In the context of Hawking-like radiation in sonic black holes formed by Bose-Einstein condensates we investigate the modifications of the emission spectrum caused by a finite width of the sonic transition region connecting the subsonic to supersonic flow.

We explore a centaur geometry in Jackiw-Teitelboim gravity, which is an asymptotically anti–de Sitter (AdS) spacetime but in the IR admits a de Sitter (dS) bubble, with another AdS geometry in the deep IR. Thus, this geometry admits a holographic dual in the sense that it is asymptotically AdS. In an attempt to understand this geometry, we calculate the density of states of the putative boundary dual for such mixed geometries by evaluating the on-shell action. We compute the density of states analytically in the classical limit. The resultant density of states suggests that the degrees of freedom in the IR are reduced in such a putative boundary theory due to the IR modification corresponding to the dS bubble.

We consider an experimentalist, Alice, who creates a quantum superposition of a charged or massive body outside of a black hole (or, more generally, in the presence of a Killing horizon). It was previously shown that emission of soft photons/gravitons into the black hole will result in the decoherence of the components of the superposition if it is held open for a sufficiently long span of time. However, at any finite time, $t_c$, during the process, it is not obvious how much decoherence has irrevocably occurred. Equivalently, it is not obvious how much information an observer inside the black hole can extract about Alice’s superposition prior to time $t_c$. In this paper, we solve for the optimal experimental protocol to be followed by Alice for $t>t_c$ so as to minimize the decoherence of the components of her superposition. More precisely, given the entangling radiation that has passed through the horizon prior to the cross-section $\mathcal{C}$ corresponding to the time $t=t_c$ in Alice’s lab, we determine the “optimal purification” of this radiation beyond $\mathcal{C}$ such that the global quantum state of the radiation through the horizon has maximal overlap (quantum fidelity) with the Hartle-Hawking or Unruh vacuum. Due to the intricate low frequency entanglement structure of the quantum field theory vacuum state, we find this optimal purification to be nontrivial. In particular, even if Alice has already “closed” her superposition by bringing the components back together, we find that she can decrease the net decoherence of the components of her superposition somewhat by reopening it and performing further manipulations.

Supersymmetry based hybrid inflation models (called spontaneously broken supersymmetry by the Planck collaboration) are attractive for a number of reasons including the nice feature that inflation is associated with a local gauge symmetry breaking in the early universe. Models based on a minimal superpotential and a canonical Kähler potential have the important property that there is no eta problem and the supergravity corrections are adequately suppressed. Following Planck’s notation, the inflationary potential with sub-Planckian inflaton field values is approximately given by $V\simeq {\mathrm{\Lambda }}^4[1+{\alpha }_h\log (\varphi /M_{\mathrm{Pl}})]-m_{3/2}{\mathrm{\Lambda }}^2\varphi +{\mathrm{\Lambda }}^{4}O(\varphi /M_{\mathrm{Pl}}{)}^4$. Here $\mathrm{\Lambda }=\sqrt{\kappa }M$ denotes the energy scale of inflation, $M$ is the gauge symmetry breaking scale, $\kappa$ is a dimensionless parameter which fixes the inflaton mass ($\sqrt{2}\kappa M$), ${\alpha }_h$ is determined from quantum corrections in terms of $\kappa$ and the underlying gauge group, and the soft supersymmetry breaking term proportional to the gravitino mass $m_{3/2}$ ($\sim 10\mathrm{TeV}$) and linear in the inflaton field $\varphi$ is present during inflation. The final term in $V$ represents the leading supergravity correction which is well suppressed since $\varphi \lesssim M_{pl}$ [Note that the last two terms were not taken into account in the Planck analysis.] We provide estimates for the parameters $\kappa$ (and ${\alpha }_h$) that yield a scalar spectral index $n_s$ in the 0.96–0.98 range, which is fully consistent with the recent P-ACT-LB measurements presented by the Atacama Cosmology Telescope (as well as earlier measurements by Planck.) The gauge symmetry breaking scale $M$ is determined to be on the order of ${10}^{15}\mathrm{GeV}$ or so. We recall that In the absence of the soft SUSY breaking term proportional to $m_{3/2}$ in $V$, the spectral index $n_s\simeq 1-1/N=0.98$, where $N=50$ denotes the number of e-foldings. The tensor-to-scalar ratio $r$ in this minimal model is tiny, but it can reach values in the observable range, $r\lesssim 0.01$, in nonminimal models.

The trace anomaly $\mathrm{\Delta }\equiv 1/3-P/ϵ=1/3-\varphi$ quantifies the possibly broken conformal symmetry in supradense matter under pressure $P$ at energy density $ϵ$. Perturbative QCD (pQCD) predicts a vanishing $\mathrm{\Delta }$ at extremely high energy or baryon densities when the conformal symmetry is realized but its behavior at intermediate densities reachable in neutron stars (NSs) is still very uncertain. The extraction of $\mathrm{\Delta }$ from NS observations strongly depends on the employed model for nuclear equation of state (EOS). Using the IPAD-TOV method based on an intrinsic and perturbative analysis of the dimensionless (IPAD) Tolman-Oppenheimer-Volkoff (TOV) equations that are further verified numerically by using ${10}^5$ EOSs generated randomly with a metamodel in a very broad EOS parameter space constrained by terrestrial nuclear experiments and astrophysical observations, here we first show that the compactness $\xi \equiv G{M}_{\mathrm{NS}}/R{c}^2\equiv M_{\mathrm{NS}}/R$ of a NS with mass $M_{\mathrm{NS}}$ and radius $R$ scales very accurately with ${\overline{\mathrm{\Pi }}}_{\mathrm{c}}\equiv {\mathrm{\Pi }}_{\mathrm{c}}·(1+18\mathrm{X}/25)\equiv \mathrm{X}/(1+3{\mathrm{X}}^2+4\mathrm{X})·(1+18\mathrm{X}/25)$ where $\mathrm{X}\equiv {\varphi }_{\mathrm{c}}=P_{\mathrm{c}}/{ϵ}_{\mathrm{c}}$ is the ratio of pressure over energy density at NS centers. The scaling of NS compactness thus enables one to readily read off the central trace anomaly ${\mathrm{\Delta }}_{\mathrm{c}}=1/3-\mathrm{X}$ directly from the observational data of either the mass-radius or red-shift measurements. We then demonstrate indeed that the available NS data themselves from recent X-ray and gravitational wave observations can determine model insensitively the trace anomaly as a function of energy density in NS cores, providing a stringent test of existing NS models and a clear guidance in a new direction for further understanding the nature and EOS of supradense matter.

The effective mass and decay width of the $\varphi$ meson in the isospin asymmetric hot and dense resonance matter are studied using the effective Lagrangian framework considering the $\varphi K\overline{K}$ interactions at one-loop level. In addition to spin-$1/2$ octet baryons, we consider the effect of resonances ${\mathrm{\Delta }}^{++,+,0,-},{\mathrm{\Sigma }}^{*\pm ,0},{\mathrm{\Xi }}^{*0,-},{\mathrm{\Omega }}^{-}$, on the properties of $\varphi$ meson. The in-medium effects on the $\varphi$ meson properties are simulated through the effective masses of kaons and antikaons computed using the chiral SU(3) hadronic mean field model in the presence of resonance baryons. The loop integral appearing in the computation of $\varphi$ meson self-energies is regularized using the dipole form factor with a cutoff parameter. The presence of resonance baryons within the medium at finite temperature is observed to significantly modify the effective mass and decay width of $\varphi$ mesons. Examining the $\varphi$ meson masses and decay width within a dense medium is anticipated to be essential for understanding experimental results from heavy-ion collision experiments.

We establish the correspondence between two well-known frameworks for quantum chromodynamics (QCD) multiple scattering in nuclear media: the color glass condensate (CGC) and the high-twist (HT) expansion formalism. We argue that a consistent matching between both frameworks, in their common domain of validity, is achieved by incorporating the subeikonal longitudinal momentum phase in the CGC formalism, which mediates the transition between coherent and incoherent scattering. We perform a detailed calculation and analysis of direct photon production in proton-nucleus scattering as a concrete example to establish the matching between HT and CGC up to twist-4, including initial- and final-state interactions, as well as their interferences. The techniques developed in this work can be adapted to other processes in electron-nucleus and proton-nucleus collisions, and they provide a potential avenue for a unified picture of dilute-dense dynamics in nuclear media.

The utility of the non-relativistic large-charge effective field theory (EFT) for physical systems, and neutron matter, in particular, relies on controlled Schrödinger-symmetry breaking deformations due to scattering length and effective-range effects in the two-body system. A recently found exact solution of the large-charge system is used to compute these effects for two-point correlation functions of large-charge operators in perturbation theory around the large-charge ground state. Notably, the leading effective-range effects are found to enter at second order in the effective range, in agreement with analogous calculations in the three-body system. The Schrödinger-symmetry breaking deformations are used—together with input from quantum Monte Carlo simulation—to address the range of validity of the EFT with deformations both in general and in the special case of neutron matter. In particular, it is found that nuclear reactions with up to six low-energy neutrons in the final state can be described by the large-charge EFT with Schrödinger-symmetry breaking.

A first determination of the strong-phase difference between $D^0$ and $\overline{D^0}\to K^{+}{K}^{-}{\pi }^{+}{\pi }^{-}$ is performed using $e^{+}{e}^{-}\to \psi (3770)\to D\overline{D}$ data collected by the BESIII detector corresponding to an integrated luminosity of $20.3{\mathrm{fb}}^{-1}$. The measurements are made in four pairs of bins in phase space, which are chosen to provide optimal sensitivity to the angle $\gamma$ of the unitarity triangle in $B^{\pm }\to D{K}^{\pm }$ decays. From these measurements, it follows that the $CP$-even fraction of the decay is $F_{+}=0.754\pm 0.010_{\mathrm{stat}}\pm 0.008_{\mathrm{syst}}$. In addition, the branching fraction of $D^0\to K^{+}{K}^{-}{\pi }^{+}{\pi }^{-}$ is measured to be $(2.863\pm 0.028_{\mathrm{stat}}\pm 0.045_{\mathrm{syst}})\times {10}^{-3}$, which is twice as precise as previous results obtained at other experiments.

The soft photon and soft graviton theorems of Weinberg are known to derive from conservation laws associated with asymptotic symmetries. Within the corresponding classical theories, one often speaks of spontaneous symmetry breaking and vacuum degeneracy, but a genuine quantum description of this phenomenon has largely been lacking. Here we establish spontaneous symmetry breaking of asymptotic symmetries and the existence of Goldstone particles using exclusively the language of quantum field theory. This is made possible through the reformulation of massless scattering theory in terms of Carrollian conformal field theory, and the observation that soft theorems correspond to Ward identities of broken symmetries. A suitable version of Goldstone theorem shows that there must exist zero-momentum particles described by conformal fields on the celestial sphere, in agreement with the common lore. More specifically, these belong to unitary representations in the discrete series of the Lorentz group, and are therefore naturally equipped with logarithmic two-point functions. We discuss the relevance of these observations to the problem of infrared divergences that scattering amplitudes suffer from.

In AdS/CFT holography, two manifestations of the black hole information paradox are given by the nonisometric nature of the bulk-boundary map and by the factorisation puzzle. By considering time-shifted microstates of the eternal black hole, we demonstrate that both puzzles may be simultaneously resolved by taking into account nonlocal quantum corrections that correspond to wormholes arising from state averaging. This is achieved by showing, using a resolvent technique, that the resulting Hilbert space for an eternal black hole is finite-dimensional with a discrete energy spectrum. The latter gives rise to a transition to a type I von Neumann algebra.

Consider at a finite temperature $T$ a superfluid moving with a velocity $v$ relative to the thermal bath or its normal component. From Landau’s argument there exists a critical $v_c(T)$ beyond which excitations can be spontaneously generated, and the system becomes unstable. Identifying the final state induced by such an instability has been an outstanding open question. Using holographic duality we perform dynamical simulations of evolutions from initial unstable states, and find that the system settles to a homogenous superfluid state with a final velocity below the critical velocity. The dynamical evolution process appears to be highly chaotic, exhibiting transient turbulence. Nevertheless we are able to identify from the simulations a universal physical mechanism for the reduction of superfluid velocity, in terms of the spontaneous nucleation of solitons. We also derive a simple analytic formula which relates the final velocity to the number of solitons nucleated during the evolution.

We perform a thorough investigation of the universality of the long-distance matrix elements (LDMEs) of nonrelativistic QCD factorization based on a next-to-leading order (NLO) fit of $J/\psi$ color octet LDMEs to high transverse momentum $p_T$ $J/\psi$ and ${\eta }_c$ production data at the LHC. We thereby apply a novel fit-and-predict procedure to systematically take into account scale variations, and predict various observables never studied in this context before. In particular, the LDMEs can well describe $J/\psi$ hadroproduction up to the highest measured values of $p_T$, as well as $\mathrm{\Upsilon }(nS)$ production via potential nonrelativistic QCD based relations. Furthermore, $J/\psi$ production in $\gamma \gamma$ and $\gamma p$ collisions is surprisingly reproduced down to $p_T=1\mathrm{GeV}$, as long as the region of large inelasticity $z$ is excluded, which may be of significance in future quarkonium studies, in particular at the EIC and the high-luminosity LHC. In addition, our summary reveals an interesting pattern as to which observables still evade a consistent description.

We present a Bayesian holographic model constructed by integrating the equation of state and baryon number susceptibility at zero chemical potential from lattice quantum chromodynamics (QCD). The model incorporates error estimates derived from lattice data. With this model, we systematically investigate the thermodynamic properties of the $2+1$-flavor QCD system. Using Bayesian inference, we perform precise calibration of the model parameters and determined the critical end point (CEP) position under the maximum a posterior (MAP) estimation to be $(T^c,{\mu }_B^c)=(0.0859\mathrm{GeV},0.742\mathrm{GeV})$. Additionally, we predict the CEP positions within 68% and 95% confidence levels, yielding $(T^c,{\mu }_B^c{)}_{68\%}=(0.0820-0.0889,0.71-0.77)\mathrm{GeV}$ and $(T^c,{\mu }_B^c{)}_{95\%}=(0.0816-0.0898,0.71-0.79)\mathrm{GeV}$, respectively. Moreover, to validate the reliability and predictive power of our approach, we conduct a comprehensive comparison between our predictions and potential CEP locations proposed by other theoretical models. This work not only establishes a novel Bayesian framework for holographic modeling but also provides valuable insights and theoretical support for exploring phase transitions in strongly interacting matter under extreme conditions.

The recent increase in computational resources and data availability has led to a significant rise in the use of machine learning (ML) techniques for data analysis in physics. However, the application of ML methods to solve differential equations capable of describing even complex physical systems is not yet fully widespread in theoretical high-energy physics. Hamiltonian neural networks (HNNs) are tools that minimize a loss function defined to solve Hamilton equations of motion. In this work, we implement several HNNs trained to solve, with high accuracy, the Hamilton equations for a massless probe moving inside a smooth and horizonless geometry known as a D1-D5 circular fuzzball. We study both planar (equatorial) and nonplanar geodesics in different regimes according to the impact parameter, some of which are unstable. Our findings suggest that HNNs could eventually replace standard numerical integrators, as they are equally accurate but more reliable in critical situations.

Verlinde and Zurek (VZ) have proposed that quantum gravity fluctuations in causal diamonds lead to observable effects. In particular, they argued that in quantum gravity causal diamonds have an uncertainty in their size that scales as $\delta L\sim \sqrt{{\ell }_{p}L}$, i.e. fluctuations are enhanced from the Planck scale. In this work, we explore the origin of the VZ scaling by studying scalar perturbations in inflationary cosmology. We reinterpret these cosmological perturbations as fluctuations of the modular Hamiltonian associated with a causal diamond, establishing a connection between modular fluctuations and observable primordial perturbations. Independent of assumptions about the modular Hamiltonian or the background spacetime, our results show that—whenever an (effective) spherically symmetric perturbation is quantized—it can lead to the VZ scaling. However, whether such a mode exists in the vacuum of any theory of quantum gravity remains an open question.

A study of Rényi entanglement entropy in the Sachdev-Ye-Kitaev (SYK) chain of Majorana fermions suggested that the model does not rapidly thermalize, despite being maximally chaotic. In this work, I examine the eigenstate thermalization hypothesis (ETH) for both the SYK chain and the two-site SYK models using exact diagonalization. I focus on two physically motivated few-body observables: the one-body particle number operator and the two-body hopping operator. These operators provide insight into local occupation and, in certain contexts, may reflect aspects of transport. Both operators have been employed in previous studies of the ETH in related SYK models. I show that single realizations of both models approximately satisfy ETH conditions for these operators, while ensemble averages strictly satisfy the ETH. Therefore, I conclude that the finite-size SYK chain and two-site SYK models can rapidly thermalize with respect to these observables through the ETH mechanism. This suggests that the subthermal behavior observed in previous studies of Rényi entanglement entropy does not manifest in finite-size systems and that these systems can thermalize rapidly via their light modes. It also indicates that the proposed gravitational dual may undergo rapid thermalization.

We introduce a nonperturbative approach to calculate the Rényi entropy of a single interval on the torus for single-character (meromorphic) conformal field theories. Our prescription uses the Wrońskian method of Mathur, Mukhi, and Sen [Nucl. Phys. B312, 15 (1989)], in which we construct differential equations for torus conformal blocks of the twist two-point function. As an illustrative example, we provide a detailed calculation of the second Rényi entropy for the ${\mathrm{E}}_{8,1}$ Wess-Zumino-Witten (WZW) model. We find that the ${\mathbb{Z}}_2$ cyclic orbifold of a meromorphic conformal field theory (CFT) results in a four-character CFT, which realizes the toric code modular tensor category. The ${\mathbb{Z}}_2$ cyclic orbifold of the ${\mathrm{E}}_{8,1}$ WZW model, however, yields a three-character CFT since two of the characters coincide. We then compute the torus conformal blocks and find that the twist two-point function, and therefore the Rényi entropy, is two-periodic along each cycle of the torus. The second Rényi entropy for a single interval of the ${\mathrm{E}}_{8,1}$ WZW model has the universal logarithmic divergent behavior in the decompactification limit of the torus, as expected as well as the interval approaches the size of the cycle of the torus. Furthermore, we see that the $q$-expansion is UV finite, apart from the leading universal logarithmic divergence. We also find that there is a divergence as the size of the entangling interval approaches the cycle of the torus, suggesting that gluing two tori along an interval the size of a cycle is a singular limit.

Recently, subdimensional particles including fractons have attracted much attention from various areas. Notable features of such matter phases are mobility constraints and subextensive ground-state degeneracies (GSDs). In this paper, we propose a BF-like theory motivated by the Godbillon-Vey invariant, which is a mathematical invariant of the foliated manifold. Our theory hosts subsystem higher-form symmetries which manifestly ensure the mobility constraint and subextensive GSD through the spontaneous symmetry breaking. We also discuss some lattice spin models which realize the same low-energy behaviors as the BF-like theory. Furthermore, we explore dynamical matter theories which are coupled to the BF-like theory.

We apply the result of Kenneth and Klich [Phys. Rev. Lett. 97, 160401 (2006)] to derive a theorem for two objects coupled to a Dirac field. We demonstrate that a sufficient condition for the Casimir interaction to be repulsive is for their geometric configuration to be odd under the same reflection operation considered in that work.