The quantum chromodynamics (QCD) phase structure has been studied using the Polyakov-loop augmented quark-meson model (PQM) in the extended mean field approximation (e-MFA), where the quark one-loop vacuum term is included. When the divergent vacuum term is regularized in the minimal subtraction scheme and the curvature meson masses are used to fix the parameters, the Polyakov quark-meson model with the vacuum term (PQMVT) becomes inconsistent as the curvature masses are determined by calculating the self energies at zero momentum. The above inconsistency is remedied by the on-shell parameter fixing when the pion decay constant and the pole masses of the mesons are put into the relation of the couplings and running mass parameter by using the on-shell and the minimal subtraction renormalization scheme. Combining the modified chiral effective potential of the on-shell renormalized quark-meson model (RQM) with the Polyakov-loop potential that mimics the physics of the confinement-deconfinement transition, we get the renormalized Polyakov quark-meson (RPQM) model. The phase diagrams and the thermodynamics details for the PQM, PQMVT, and RPQM model have been computed and compared for different forms of the Polyakov-loop potentials with and without the quark backreaction. The results have also been compared with the available lattice QCD data. The so-called quarkyonic phase region in the phase diagram, where the chiral symmetry is restored but the quarks and antiquarks are still confined, gets reduced by the quark backreaction in the unquenched Polyakov-loop potential. It altogether disappears for the chemical potential dependent parameter $T_0\equiv T_0(\mu )$ in the Log or the PolyLog-glue form of the Polyakov-loop potential in the RPQM model.

The recent discoveries and observations of pentaquarks and tetraquarks by high-energy accelerator facilities have accumulated evidence of the existence of multiquark hadrons with heavy quarks, as discussed from the early stage of the prediction of quarks. We construct a coupled-channel model for the hidden-charm pentaquarks with strangeness whose quark content is $udsc\overline{c}$, $P_{cs}$, described as ${\mathrm{\Lambda }}_c{\overline{D}}_s^{(*)}$, ${\mathrm{\Xi }}_c^{{(}^{\prime }*)}{\overline{D}}^{(*)}$ molecules, produced by the cooperation of the heavy quark and chiral symmetries, coupled to a five-quark core. We reproduce the experimental mass of $P_{cs}$, of which LHCb has announced the discovery. Furthermore, our result supports the quantum numbers that are preferred by the experiment. Our predictions indicate the existence of additional $P_{cs}$’s in proximity to molecular threshold regions, which can be further investigated by LHCb.

The Taub-NUT geometry corresponds to the Kaluza-Klein monopole solution of M-theory and on dimension reduction along the Taub-NUT circle direction it becomes the D6 brane of type IIA string theory. We show that the Taub-NUT geometry can be realized as a coherent state, or more appropriately as a Glauber-Sudarshan state in M-theory, once we take the underlying resurgence structure carefully. Using the duality chain it in turn implies that all D-branes as well as NS5-branes can be realized as Glauber-Sudarshan states in string theory. Our analysis also leads to an intriguing possibility of realizing the gravity duals of certain nonconformal minimally supersymmetric gauge theories by deforming a class of Glauber-Sudarshan states.

The decay of axionlike particles (ALPs) trapped in the solar gravitational field would contribute to the observed solar x-ray flux, hence constraining ALP models. We improve by one order of magnitude the existing limits in the parameter space $(g_{a\gamma \gamma },m)$ by considering ALPs production via photon coalescence. For $g_{ae}\ne 0$, we demonstrate that trapped ALPs can be Compton absorbed while crossing the Sun, resulting in two regimes in the exclusion limits, with a transition triggered by $g_{ae}$. Out of the transitional region, the solar x-ray constraints on ALPs are exclusively governed by $g_{a\gamma \gamma }$.

A recently proposed gedanken experiment involving the (gravitational or electromagnetic) interaction between two objects—one placed in a state of quantum superposition of two locations—seems to allow for faster-than-light communication. However, it has been argued that, if the mediating fields are endowed with quantum properties, then the possibility for superluminal signaling is fully avoided. Moreover, in the gravitational case, this conclusion has been used to argue for the view that the gravitational field must be quantized. In this work, we clarify and complement some aspects of the discussion. In particular, by focusing on the way in which entanglement spreads across the components of the system, we offer some insights into the fundamental quantum features behind the impossibility of superluminal signaling and we provide a more general proof of such an impossibility in this and related protocols.

We study the evolution of holographic subregion complexity (HSC) in a thermally and magnetically quenched, strongly coupled, quantum field theory in $2+1$ dimension. We illustrate two concepts of complexity in this theory: (1) how much information it takes to specify a state by studying the behavior of the final value of HSC in terms of the final temperature and magnetic field and (2) how long it takes to reach the state, by considering the time it takes for HSC to relax as a function of the final temperature and magnetic field. In the first concept, we observe that the effect of temperature and magnetic field on HSC decreases until the energy of the probe is comparable to the final temperature and magnetic field. We present an argument based on an ensemble of microstates corresponding to a given mixed macrostate. In the second concept, we show that the time of relaxation of HSC decreases with the increase of temperature and magnetic field for fixed values of the energy of the probe. We also compare the time evolution of HSC for two quenches in the first concept. We observe that the absolute value of the ratio of the final value of HSC for two kinds of quenches depends on the energy of the probe.

The sustained intense experimental activity around atomic spectroscopy and the resulting high-precision measurements of atomic spectral lines attracts interest in Lamb shift as a witness for noninertial effects in quantum systems. We investigate the Lamb shift in a two-level system, undergoing uniform circular motion, coupled to a quantum electromagnetic field inside a cavity. We show that when the separation between different cavity modes is large compared to the width of each cavity mode, both the inertial and purely noninertial contributions to the Lamb shift are convergent. In addition, we find that the purely noninertial Lamb shift maximizes away from the atomic resonance by an amount decided by the angular frequency of the circulating atom, lending itself to efficient enhancement by suitably tuning the cavity parameters. We argue that the purely noninertial contribution becomes detectable at accelerations $\sim {10}^{14}\mathrm{m}/{\mathrm{s}}^2$.

We consider a metric-affine extension to the gravitational sector of the Standard Model extension for the Lorentz-violating coefficients $u$ and $s^{\mu \nu }$. The general results, which are applied to a specific model called metric-affine bumblebee gravity, are obtained. A Schwarzschild-like solution, incorporating effects of the Lorentz symmetry breaking through the coefficient $X=\xi b^2$, is found. Furthermore, a complete study of the geodesic trajectories of particles is accomplished in this background, emphasizing the departure from general relativity. We also compute the advance of Mercury’s perihelion and the deflection of light within the context of the weak-field approximation, and we verify that there exist two new contributions ascribed to the Lorentz symmetry breaking. As a phenomenological application, we compare our theoretical results with observational data in order to estimate the coefficient $X$.

Reduced general relativity for four-dimensional spherically symmetric stationary space-times, more simply called the black hole minisuperspace, was shown in previous work to admit a symmetry under the three-dimensional Poincaré group $\mathrm{ISO}(2,1)$. Such a nonsemisimple symmetry group usually signals that the system is a special case of a more general model admitting a semisimple Lie group symmetry. We explore here possible modifications of the Hamiltonian constraint of the minisuperspace. We identify in particular a continuous deformation of the dynamics that lifts the degeneracy of the Poincaré group and leads to a $\mathrm{SO}(3,1)$ or $\mathrm{SO}(2,2)$ symmetry. This deformation is not related to the cosmological constant. We show that the deformed dynamics can be represented as the superposition of two noninteracting homogeneous Friedmann-Robertson-Walker cosmologies, with flat slices filled with perfect fluid. The resulting modified black hole metrics are found to be nonsingular.

Experiments are beginning to probe the interaction of quantum particles with gravitational fields beyond the uniform-field regime. In nonrelativistic quantum mechanics, the gravitational field in such experiments can be written as a superposition state. We empirically demonstrate that semiclassical theories of gravity can avoid gravitational superposition states only by decoupling the gravitational field energy from the quantum particle’s time evolution. Furthermore, such theories must specify a preferred quantum reference frame in which the equations of motion are valid. To the extent that these properties are theoretically implausible, recent experiments provide indirect evidence that gravity has quantum features. Proposed experiments with superposed gravitational sources would provide even stronger evidence that gravity is nonclassical.

We present a new effective-one-body (EOB) waveform for eccentric, nonspinning binaries in the extreme mass ratio limit, with initial eccentricities up to 0.95. The EOB analytical waveform, that includes noncircular corrections up to second post-Newtonian order, is completed by a phenomenological ringdown model that is informed by Regge-Wheeler-Zerilli (RWZ) type waveforms generated by a point-particle source. This model notably includes the beating between positive and negative frequency quasinormal modes (QNMs). We analyze various prescriptions to faithfully complete the analytical EOB waveform in the transition from plunge to merger. In particular, we systematically explore the effect of: (i) the generic Newtonian prefactor; (ii) next-to-quasicircular (NQC) corrections to amplitude and phase; (iii) the point where NQC corrections are determined; (iv) the ringdown attachment point. This yields EOB/RWZ quadrupolar phase differences through merger and ringdown $\lesssim 0.01\mathrm{rad}$ for the quasicircular case and $\lesssim 0.05\mathrm{rad}$ for the eccentric case. Higher modes are also modeled up to the $\ell =m=5$ multipole. We finally discuss the excitation of the QNMs and present a heuristic model to motivate it in correlation with the presence of a point-particle source.

We investigate the tidal forces exerted by a spherically symmetric static parametrized black hole. Our analysis reveals that the radial and angular components of the tidal forces exerted by the black hole can exhibit both positive and negative values near the black hole, depending on matters of the spacetime parameters. Unlike the scenario with the Schwarzschild black hole, where the radial tidal force (angular tidal force) is always stretching (compressing) and becomes infinite at the center of the spacetime, the parametrized black hole allows for finite and compressing (stretching) forces within the event horizon. Additionally, we derive the geodesic deviation equations for a particle in free fall and proceed to solve them through numerical methods. Our analysis demonstrates that the spacetime parameters $\epsilon$ and $a_1$ exhibit contrasting influences on the magnitudes of the physical quantities associated with tidal effects.

We present two solution-generating techniques, which are direct generalizations of certain Ehlers-Harrison transformations in the Ernst formalism, while adapted to work in presence of an anisotropic fluid source with axial symmetry. Based on these procedures, we were able to construct the electrically charged and the magnetized solution for any static axially symmetric geometry, which is sourced in general by an anisotropic fluid described by a nondiagonal anisotropic stress-energy tensor. As our main examples we derived and analyzed two new exact solutions with axial symmetry that describe the electrically charged Zipoy-Vorhees interior solution as well as the magnetized Zipoy-Vorhees interior solution, and presented some of their properties. As further examples of our solution-generating techniques we show how to derive two new solutions describing the electrically charged version of the Bowers and Liang solution, as well as a magnetized version of an exact solution with axial symmetry.

Massive objects located between Earth and a compact binary merger can act as gravitational lenses magnifying signals and improving the sensitivity of gravitational wave detectors to distant events. Depending on the parameters of the system, a point-mass lens between the detector and the source can either lead to a smooth frequency-dependent amplification of the gravitational wave signal, or magnification combined with the appearance of a second image that interferes with the first creating a regular, predictable pattern. We map the increase in the signal to noise ratio for upcoming LIGO-Virgo-KAGRA (LVK) observations as a function of the mass of the lens $M_L$ and a dimensionless source position $y$ for any point-mass lens between the detector and the binary source. To quantify detectability, we compute the optimal match between the lensed waveform and the waveforms in the unlensed template bank and provide a map of the match. The higher the mismatch with unlensed templates, the more detectable lensing is. Furthermore, we estimate the probability of lensing, and find that the redshift to which binary mergers are visible with the LVK increases from $z\approx 1$ to $z\approx 3.2$ for a total detected mass $M_{\det }=120M_{\odot }$. The overall probability of lensing is $<20\%$ of all detectable events above the threshold SNR for $M_{\det }=120M_{\odot }$ and $<5\%$ for more common events with $M_{\det }=60M_{\odot }$. We find that there is a selection bias for detectable lensing that favors events that are close to the line of sight $y\lesssim 0.5$. Black hole binary searches could thus improve their sensitivity by taking this bias into account. Moreover, the match, the signal-to-noise ratio increase due to lensing, and the probability of lensing are only weakly dependent on the noise curve of the detector with very similar results for both the O3 and predicted O4 noise power spectral densities. These results are upper limits that assume all dark matter is composed of $300M_{\odot }$ point-mass lenses.

To evaluate the probability of a gravitational-wave candidate originating from noise, GstLAL collects noise statistics from the data it analyzes. Gravitational-wave signals of astrophysical origin get added to the noise statistics, harming the sensitivity of the search. We present the background filter, a novel tool to prevent this by removing noise statistics that were collected from gravitational-wave candidates. To demonstrate its efficacy, we analyze one week of LIGO and Virgo O3 data, and show that it improves the sensitivity of the analysis by 20%–40% in the high mass region, in the presence of 868 simulated gravitational-wave signals. With the upcoming fourth observing run of LIGO, Virgo, and KAGRA expected to yield a high rate of gravitational-wave detections, we expect the background filter to be an important tool for increasing the sensitivity of a GstLAL analysis.

Invertible disformal transformations serve as a useful tool to explore ghost-free scalar-tensor theories. In this paper, we construct a generalization of invertible disformal transformations that involves arbitrary higher-order covariant derivatives of the scalar field. As a result, we obtain a more general class of ghost-free scalar-tensor theories than ever. Notably, our generalization is such that matter fields can be consistently coupled to these theories without introducing an unwanted extra degree of freedom in the unitary gauge.

We study the effects of reheating phase on the evolution of complexities for the primordial curvature perturbation using the squeezed formalism. We examine the evolution of the out-of-time correlator, the quantum discord, and circuit complexity, starting from the inflationary epoch to the radiation-dominated epoch with different reheating scenarios. We find that for a mode that reenters the horizon after reheating, the effect of a finite reheating epoch on the characteristic freeze-in amplitude of these primordial complexities can only be distinguished up to three different classes depending on whether the equation of state (EOS) parameter: (i) $w_{\mathrm{re}}=1/3$, (ii) $w_{\mathrm{re}}<1/3$, or (iii) $w_{\mathrm{re}}>1/3$. For reheating with different EOSs within these classes, the final amplitude will be the same—hence the detailed signature of reheating on the complexity measures, within a class, will be lost. Taking the central value of the scalar spectral index ($n_s=0.9649$) from Planck and the equation of state during reheating $w_{\mathrm{re}}=0.25$ as benchmark values, we found that the behavior of the complexities for all modes smaller than $1.27\times {10}^{16}{\mathrm{Mpc}}^{-1}$ can be classified as above. However, for the small-scale modes reentering the horizon during reheating, the signature of EOSs on the evolution of these complexities will be embedded in each of the cases separately.

A dynamical system analysis is performed for a model of dissipative quintessential inflation realizing warm inflation at early primordial times and dissipative interations in the dark sector at late times. The construction makes use of a generalized exponential potential realizing both phases of accelerated expansion. A focus is given on the behavior of the dynamical system at late times and the analysis is exemplified by both analytical and numerical results. The results obtained demonstrate the viability of the model as a quintessential inflation model in which stable solutions can be obtained.

Various weakly interacting massive particle (WIMP) dark matter searches using the full data set of XMASS-I, a single-phase liquid xenon detector, are reported in this paper. Stable XMASS-I data taking accumulated a total live time of 1590.9 days between November 20, 2013 and February 1, 2019 with an analysis threshold of $1.0{\mathrm{keV}}_{\mathrm{ee}}$. In the latter half of data taking a lower analysis threshold of $0.5{\mathrm{keV}}_{\mathrm{ee}}$ was also available through a new low threshold trigger. Searching for a WIMP signal in the detector’s 97 kg fiducial volume yielded a limit on the WIMP-nucleon scattering cross section of $1.4\times {10}^{-44}{\mathrm{cm}}^2$ for a $60\mathrm{GeV}/{\mathrm{c}}^2$ WIMP at the 90% confidence level. We also searched for WIMP induced annual modulation signatures in the detector’s whole target volume, containing 832 kg of liquid xenon. For nuclear recoils of a $8\mathrm{GeV}/{\mathrm{c}}^2$ WIMP this analysis yielded a 90% confidence level (CL) cross section limit of $2.3\times {10}^{-42}{\mathrm{cm}}^2$. Annual modulation signatures from the Migdal effect and bremsstrahlung at a WIMP mass of $0.5\mathrm{GeV}/{\mathrm{c}}^2$ are evaluated and lead to 90% CL cross section limits of $1.4\times {10}^{-35}{\mathrm{cm}}^2$ and $1.1\times {10}^{-33}{\mathrm{cm}}^2$, respectively.

In this work, we investigate the potential of gamma-ray pulsar time array (PTA) on gravitational wave background (GWB) using future gamma-ray detectors with larger effective areas. We consider both spaceborne detectors and ground-based imaging air Cherenkov telescope arrays (IACTs). We simulated the detected photons from pulsars using the response of hypothetical detectors taking into account the backgrounds and analyzed the sensitivities. Our results showed that thanks to the higher statistics of IACTs, the PTA using IACTs can improve significantly the performance compared with the PTA using Fermi-LAT data.