In this work, we propose two possibilities of $CPT$-odd and Lorentz-violating (LV) nonminimal couplings in the electroweak sector. These terms are gauge-invariant and couple a fixed 4-vector to the physical fields of the theory. After determining the LV contributions to the electroweak currents, we reassess the evaluation of the decay rate for the vector mediators $W$ and $Z$. Using the experimental uncertainty in these decay rates, upper bounds of 1 part in ${10}^{-6}(\mathrm{GeV}{)}^{-1}$ and ${10}^{-5}(\mathrm{GeV}{)}^{-1}$ are imposed on the magnitude of the proposed nonmimal interactions.

We provide a mapping between past null and future null infinity in three-dimensional flat space, using symmetry considerations. From this we derive a mapping between the corresponding asymptotic symmetry groups. By studying the metric at asymptotic regions, we find that the mapping is energy preserving and yields an infinite number of conservation laws.

In this paper, using the holographic prescription, we study multispin bound states and their dispersion relations over the $\kappa$-deformed ${\mathrm{AdS}}_3\times S^3$ background. In the first part of our analysis, considering the conformal gauge conditions (associated with the Polyakov action) we explore the dispersion relation associated with spin-two bound states at strong coupling. We solve corresponding world-sheet fluctuations and compute all the conserved quantities associated with the stringy dynamics over the deformed background. In the second part of our analysis, we perform a similar analysis for spin-three configurations. In both cases, we observe the emergence of nontrivial background deformation that vanishes in the limit, $\kappa \to 0$.

In this work, we address the reconstruction problem, investigating the construction of field theories from supersymmetric quantum mechanics. The procedure is reviewed, starting from reflectionless potentials that admit one and two bound states. We show that, although the field theory reconstructed from the potential that supports a single bound state is unique, it may break unicity in the case of two bound states. We illustrate this with an example, which leads us to two distinct field theories.

We study the Casimir vacuum energy density and the Casimir pressure for a massless scalar field confined between two nearby parallel plates in a slightly curved, static spacetime background, employing the weak-field approximation in the framework of extended theories of gravity (ETG). Following a perturbative approach, we find the gravity corrections to the Casimir vacuum energy density and pressure. The corrections to the vacuum energy density in the framework of general relativity (GR) are small, and today they are still undetected with current technology. However, future sensitivity improvements in gravitational interferometer experiments will give a useful tool to detect such effects induced by gravity. For these reasons, which are interesting from a theoretical point of view, we generalize the outcomes of GR in the context of ETG. Finally, we find the general relation to constrain the free parameters of the ETG.

We present a new formulation for the canonical approach to conformal (Weyl-squared) gravity and its extension by the Einstein-Hilbert term and a nonminimally coupled scalar field. For this purpose we use a unimodular decomposition of the three-metric and introduce unimodular-conformal canonical variables. The important feature of this choice is that only the scale part of the three-metric and the rescaled trace part of the extrinsic curvature change under a conformal transformation. This significantly simplifies the constraint analysis and manifestly reveals the conformal properties of a theory that contains the conformally invariant Weyl-tensor term. The conformal symmetry breaking which occurs in the presence of the Einstein-Hilbert term and a nonconformally coupled scalar field can then be interpreted directly in terms of this scale and this trace. We also discuss in detail the generator for the conformal transformations. This new Hamiltonian formulation is especially suitable for quantization, which is the subject of a separate paper.

Employing a simplified version of the Israel-Stewart formalism for general-relativistic shear-viscous hydrodynamics, we perform axisymmetric general-relativistic simulations for a rotating neutron star surrounded by a massive torus, which can be formed from differentially rotating stars. We show that with our choice of a shear-viscous hydrodynamics formalism, the simulations can be stably performed for a long time scale. We also demonstrate that with a possibly high shear-viscous coefficient, not only viscous angular momentum transport works but also an outflow could be driven from a hot envelope around the neutron star for a time scale $\gtrsim 100\mathrm{ms}$ with the ejecta mass $\gtrsim {10}^{-2}{M}_{\odot }$, which is comparable to the typical mass for dynamical ejecta of binary neutron-star mergers. This suggests that massive neutron stars surrounded by a massive torus, which are typical outcomes formed after the merger of binary neutron stars, could be the dominant source for providing neutron-rich ejecta, if the effective shear viscosity is sufficiently high, i.e., if the viscous $\alpha$ parameter is $\gtrsim {10}^{-2}$. The present numerical result indicates the importance of a future high-resolution magnetohydrodynamics simulation that is the unique approach to clarify the viscous effect in the merger remnants of binary neutron stars by the first-principle manner.

To solve the $\mu$ problem of the MSSM, the $\mu$ from $\nu$ supersymmetric standard model ($\mu \nu \mathrm{SSM}$) introduces three singlet right-handed neutrino superfields ${\widehat{\nu }}_i^c$, which lead to the mixing of the neutral components of the Higgs doublets with the sneutrinos, producing a relatively large $CP$-even neutral scalar mass matrix. In this work, we analytically diagonalize the $CP$-even neutral scalar mass matrix and analyze in detail how the mixing impacts the lightest Higgs boson mass. We also give an approximate expression for the lightest Higgs boson mass. Simultaneously, we consider the radiative corrections to the Higgs boson masses with effective potential methods.

We study the decays $B\to D^{(*)}\tau {\nu }_{\tau }$ in light of the available data from BABAR, Belle, and LHCb. We divide our analysis into two parts: in one part we fit the form factors in these decays directly from the data without adding any additional new physics contributions and compare our fit results with those available from the decays $B\to D^{(*)}\ell {\nu }_{\ell }$. We find that the $q^2$ distributions of the form factors associated with the pseudovector current, obtained from $B\to D^{(*)}\tau {\nu }_{\tau }$ and $B\to D^{(*)}\ell {\nu }_{\ell }$ respectively, do not agree with each other, whereas the other form factors are consistent with each other. In the next part of our analysis, we look for possible new effective operators of dimension 6 amongst new vector, scalar, and tensor types that can best explain the current data in the decays $B\to D^{(*)}\tau {\nu }_{\tau }$. We use the information-theoretic approaches, especially of the “second-order Akaike information criterion” in the analysis of empirical data. Normality tests for the distribution of residuals are done after selecting the best possible scenarios, for cross validation. We find that it is the contribution from the operator involving left- or right-handed vector current that passes all the selection criteria defined for the best-fit scenario and that can successfully accommodate all the available data sets.

We consider the chiral separation effect (CSE) in the lattice-regularized quantum field theory. We discuss two types of regularization: with and without exact chiral symmetry. In the latter case this effect is described by its conventional expression for the massless fermions. This is illustrated by the two particular cases of Wilson fermions and the conventional overlap fermions. At the same time, in the presence of the exact chiral symmetry the CSE disappears. This is illustrated by the naive lattice fermions, when the contributions of the fermion doublers cancel each other. Another example is the modified version of the overlap regularization proposed recently, where there is exact chiral symmetry, but as a price for this the fermion doublers become zeros of the Green function. In this case the contributions to the CSE of zeros and poles of the Green function cancel each other.

We calculate the inclusive spectra of secondaries produced in soft (minimum-bias) pPb collisions in the framework of the quark-gluon string model at LHC energy, by taking into account the inelastic screening corrections (percolation effects). The role of these effects is expected to be very large at the very high energies, and they should decrease the spectra more than 2 times in the midrapidity region at ${\sqrt{s}}_{NN}=5\mathrm{TeV}$.

A ${}^{220}\mathrm{Rn}$ source is deployed on the XENON100 dark matter detector in order to address the challenges in calibration of tonne-scale liquid noble element detectors. We show that the ${}^{212}\mathrm{Pb}$ beta emission can be used for low-energy electronic recoil calibration in searches for dark matter. The isotope spreads throughout the entire active region of the detector, and its activity naturally decays below background level within a week after the source is closed. We find no increase in the activity of the troublesome ${}^{222}\mathrm{Rn}$ background after calibration. Alpha emitters are also distributed throughout the detector and facilitate calibration of its response to ${}^{222}\mathrm{Rn}$. Using the delayed coincidence of ${}^{220}\mathrm{Rn}\text{−}{}^{216}\mathrm{Po}$, we map for the first time the convective motion of particles in the XENON100 detector. Additionally, we make a competitive measurement of the half-life of ${}^{212}\mathrm{Po}$, $t_{1/2}=(293.9\pm (1.0{)}_{\mathrm{stat}}\pm (0.6{)}_{\mathrm{sys}})\mathrm{ns}$.

We use the compatibility of D-brane action with linear off-shell T-duality and linear on-shell S-duality as guiding principles to find all world-volume couplings of one massless closed and three massless open strings at order ${\alpha }^{\prime 2}$ in type II superstring theories in flat spacetime.

We develop an analytic perturbative expansion to study the propagation of entanglement entropy for small subsystems after a global quench, in the context of the $\mathrm{AdS}/\mathrm{CFT}$ correspondence. Opposite to the large interval limit, in this case the evolution of the system takes place at time scales that are shorter in comparison to the local equilibration scale and, thus, different physical mechanisms govern the dynamics and subsequent thermalization. In particular, we show that the heuristic picture in terms of an “entanglement tsunami” does not apply in this regime. We find two crucial differences: First, that the instantaneous rate of growth of the entanglement is not constrained by causality, but rather its time average and, second, that the approach to saturation is always continuous, regardless of the shape of the entangling surface. Our analytic expansion also enables us to verify some previous numerical results, namely, that the saturation time is nonmonotonic with respect to the chemical potential. All of our results are pertinent to CFTs with a classical gravity dual formulation.

A discrete quantum spin system is presented in which several modern methods of canonical quantum gravity can be tested with promising results. In particular, features of interacting dynamics are analyzed with an emphasis on homogeneous configurations and the dynamical building-up and stability of long-range correlations. Different types of homogeneous minisuperspace models are introduced for the system, including one based on condensate states, and shown to capture different aspects of the discrete system. They are evaluated with effective methods and by means of continuum limits, showing good agreement with operator calculations whenever the latter are available. As a possibly quite general result, it is concluded that an analysis of the building-up of long-range correlations in discrete systems requires nonperturbative solutions of the dynamical equations. Some questions related to stability can be analyzed perturbatively but suggest that matter couplings may be relevant for this question in the context of quantum cosmology.

Holographic models provide unique laboratories to investigate nonlinear physics of transport in inhomogeneous systems. We provide a detailed account of both dc and ac conductivities in a defect conformal field theory with spontaneous stripe order. The spatial symmetry is broken at large chemical potential, and the resulting ground state is a combination of a spin and charge density wave. An infinitesimal applied electric field across the stripes will cause the stripes to slide over the underlying density of smeared impurities, a phenomenon which can be associated with the Goldstone mode for the spontaneously broken translation symmetry. We show that the presence of a spatially modulated background magnetization current thwarts the expression of some dc conductivities in terms of horizon data.

We analyze the smooth and sharp creation of a pointlike source for a quantized massless scalar field in ($3+1$)-dimensional Minkowski spacetime, as a model for the breakdown of correlations that has been proposed to occur at the horizon of an evaporating black hole. The creation is implemented by a time-dependent self-adjointness parameter at the excised spatial origin. In a smooth creation, the renormalized energy density $⟨T_{00}⟩$ is well defined away from the source, but it is unbounded both above and below: the outgoing pulse contains an infinite negative energy, while a cloud of infinite positive energy lingers near the fully-formed source. In the sharp creation limit, $⟨T_{00}⟩$ diverges everywhere in the timelike future of the creation event, and so does the response of an Unruh-DeWitt detector that operates in the timelike future of the creation event. The source creation is significantly more singular than the corresponding process in $1+1$ dimensions, analyzed previously, and it may be sufficiently singular to break quantum correlations as proposed in a black hole spacetime.

We study correlation functions of magnetic vortices $V$ and Polyakov loop $P$ operators in the $(2+1)$-dimensional Georgi-Glashow model in the vicinity of the deconfining phase transition. In this regime, the (dimensionally reduced) model is mapped onto a free theory of two massive Majorana fermions. We utilize this fermionic representation to explicitly calculate the expectation values of $V$ and $P$ as well as their correlators. In particular, we show that the $VV$ correlator is large, and thus the anomalous breaking of the magnetic $U(1)$ symmetry is order 1 effect in the near critical region. We also calculate the contribution of magnetic vortices to the entropy and the free energy of the system.

We construct several exact solutions for a recently proposed geometric scalar theory of gravity. We focus on a class of axisymmetric geometries and a big-bang-like geometry and discuss their Lorentzian character. The axisymmetric solutions are parametrized by an integer angular momentum $l$. The $l=0$ (spherical) case gives rise to the Schwarzschild geometry. The other solutions have naked singular surfaces. While not a priori obvious, all the solutions that we present here are globally Lorentzian. The Lorentzian signature appears to be a robust property of the disformal geometries solving the vacuum geometric scalar theory of gravity equations.

We consider two consecutive Universes (eons) with positive cosmological constants within the framework of Penrose’s conformal cyclic cosmology. If we assume that both eons are filled with perfect fluids and that they both are conformal to the metric of Einstein’s static universe by an analytic conformal transformation, then, using the Eisntein field equations, we prove that a) the fluids can only belong to five classes (cosmological constant, radiation, dust, and two other classes with negative pressures corresponding to a gas of strings and a gas of domain walls), b) the field equations on both sides of the future/eternity hypersurface exhibit certain duality, and c) both eons (one at the end and the other at the beginning) are almost critical so that the future eon is dominated by radiation and resembles the beginning of our Universe.