This work investigates in detail the performance and advantages of a new quantum Monte Carlo integrator, dubbed quantum Fourier iterative amplitude estimation (QFIAE), to numerically evaluate for the first time loop Feynman integrals in a near-term quantum computer and a quantum simulator. In order to achieve a quadratic speedup, QFIAE introduces a quantum neural network (QNN) that efficiently decomposes the multidimensional integrand into its Fourier series. For a one-loop tadpole Feynman diagram, we have successfully implemented the quantum algorithm on a real quantum computer and obtained a reasonable agreement with the analytical values. One-loop Feynman diagrams with more external legs have been analyzed in a quantum simulator. These results thoroughly illustrate how our quantum algorithm effectively estimates loop Feynman integrals and the method employed could also find applications in other fields such as finance, artificial intelligence, or other physical sciences.

Abstract: Exploring heavy vector mesons of the $J/\psi$ and $\mathrm{\Upsilon }(1S)$ is crucial for understanding the quark gluon plasma (QGP) formed in heavy ion collisions. The influences of rotational effect on the properties of the $J/\psi$ and the $\mathrm{\Upsilon }(1S)$ are investigated by incorporating rotation medium into the holographic QCD. It is found that temperature, chemical potential, and rotational radius effects enhance the dissociation process of the $J/\psi$ and the $\mathrm{\Upsilon }(1S)$ states within the medium. This rotation-induced effect is more significant for heavy vector mesons in the transverse direction than that of the longitudinal direction. The first holographic study on the influence of the radius of a homogeneous rotating system on the vector meson spectrum is proposed. It is found that increasing in rotation radius promotes the dissociation of vector mesons of the $J/\psi$ and $\mathrm{\Upsilon }(1S)$. We also find that the dissociation perpendicular to the direction of rotational angular velocity is more significant than that parallel to it at large rational radius.

In recent years, significant progress has been made in the study of integrable systems from a gauge theoretic perspective. This development originated with the introduction of four-dimensional Chern-Simons theory with defects, which provided a systematic framework for constructing two-dimensional integrable systems. In this article, we propose a novel approach to studying higher-dimensional integrable models employing techniques from higher category theory. Starting with higher Chern-Simons theory on the 4-manifold $\mathbb{R}\times Y$, we complexify and compactify the real line to $\mathbb{C}{P}^1$ and introduce the disorder defect $\omega =z^{-1}\mathrm{d}z$. This procedure defines a holomorphic five-dimensional variant of higher Chern-Simons theory, which, when endowed with suitable boundary conditions, allows for the localization to a three-dimensional theory on $Y$. The equations of motion of the resulting model are equivalent to the flatness of a 2-connection $(L,H)$, that we then use to construct the corresponding higher holonomies. We prove that these are invariants of homotopies relative boundary, which enables the construction of conserved quantities. The latter are labeled by both the categorical characters of a Lie crossed module and the infinite number of homotopy classes of surfaces relative boundary in $Y$. Moreover, we also demonstrate that the three-dimensional theory has left and right acting symmetries whose current algebra is given by an infinite-dimensional centrally extended affine Lie 2-algebra. Both of these conditions are direct higher homotopy analogs of the properties satisfied by the two-dimensional Wess-Zumino-Witten conformal field theory, which we therefore interpret as facets of integrable structures.

We investigate $T\overline{T}$ deformation on non-Hermitian coupled Sachdev-Ye-Kitaev (SYK) model and the holographic picture. The relationship between ground state and thermofield double state is preserved under the $T\overline{T}$ deformation. We prove that $T\overline{T}$ deformed theory provides a reparametrization in large $N$ limit. We numerically calculate the deformation effects on the correlation function in imaginary time and the free energy. The thermodynamic phase structures show the equivalence of the wormhole-black hole picture between non-Hermitian model and Hermitian model still holds under $T\overline{T}$ deformation. The correlation function in Lorentz time, revival dynamic, and the deformed holography are also evaluated.

We revisit the construction of the Hilbert space of nonrelativistic particles moving in three spatial dimensions. This is given by the space of sections of a line bundle that can in general be topologically nontrivial. Such bundles are classified by a set of integers—one for each pair of particles—and arise physically when we describe the interactions of dyons, particles which carry both electric and magnetic charges. The choice of bundle fixes the representation of the Euclidean group carried by the Hilbert space. These representations are shown to recover the “pairwise helicity” formalism recently discussed in the literature.

This paper collects several results in the study of the explicit symmetry-breaking limit of the effective-field theory (EFT) description of diffeomorphism and local Lorentz symmetry breaking, where we generalize a subset of the EFT framework (the “minimal” sector). It is well known that no-go constraints may arise in cases of explicit symmetry breaking in curved spacetime as a consequence of the Bianchi identities; we show in this work that certain terms in the action can be countenanced and used to cancel would-be no-go constraints, at least in the linearized gravity limit. Nonetheless, we go on to find more potential issues, and we show that one particular explicit breaking subset of the EFT, while evading direct no-go constraints, results in a discontinuity—unsuppressed additional polarizations for gravitational waves. In a general treatment of the explicit breaking EFT, but confined to linearized gravity, we explicitly show the existence of an extra degree of freedom, independent of coordinates. We find extra polarizations of gravitational waves in the solutions, with a scalar mode unsuppressed by any coefficient, which could render these cases ruled out by observations.

Gravitational wave observations of black hole-neutron star binaries, particularly those where the black hole has a lower mass compared to other observed systems, have the potential to place strong constraints on modifications to general relativity that arise at small curvature length scales. Here we study the dynamics of black hole-neutron star mergers in shift-symmetric Einstein-scalar-Gauss-Bonnet gravity, a representative example of such a theory, by numerically evolving the full equations of motion. We consider quasi-circular binaries with different mass-ratios that are consistent with recent gravitational wave observations, including cases with and without tidal disruption of the star, and quantify the impact of varying the coupling controlling deviations from general relativity on the gravitational wave signal and scalar radiation. We find that the main effect on the late inspiral is the accelerated frequency evolution compared to general relativity, and that—even considering Gauss-Bonnet coupling values approaching those where the theory breaks down—the impact on the merger gravitational wave signal is mild, predominately manifesting as a small change in the amplitude of the ringdown. We compare our results to current post-Newtonian calculations and find consistency throughout the inspiral.

We define the Carrollian black holes corresponding to the limit of Schwarzschild–(anti)de Sitter (A)dS black holes and its higher-derivative counterpart known as Schwarzschild-Bach-(A)dS black holes, which is also a static spherically symmetric vacuum solution of quadratic gravity. By analyzing the motion of massive particles in these geometries, we found that, in the case of Schwarzschild-(A)dS black hole, a (nearly) tangential particle from infinity will wind around the extremal surface with a finite number of windings depending on the impact parameter and the cosmological constant. In Schwarzschild-Bach-(A)dS black hole, a particle passing close enough to the extremal surface will have an infinite number of windings; hence, it will not escape to asymptotic infinity as in Schwarzschild-(A)dS black hole. We also calculate the thermodynamical quantities for such black holes and argue that it is analogous to an incompressible thermodynamical system with divergent entropy when the temperature goes to zero (in the strict Carroll limit). We then define a divergent specific heat that can be positive, negative, or zero.

We study detection prospects of a gravitational-wave background (GWB) sourced by SU(2) gauge fields considering all possible observational constraints. More precisely, we consider bounds set by cosmic microwave background measurements, primordial black hole overproduction, as well as backreaction of the gauge fields on the background evolution. Gravitational-waves data from the first three observing runs of the LIGO-Virgo-KAGRA Collaboration show no evidence for a GWB contribution from axion inflation. However, we are able to place conservative constraints on the parameters of the SU(2) inflation with current data. We investigate conditions on the inflationary potential that would lead to a detectable signal that evades astrophysical and cosmological constraints and discuss detection prospects for third generation networks.

Discontinuous Galerkin (DG) methods for solving elliptic equations are gaining popularity in the computational physics community for their high-order spectral convergence and their potential for parallelization on computing clusters. However, problems in numerical relativity with extremely stretched grids, such as initial data problems for binary black holes that impose boundary conditions at large distances from the black holes, have proven challenging for DG methods. To alleviate this problem we have developed a primal DG scheme that is generically applicable to a large class of elliptic equations, including problems on curved and extremely stretched grids. The DG scheme accommodates two widely used initial data formulations in numerical relativity, namely the puncture formulation and the extended conformal thin-sandwich (XCTS) formulation. We find that our DG scheme is able to stretch the grid by a factor of $\sim {10}^9$ and hence allows to impose boundary conditions at large distances. The scheme converges exponentially with resolution both for the smooth XCTS problem and for the nonsmooth puncture problem. With this method we are able to generate high-quality initial data for binary black hole problems using a parallelizable DG scheme. The code is publicly available in the open-source spectre numerical relativity code.

We consider three cosmological models with non-power-law spectra of primordial density perturbations and test them against $\mathrm{\Lambda }\mathrm{CDM}$ in density profiles of dark matter halos. We found that, despite the significant difference in initial conditions, the mean density profiles of all models are still close to the Navarro-Frenk-White one, albeit with some dispersion. We demonstrate that the density profile slopes in the innermost part of the halo have a significant evolution with $z$, which can be used to identify the cosmological model. We also present a toy model resulting in the appearance of core in the central part of the dark matter halo.

Year 1 results of the Legacy Survey of Space and Time (LSST) will provide tighter constraints on small-scale cosmology, beyond the validity of linear perturbation theory. This heightens the demand for a computationally affordable prescription that can accurately capture nonlinearities in beyond-$\mathrm{\Lambda }\mathrm{CDM}$ models. The comoving Lagrangian acceleration (COLA) method, a cost-effective $N$-body technique, has been proposed as a viable alternative to high-resolution $N$-body simulations for training emulators of the nonlinear matter power spectrum. In this study, we evaluate this approach by employing COLA emulators to conduct a cosmic shear analysis with LSST-Y1 simulated data across three different nonlinear scale cuts. We use the $w\mathrm{CDM}$ model, for which the euclidemulator2 (ee2) exists as a benchmark, having been trained with high-resolution $N$-body simulations. We primarily utilize COLA simulations with mass resolution $M_{\mathrm{part}}\approx 8\times {10}^{10}{h}^{-1}{M}_{\odot }$ and force resolution ${\ell }_{\text{force}}=0.5h^{-1}\mathrm{Mpc}$, though we also test refined settings with $M_{\mathrm{part}}\approx 1\times {10}^{10}{h}^{-1}{M}_{\odot }$ and force resolution ${\ell }_{\text{force}}=0.17h^{-1}\mathrm{Mpc}$. We find the performance of the COLA emulators is sensitive to the placement of high-resolution $N$-body reference samples inside the prior, which only ensure agreement in their local vicinity. However, the COLA emulators pass stringent criteria in goodness of fit and parameter bias throughout the prior, when existing high-resolution $\mathrm{\Lambda }\mathrm{CDM}$ emulators are leveraged alongside the COLA emulators to predict the respective $\mathrm{\Lambda }\mathrm{CDM}$ parameters, suggesting a promising template for extensions to $\mathrm{\Lambda }\mathrm{CDM}$.

In a class of modular-invariant models with multiple moduli fields, the viable lepton flavor mixing pattern can be realized if the values of moduli are selected to be at the fixed points. In this paper, we investigate a modulus stabilization mechanism in the multiple-modulus framework which is capable of providing de Sitter (dS) minima precisely at the fixed points $\tau =\mathrm{i}$ and $\omega$, by taking into consideration nonperturbative effects on the superpotential and the dilaton Kähler potential. Due to the existence of additional Kähler moduli, more possible vacua can occur, and the dS vacua could be the deepest under certain conditions. We classify different choices of vacua and discuss their phenomenological implications for lepton masses and flavor mixing.

We continue our investigation of the stress within a strongly coupled scalar nucleon, and now dissect the gravitational form factors into contributions from its constituents, the (mock) nucleon and the (mock) pion. The computation is based on a nonperturbative solution of the scalar Yukawa model in the light-front Hamiltonian formalism with a Fock sector expansion, including up to one nucleon and two pions. By employing the “good currents” $T_i^{++}$, $T_i^{+-}$ and $T_i^{12}$, we extract the full set of gravitational form factors $A_i$, $D_i$, ${\overline{c}}_i$ without the contamination of the spurious form factors and free of uncanceled UV divergences. With these results, we decompose the mass of the system into its constituents and compute the matter and mechanical radii, gaining insights into the strongly coupled system.

The relativistic degrees of freedom ($N_{\mathrm{eff}}$) is one of the crucial cosmological parameters. The precise measurement of $N_{\mathrm{eff}}$ at the time of cosmic microwave background formation, by Planck 2018 can be used to understand the new fundamental interactions, in particular involving light mediators. Presence of any new particle with sufficient energy density and sizeable interactions with Standard Model particles at the temperature around $\sim \mathrm{MeV}$ can significantly alter the neutrino decoupling and hence $N_{\mathrm{eff}}$. Thus the bound on $N_{\mathrm{eff}}$ can place stringent constraints on various beyond Standard Model paradigms involving light particles. $U(1{)}_X$ models are among such scenarios and are widely studied in several aspects. In this work, we consider several popular $U(1{)}_X$ models with light $Z^{\prime }$ boson like $U(1{)}_{B-L}$, $U(1{)}_{B-3L_i}$, $U(1{)}_{B_i-3L_j}$, $U(1{)}_{L_i-L_j}$; $i,j=1,2,3$ being the flavor indices and study their impact on $N_{\mathrm{eff}}$. We also examine the constraints from ground based experiments like Xenon1T, Borexino, trident, etc. Our analysis shows that for light mass $M_{Z^{\prime }}\lesssim \mathcal{O}(\mathrm{MeV})$ the $N_{\mathrm{eff}}$ provides the most stringent constraints on the $Z^{\prime }$ mass and coupling, far exceeding the existing constraints from other experiments.

In models featuring extra spatial dimensions, particle collisions in the early Universe can produce Kaluza-Klein gravitons. Such particles will later decay, potentially impacting the process of big bang nucleosynthesis. In this paper, we consider scenarios in which gravity is free to propagate throughout $n$ flat, compactified extra dimensions, while the fields of the Standard Model are confined to a ($3+1$)-dimensional brane. We calculate the production and decay rates of the states that make up the Kaluza-Klein graviton tower and determine the evolution of their abundances in the early Universe. We then go on to evaluate the impact of these decays on the resulting light element abundances. We identify significant regions of previously unexplored parameter space that are inconsistent with measurements of the primordial helium and deuterium abundances. In particular, we find that for the case of one extra dimension (two extra dimensions), the fundamental scale of gravity must be $M_{\star }\gtrsim 2\times {10}^{13}\mathrm{GeV}$ ($M_{\star }\gtrsim 10^{10}\mathrm{GeV}$) unless the temperature of the early Universe was never greater than $T\sim 2\mathrm{TeV}$ ($T\sim 1\mathrm{GeV}$). For larger values of $n$, these constraints are less stringent. For the case of $n=6$, for example, our analysis excludes all values of $M_{\star }$ less than $\sim {10}^6\mathrm{GeV}$, unless the temperature of the Universe was never greater than $T\sim 3\mathrm{TeV}$. The results presented here severely limit the possibility that black holes were efficiently produced through particle collisions in the early Universe’s thermal bath.

The nature of dark matter remains one of the greatest unsolved mysteries in elementary particle physics. It might well be that the dark matter particle belongs to a dark sector completely secluded or extremely weakly coupled to the visible sector. We demonstrate that gravitational waves arising from first-order phase transitions in the early Universe can be used to look for signatures of dark sector models connected to neutron physics. This introduces a new connection between gravitational-wave physics and nuclear physics experiments. Focusing on two particular extensions of the Standard Model with dark U(1) and SU(2) gauge groups constructed to address the neutron lifetime puzzle, we show how those signatures can be searched for in future gravitational-wave and astrometry experiments.

We provide a set of theoretical constraints on models in which the Standard Model field content is extended by vectorlike fermions and in some cases also by a real scalar singlet. Our approach is based on the study of electroweak vacuum stability, perturbativity of model couplings, and gauge couplings unification with the use of renormalization group equations. We show that careful analysis of these issues leads to strong constraints on the parameter space of the considered models. This, in turn, has important implications for phenomenology, as we show using examples of the double Higgs boson production, electroweak precision observables, and the electroweak phase transition.

Numerous exotic hadrons with heavy quarks have been reported in the experiments. In such states, symmetries of heavy quarks are considered to play a significant role. In particular, the superflavor symmetry, or also called the heavy quark antidiquark symmetry is one of the interesting symmetries, which links a quark $Q$ to an antidiquark $\overline{Q}\overline{Q}$ having the same color representation as $Q$. In this paper, we study a $\overline{D}{\mathrm{\Xi }}_{cc}$ molecular state as a superflavor partner of the doubly charmed tetraquark $T_{cc}$ reported by LHCb recently. $T_{cc}$ locating slightly below the $D{D}^{*}$ threshold is a candidate of the hadronic molecule. Thus by replacing the singly charmed meson $D^{(*)}$ with the doubly charmed baryon ${\mathrm{\Xi }}_{cc}^{(*)}$, superflavor symmetry predicts the existence of the ${\overline{D}}^{(*)}{\mathrm{\Xi }}_{cc}^{(*)}$ bound state. We employ the one boson exchange model respecting with the heavy quark spin symmetry where the parameter is obtained to reproduce the $T_{cc}$ binding energy. We apply this model with superflavor symmetry to the ${\overline{D}}^{(*)}{\mathrm{\Xi }}_{cc}^{(*)}$ molecule and predict a bound state with $I(J^P)=0({\frac{1}{2}}^{-})$. If the pentaquark state corresponding to ${\overline{D}}^{(*)}{\mathrm{\Xi }}_{cc}^{(*)}$ molecular state is observed in future experiments as predicted in this work, it is more likely that $T_{cc}$ is a $D{D}^{*}$ molecular state.

Quark spin effects in $e^{+}{e}^{-}$ annihilation to pseudoscalar and vector mesons are implemented for the first time in the pythia Monte Carlo event generator. The spin-dependent fragmentation of the string stretched between the produced quark-antiquark pair with correlated spin states is described by the $\mathrm{string}+{{}^{3}P}_0$ model implemented in the string fragmentation routine of pythia by using the StringSpinner package. The simulated events are used to study the model predictions for the Collins asymmetries of mesons produced back-to-back in the $e^{+}{e}^{-}$ center of mass system by using both the thrust axis method and the hadronic plane method. The obtained asymmetries are compared to the available data from the BELLE and BABAR experiments and the underlying Collins analyzing power from the $\mathrm{string}+{{}^{3}P}_0$ model is compared with phenomenological extractions.