophysics
Enrico Parisini, Kostas Skenderis, Benjamin Withers
Summary: We generalize the embedding space formalism to conformal field theories (CFTs) on nontrivial states and curved backgrounds using the ambient metric of Fefferman and Graham. The construction of CFT n-point functions in these settings is based on appropriate geometric invariants of the ambient space. Exact agreement with holographic computations and expectations from thermal operator product expansions (OPEs) is found for two-point functions of thermal CFT, and the method is also applied to CFTs on squashed spheres with no prior results available, demonstrating its utility.
Article
Astronomy & Astrophysics
Maximo Banados, Ernesto Bianchi, Ivan Munoz, Kostas Skenderis
Summary: We have developed a systematic procedure for renormalizing quantum field theories in anti-de Sitter spacetime. UV infinities are regulated using a geodesic point-splitting method, while IR infinities are regulated by cutting off the radial direction. We define the renormalized theory by introducing Z factors, boundary counterterm action, and renormalization conditions.
Article
Astronomy & Astrophysics
P. A. Boyle, F. Erben, J. M. Flynn, V. Gulpers, R. C. Hill, R. Hodgson, A. Juttner, F. O. Hogain, A. Portelli, C. T. Sachrajda
Summary: We perform the first calculation of the electromagnetic form factor V(z) for the long-distance contributions to the K+ -> pi+e+e- decay amplitude using physical light-quark masses. The calculation is done on a 2 + 1 flavor domain wall fermion ensemble with a lattice spacing of a-1 = 1.730(4) GeV. We implement a Glashow-Iliopoulos-Maiani cancellation by extrapolating to the physical charm-quark mass from three masses below charm. We obtain a value of V(z = 0.013(2)) = -0.87(4.44), providing a bound for its magnitude. The large statistical error is due to the stochastically estimated quark loops.
Article
Astronomy & Astrophysics
Aaron Poole, Kostas Skenderis, Marika Taylor
Summary: In this paper, we discuss the definition of conserved quantities in asymptotically locally de Sitter spacetimes. We introduce the analog of holographic charges at future and past infinity and at other Cauchy surfaces, and explain the characteristics and changes of these charges.
Article
Astronomy & Astrophysics
Luigi Del Debbio, Elizabeth Dobson, Andreas Juttner, Ben Kitching-Morley, Joseph K. L. Lee, Valentin Nourry, Antonin Portelli, Henrique Bergallo Rocha, Kostas Skenderis
Summary: A nonperturbative determination of the energy-momentum tensor is crucial in understanding strongly coupled systems. The Wilson flow method is utilized to renormalize the energy-momentum tensor for a three-dimensional massless scalar field with a phi(4) interaction in the adjoint of SU(N) on the lattice, including numerical results for the mixing coefficient in the N = 2 theory.
Article
Physics, Particles & Fields
Adam Bzowski, Paul McFadden, Kostas Skenderis
Summary: The general solution of the conformal Ward identities for scalar n-point functions in momentum space and general dimension is found, which involves integrals over (n - 1)-simplices. The correlators exhibit a recursive structure when the function of cross ratios is a monomial.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)