We study Parity Violating Gravity Theories whose gravitational Lagrangian is a generic function of the scalar curvature and the parity odd curvature pseudoscalar, commonly known as the Holst (or Hojmann) term. Generalizing some previous results in the literature, we explicitly show that if the Hessian of this function is non-degenerate, the initial non-Riemannian Theory is on-shell equivalent to a metric Scalar-Tensor Theory. The generic form of the kinetic coupling function and the scalar potential of the resulting Theory are explicitly found and reported.

Italy

Damianos Iosifidis

On the role of the parity violating Hojman–Holst term in gravity theories

In constructing quantum states at colliders, most efforts have focused on utilizing the particle decays to infer the spins to reconstruct the quantum density matrix. We show that the production kinematics of the particles provides sufficient information about the spins to establish quantum tomography event-by-event without using the decays. We lay out the advantages of using this “kinematic approach” relative to the usual “decay approach.” Since the kinematic approach leverages the simplicity of scattering kinematics, this approach promises to achieve optimal statistical results for quantum tomography at colliders.

United States

Kun Cheng

Tao Han

Matthew Low

Quantum tomography at colliders: With or without decays

In general yes, but also not quite. It is known that if the Bekenstein-Hawking entropy is replaced by some kind of generalized entropy, then the Bekenstein bound may be grossly violated. In this work, we show that this undesired violation can be avoided if we employ the equivalence between generalized entropy and varying- <italic>G</italic> gravity (GEVAG). In this approach, modifying entropy necessarily also modifies gravity (as one should expect if gravity is indeed inherently tied to thermodynamics), which leads to an effective gravitational &#8220;constant&#8221; <math altimg='si1.svg'><msub><mrow><mi>G</mi></mrow><mrow><mtext>eff</mtext></mrow></msub></math> that is area-dependent, and a thermodynamic energy that is distinct from the ADM mass. We show that a relaxed Bekenstein bound of the form <math altimg='si2.svg'><mi>S</mi><mo>&#10877;</mo><mi>C</mi><mi>R</mi><mi>E</mi></math> is always satisfied, albeit the coefficient <italic>C</italic> is no longer 2 <italic>&#960;</italic>.

China

Hengxin Lü

Yen Chin Ong

Do black holes with generalized entropy violate Bekenstein bound?

The “imaging-by-smashing” technique <cross-ref refid='br0010' id='crf0090'>[1]</cross-ref> has been developed recently in relativistic nuclear collisions. By smashing heavy nuclei at RHIC and the LHC and analysing the anisotropic expansion (flow) of the final state produced particles, unique information on the structure of the collided nuclei can be obtained. Existing efforts primarily focus on the colliding mode of heavy nuclei collisions. In contrast, nuclear structure studies with collisions of light nuclei and the fixed target mode have not been thoroughly explored despite their significant impact and broad interest. In this Letter, we investigate the nuclear structure of 20Ne and 16O in the fixed-target 208Pb&#8211; 20Ne and 208Pb&#8211; 16O collisions at <math altimg='si1.svg'><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><msub><mrow /><mrow><mi mathvariant='normal'>NN</mi></mrow></msub></mrow></msub></mrow></msqrt></math> = 68.5 GeV, using the parton transport model AMPT. The results of two- and four-particle cumulants of anisotropic flow demonstrate a robust signature of nuclear structure effect that persists regardless of the complex dynamic evolution of the created systems. The comparison to the recent hydrodynamic calculations reveals a new possibility of uncovering the origins of collective flow in small systems. This study highlights the significant impact of the light nuclei collisions at the LHCb SMOG (SMOG2) project.

Denmark

Zhiyong Lu

Mingrui Zhao

Emil Gorm Dahlbæk Nielsen

Xiaomei Li

You Zhou

Imprint of light nuclei structure in relativistic nuclear collisions

Radiative capture cross section strongly depends on the electromagnetic de-excitation probability, hence on the so-called photon strength function (PSF) and nuclear level density (NLD). Microscopic models for both PSF and NLD have been developed for the past decades but remain affected by fundamental assumptions, like the independent particle approximation for NLD and the assumption that the de-excitation PSF is equal to the photoabsorption PSF. The present study goes beyond the existing models by providing a common framework based on QRPA estimates of nuclear excitations that are used to derive NLD by coupling QRPA bosons as well as the de-excitation PSF by calculating all possible transition probabilities between QRPA states. The present framework is found to reproduce experimental data related to both NLD and PSF accurately, provided QRPA excitation energies are globally reduced by an energy-dependent shift. More specifically, the resulting NLDs, also extended to odd- <italic>A</italic> and odd-odd nuclei, are shown to be in good agreement with experimental s-wave resonance spacings and the photoabsorption PSF with photodata.

Belgium

S. Goriely

France

S. Péru

S. Hilaire

QRPA prediction of the nuclear level densities and de-excitation photon strength functions

We parametrically solve the Boltzmann equations (BEs) governing freeze-in dark matter (DM) in alternative cosmologies with Physics-Informed Neural Networks (PINNs), a mesh-free method. Through <italic>inverse</italic> PINNs, using a single DM experimental point &#8211; observed relic density &#8211; we determine the physical attributes of the theory, namely power-law cosmologies, inspired by braneworld scenarios, and particle interaction cross sections. The expansion of the Universe in such alternative cosmologies has been parameterized through a switch-like function reproducing the Hubble law at later times. Without loss of generality, we model more realistically this transition with a smooth function. We predict a distinct pair-wise relationship between power-law exponent and particle interactions: for a given cosmology with negative (positive) exponent, smaller (larger) cross sections are required to reproduce the data. Lastly, via Bayesian methods, we quantify the epistemic uncertainty of theoretical parameters found in <italic>inverse</italic> problems.

Portugal

M.P. Bento

H.B. Câmara

J.F. Seabra

Unraveling particle dark matter with Physics-Informed Neural Networks

We investigate the ternary fissions of 252Cf (spontaneous) and 236U (neutron-induced) into medium-mass fragments, as reported by the Dubna group, using the Hartree-Fock plus BCS method with the SLy6 Skyrme interaction. Compared to microscopic-macroscopic methods used so far, this self-consistent approach provides a greater flexibility of nuclear shapes.

Poland

Y. Jaganathen

J. Skalski

Suppression of genuine tripartition in heavy nuclei: A self-consistent perspective

J. Va’vra

Corrigendum to “A Simple Argument that Small Hydrogen May Exist” [ <italic>Physics Letters B</italic> Vol. 794, 2019, p. 130]

We study the fidelity of information retrieval in the black hole final state model by taking into account the interactions between the collapsing matter and the infalling Hawking radiation inside the event horizon. By utilizing a scrambling unitary operator to model these interactions, our direct calculations suggest that the information is almost lost during the process of black hole evaporation. We then proceed to employ the Yoshida-Kitaev decoding strategy for information retrieval. Although we observe a finite improvement in decoding fidelity, it does not reach unity. This indicates that the issue of unitarity in black hole evaporation may not be fully resolved within the framework of the final state model.

Ran Li

Jin Wang

On the fidelity of information retrieval in the black hole final state model with scrambling interactions

We investigate the essential properties of gravitational quantum field theory (GQFT) based on spin gauge symmetry, using the general theory of quantum electrodynamics as an example. A constraint equation for the field strength of the gravigauge field is derived, serving as a gravitization equation within the spin-related gravigauge spacetime. This equation reveals how gravitational effects emerge from the non-commutative relation of the gravigauge derivative operator. By transmuting the action from gravigauge spacetime to Minkowski spacetime, we demonstrate that translational invariance results in a vanishing energy-momentum tensor in GQFT when the equations of motion are applied to all fundamental fields, including the gravigauge field. This extends the conservation law of the energy-momentum tensor in quantum field theory to a cancellation law of the energy-momentum tensor in GQFT. As a result, an equivalence between the general gravitational equation and the zero energy-momentum tensor theorem naturally arises in GQFT. Certain aspects of the Poincaré gauge theory are also briefly discussed. Furthermore, a GQFT incorporating the Chern-Simons action in three-dimensional spacetime is developed, based on the inhomogeneous spin gauge symmetry WS(1,2) and the global Poincaré symmetry PO(1,2). This framework provides a basis for exploring its connection to Witten's perspective on three-dimensional gravity.

Yue-Liang Wu

Gravitization equation and zero energy momentum tensor theorem with cancellation law in gravitational quantum field theory