We study fixed points of scalar fields that transform in the bifundamental representation of $O(N)\times O(M)$ in $3-\epsilon$ dimensions, generalizing the classic tricritical sextic vector model. In the limit where $N$ is large but $M$ is finite, we determine the complete beta function to order $1/N$ for arbitrary $M$. We find a rich collection of large-$N$ fixed points in $d=3$, as well as fixed points in $d=3-\epsilon$, that can be studied to all orders in the parameter $\widehat{\epsilon }=N\epsilon$. With the goal of defining a large-$N$ nonsupersymmetric conformal field theory dominated by a web of planar diagrams, we also study fixed points in the “bifundamental” large-$N$ limit, in which $M$ and $N$ are both large but the ratio $M/N$ is held fixed. We find a unique infrared fixed point in $d=3-\epsilon$, which we determine to order ${\epsilon }^2$. When $M/N\ll 1$, we also find an ultraviolet fixed point in $d=3$ and $d=3-\epsilon$ that merges with the infrared fixed point at $\epsilon \sim O(M/N)$. We expect at least one of two candidate fixed points in integer dimensions—the infrared fixed point in $d=2$ and the ultraviolet fixed point in $d=3$—to survive for finite values of $M/N$.

In a seminal paper, Unruh and Wald showed that the detection of a Rindler particle by a linearly uniformly accelerated detector coupled to a Klein-Gordon field in the Minkowski vacuum corresponds to the creation of a Minkowski particle from the inertial viewpoint. In this paper, we revisit the situation studied in that work, but now consider, addition what happens once the detector has been excited somewhere along its world line. From an orthodox point of view, the change in the state of field induced by the measurement is nonlocal and affects both in the left and right Rindler wedges. If one relies on a semiclassical treatment of gravity and takes it to be applicable to this context, this situation seems to open the possibility for designing superluminal communication protocols between two spacelike separated observers confined respectively to the right and left Rindler wedges respectively. We discuss the possible ways in which physics could prevent such measurement-induced, faster-than-light signaling protocols.

We take into account the subcritical case for dielectric media by exploiting an approximation allowing us to perform perturbative analytical calculations and still not implying low dispersive effects. We show that in the background of a specific solitonlike solution, pair-creation occurs and can display a thermal behavior governed by an effective temperature. The robustness of the approach is also corroborated by the analysis of the $\varphi \psi$-model related to the standard Hopfield model, for which analogous results are obtained.

I give a simple proof of the physical process first law of black hole thermodynamics including charged black holes, in which all perturbations are computed on the horizon.

As a vector-tensor theory including nonminimal coupling between the Ricci tensor and a vector field, the bumblebee gravity is a potential theory to test Lorentz symmetry violation. Recently, a new class of numerical spherical black holes in the bumblebee theory was constructed. In this paper, we investigate the associated local thermodynamic properties. By introducing a pair of conjugated thermodynamic quantities $X$ and $Y$, which can be interpreted as an extension of electric potential and charge of the Reissner-Nordström black holes, we numerically construct a new first law of thermodynamics for bumblebee black holes. We then study the constant-$Y$ processes in the entropy-charge parameter space. For the constant-$Y$ processes, we also calculate the heat capacity to study the local thermodynamic stability of the bumblebee black holes. For a negative nonminimal coupling coefficient $\xi$, we find both divergent and smooth phase transitions. For a positive but small $\xi$, only a divergent phase transition is found. It turns out that there is a critical value $0.4\kappa <{\xi }_c<0.5\kappa$ such that when ${\xi }_c<\xi <2\kappa$, even the divergent phase transition disappears and the bumblebee black holes thus become locally thermodynamically unstable regardless of the bumblebee charge. As for $\xi >2\kappa$, the smooth phase transition arises again but there no longer exists any discontinuous phase transition for the bumblebee black holes.

We investigate the scalar mode quadrupole radiation of gravitational waves in $F(R)$ modified gravity. In $F(R)$ gravity a massive scalar mode appears in the gravitational waves. We find explicit expressions for the quadrupole radiation and the energy current of the scalar mode in general $F(R)$ gravity models. We consider a binary star and a bouncing star as astronomical sources of the gravitational waves and calculate the quadrupole radiation of the scalar and tensor modes. The scalar mode radiates under spherically symmetric conditions, but the tensor modes do not. The scalar mode mass is estimated for some typical energy scales. We show a possibility to detect the scalar mode in the future gravitational waves observation.

Some binary black hole systems potentially observable in LISA could be in orbit around a supermassive black hole (SMBH). The imprint of relativistic three-body effects on the waveform of the binary can be used to estimate all the parameters of the triple system, in particular the mass of the SMBH. We determine the phase shift in the waveform due to the Doppler effect of the SMBH up to second order in velocity, which breaks a well-known exact degeneracy of the lowest-order Doppler effect between the mass of the SMBH and its inclination. We perform several parameter estimations for LISA signals including this additional dephasing in the wave, showing that one can determine accurately all the parameters of the three-body system. Our results indicate that one can measure the mass of a ${10}^8{M}_{\odot }$ SMBH with an accuracy better than $\sim 30\%$ (resp. $\sim 15\%$) by monitoring the waveform of a binary system whose period around the SMBH is less 100 yr (resp. 20 yr).

We discuss exact regular compact object solutions in higher-dimensional extensions of general relativity sourced by a phantom scalar field in arbitrary $D$ spacetime dimensions ($D>2$), for which a central singularity is absent. We follow a bottom-up approach, by means of which, by imposing the desired form of the solution to the metric function, we derive the form of the self-interaction scalar potential, which in general appears to depend on both the scalar-hair charge and the black-hole mass. We discuss in this context the validity of the first law of thermodynamics in such systems. Consistency requires the independence of the potential of the mass, imposing in this way the dependence of the mass on the scalar charge of a type that varies with the value of $D$, and according to the no-hair theorem dressing the regular black-hole solution with secondary hair. In $D=3$, 4 we demonstrate that the potential depends on the ratio of the scalar charge over the mass, and thus considered as a parameter of the theory. This feature, however, does not characterize higher-dimensional cases. Calculating the $D$-dimensional Kretschmann scalar we show that it is finite at the center point $r=0$ for arbitrary $D$, rendering the solutions regular. The phantom matter content of the theory is also regular at $r=0$; hence, the radial coordinate of our manifold is defined for $r\ge 0$. We explicitly discuss the cases of $D=3$, 4, 5, 6, 10, and demonstrate that we can have regular, asymptotically flat, black holes with secondary scalar hair.

A key feature of ultralight dark matter composed by bosons is the formation of superfluid Bose-Einstein condensate (BEC) structures on galactic scales. We study collisions of BEC solitonic and vortex structures in the framework of the Gross-Pitaevskii-Poisson model. It is found that the superfluid nature of bosonic dark matter leads to the formation of quantized vortex lines and vortex rings in interference patterns formed during collisions. Calculating the gravitational wave luminosity, we demonstrate that quantum interference patterns affect notably gravitational wave radiation. We reveal that superfluid self-gravitating BECs can form stable localized vortex structures which remain robust even after a head-on collision.

The forest of Lyman-$\alpha$ absorption lines detected in the spectra of distant quasars encodes information on the nature and properties of dark matter and the thermodynamics of diffuse baryonic material. Its main observable—the 1D flux power spectrum (FPS)—should exhibit a suppression on small scales and an enhancement on large scales in warm dark matter (WDM) cosmologies compared to standard $\mathrm{\Lambda }\mathrm{CDM}$. Here, we present an unprecedented suite of 1080 high-resolution cosmological hydrodynamical simulations run with the graphics processing unit-accelerated code cholla to study the evolution of the Lyman-$\alpha$ forest under a wide range of physically motivated gas thermal histories along with different free-streaming lengths of WDM thermal relics in the early Universe. A statistical comparison of synthetic data with the forest FPS measured down to the smallest velocity scales ever probed at redshifts $4.0\lesssim z\lesssim 5.2$ [E. Boera et al., Revealing reionization with the thermal history of the intergalactic medium: New constraints from the $\mathrm{Ly}\alpha$ flux power spectrum, Astrophys. J. 872, 101 (2019)] yields a lower-limit $m_{\mathrm{WDM}}>3.1\mathrm{keV}$ (95% C.L.) for the WDM particle mass and constrains the amplitude and spectrum of the photoheating and photoionizing background produced by star-forming galaxies and active galactic nuclei at these redshifts. Interestingly, our Bayesian inference analysis appears to weakly favor WDM models with a peak likelihood value at the thermal relic mass of $m_{\mathrm{WDM}}=4.5\mathrm{keV}$. We find that the suppression of the FPS from free-streaming saturates at $k\gtrsim 0.1\mathrm{s}{\mathrm{km}}^{-1}$ because of peculiar velocity smearing, and this saturated suppression combined with a slightly lower gas temperature provides a moderately better fit to the observed small-scale FPS for WDM cosmologies.

We study the nonperturbative evolution of inflationary fluctuations during preheating using fully nonlinear general-relativistic field-theory simulations. We choose a single-field inflationary model that is consistent with observational constraints and start the simulations at the end of inflation with fluctuations both in the field and its conjugate momentum. Gravity enhances the growth of density perturbations, which then collapse and virialize, forming long-lived stable oscillon-like stars that reach compactnesses $\mathcal{C}\equiv GM/R\sim {10}^{-3}–{10}^{-2}$. We find that $\mathcal{C}$ increases for larger field models, until it peaks due to the interplay between the overdensity growth and Hubble expansion rates. While gravitational effects can play an important role in the formation of compact oscillons during preheating, the objects are unlikely to collapse into primordial black holes without an additional enhancement of the initial inflationary fluctuations.

A $Z^{\prime }$ boson associated with a broken $U{(1)}_{L_{\mu }-L_{\tau }}$ gauge symmetry offers an economical solution to the long-standing $g_{\mu }-2$ anomaly, confirmed and strengthened by recent measurements at Fermilab. Here, we revisit the impact of such a $Z^{\prime }$ on the spectrum of high-energy astrophysical neutrinos, as measured by the IceCube experiment. This spectrum has been observed to exhibit a diplike feature at $E_{\nu }\sim 0.2–1\mathrm{PeV}$, which could plausibly arise from the physics of the sources themselves, but could also be the consequence of high-energy neutrinos resonantly scattering with the cosmic neutrino background, mediated by a $Z^{\prime }$ with a mass on the order of $m_{Z^{\prime }}\sim 10\mathrm{MeV}$. In this study, we calculate the impact of such a $Z^{\prime }$ on the high-energy neutrino spectrum for a variety of model parameters and source distributions. For couplings that can resolve the $g_{\mu }-2$ anomaly, we find that this model could self-consistently produce a spectral feature in better accordance with IceCube’s measurement, in particular if the neutrinos observed by IceCube predominantly originate from high-redshift sources. We comment on some theoretical ingredients whose knowledge will be sharpened in the coming years and that should contribute to a more robust characterization and possible detection of the feature.

Fast neutrino flavor conversions (FFCs) and collisional flavor instabilities (CFIs) potentially affect the dynamics of core-collapse supernovae and binary neutron star mergers. Under the assumption of homogeneous neutrinos, we investigate effects of neutrino emission and absorption (EA) by matter through both single and multienergy numerical simulations with a physically motivated setup. In our models, FFCs dominate over CFIs in the early phase, while EA secularly and significantly have impact on flavor conversions. They facilitate angular swaps or the full exchange between electron neutrinos (${\nu }_e$) and heavy-leptonic neutrinos (${\nu }_x$). As a result, the number density of ${\nu }_x$ becomes more abundant than the case without EA, despite the fact that the isotropization by EA terminates the FFCs earlier. In the later phase, the system approaches new asymptotic states characterized by EA and CFIs, in which rich energy-dependent structures also emerge. Multienergy effects sustain FFCs and the time evolution of the flavor conversion becomes energy dependent, which are essentially in line with effects of the isoenergetic scattering that we have studied previously. We also find that ${\nu }_x$ in the high-energy region convert into ${\nu }_e$ via flavor conversions and then they are absorbed through charged-current reactions, exhibiting the possibility of new path of heating matter.

The gravitational lensing effect at higher order under weak-field approximation is believed to be important to distinguish black holes and other compact objects such as wormholes. The deflection angle of a generic wormhole is difficult to solve analytically; thus approximation methods are implemented. In this paper, we investigate the weak-field deflection angle of a specific wormhole, the Ellis-Bronnikov wormhole, up to the $1/b^4$ order. We use different approximation formalisms, study their precision at $1/b^4$ order by a comparison to a purely numerical result, and finally rank these formalisms by their accuracy. Moreover, we find that certain formalisms are sensitive to the choice of coordinate system; thus it is important to choose the coordinate system appropriately for the evaluating of lensing physics.

The goal of this paper is to introduce a novel likelihood-based inferential framework for axion haloscopes that is valid under the commonly applied “rescanning” protocol. The proposed method enjoys short data acquisition times and simple tuning of the detector configuration. Local statistical significance and power are computed analytically, avoiding the need for burdensome simulations. Adequate corrections for the look-elsewhere effect are also discussed. The performance of our inferential strategy is compared with that of a simple method that exploits the geometric probability of rescan. Finally, we exemplify the method with an application to a HAYSTAC-type axion haloscope.

The newly observed gamma ray burst GRB221009A exhibits the existence of 10 TeV-scale photons, and the axion-photon conversion has been suggested as a candidate to explain such energetic features of GRB221009A. In this work we adopt a model to calculate the conversion probability of the energetic photons from GRB221009A to the Earth. The result shows that the penetration probability of photons with energy above ${10}^1\mathrm{TeV}$ can be up to ${10}^{-2}$ to ${10}^{-4}$ depending on the coupling constant $g_{a\gamma }$ and the axion mass $m_a$, together on the magnetic field parameters of the source galaxy of GRB221009A. We show that the parameters of the source galaxy, with the magnetic field handled by a cellular model, contribute a lot of uncertainties to the penetration probability, so we have more freedom to reconcile a variety of axionlike particle parameters from other observations with the Large High Altitude Air Shower Observatory observation. By comparing the results in this article with the data from Large High Altitude Air Shower Observatory, we can obtain more precise constraints on the ranges of these parameters.

The current design of space-based gravitational wave detectors utilizes heterodyne laser interferometry in intersatellite science measurements. Frequency variations of the heterodyne beat notes are predominantly caused by the Doppler effect from relative satellite motion along lines of sight. Generally considered to be outside the measurement band, this Doppler frequency shift appears to have been overlooked in numerical simulations of time-delay interferometry (TDI). However, the potential impact on the implementation of TDI should be assessed. The issue is particularly relevant to TianQin that features geocentric orbits, because of strong gravity disturbances from the Earth-Moon system at frequencies $<1\times {10}^{-4}\mathrm{Hz}$. In this proof-of-principle study, based on high-precision orbital data obtained from detailed gravity field modeling, we incorporate the Doppler shift in the generation of TianQin’s beat note phase signals. To remove the large-scale Doppler phase drift at frequencies $<1\times {10}^{-4}\mathrm{Hz}$, we develop a high-performance high-pass filter and consider two possible processing sequences, i.e., applying the filter before or after TDI combinations. Our simulation results favor the former and demonstrate successful removal of the low-frequency gravity disturbances for TianQin without degrading the TDI performance, assuming 10 m pseudo-ranging uncertainty. The filtering scheme can be used in developing the initial noise-reduction pipeline for TianQin.

From quantum field theory, we derive the chiral kinetic theory involving nonlinear quantum corrections coupled with spacetime-dependent electromagnetic fields and fluid velocity gradients. An equilibrium Wigner function determined by the kinetic equation verifies the nondissipativeness of the charge induced by the magneto-vortical coupling. We reveal that this nonlinear chiral kinetic theory is consistent with the one-loop Euler–Heisenberg effective theory, indicating an indirect evidence of the trace anomaly in the kinetic theory. We also argue a potential issue on the regularization, and demonstrate the availability of the point-splitting regularization in the nonlinear chiral kinetic theory.

In $U(1{)}_R$ extensions of supersymmetric models, the bino and its Dirac partner, the singlino, can play the role of right-handed neutrinos. The bino and the singlino form a pseudodirac pair, dubbed the “$\mathrm{bi}\nu \mathrm{o}$,” which can generate Standard Model neutrino masses via the inverse seesaw mechanism. We investigate the prospects for detecting long-lived $\mathrm{bi}\nu \mathrm{os}$ at SHiP, where GeV scale $\mathrm{bi}\nu \mathrm{os}$ can be copiously produced in the decays of mesons. We show that SHiP can probe new regions of parameter space that are complementary to searches for the lepton flavor-violating decay $\mu \to e\gamma$. This scenario provides a well-motivated benchmark for future experiments of a right-handed neutrino that mixes with all Standard Model neutrinos and is directly related to the generation of neutrino masses.