International Journal of Modern Physics A

In this article we give an overview of the concept of universal dynamics near non-thermal fixed points in isolated quantum many-body systems. We outline a non-perturbative kinetic theory derived within a Schwinger–Keldysh closed-time path-integral approach, as well as a low-energy effective field theory which enable us to predict the universal scaling exponents characterizing the time evolution at the fixed point. We discuss the role of wave-turbulent transport in the context of such fixed points and discuss universal scaling evolution of systems bearing ensembles of (quasi) topological defects. This is rounded off by the recently introduced concept of prescaling as a generic feature of the evolution towards a non-thermal fixed point.

We describe work being done at Baylor University investigating the possibility of new states of mesonic matter containing two or more quark–antiquark pairs. To put things in context, we begin by describing the lattice approach to hadronic physics. We point out there is a need for a quark model which can give an overall view of the quark interaction landscape. A new application of the Thomas–Fermi (TF) statistical quark model is described, similar to a previous application to baryons. The main usefulness of this model will be to detect systematic energy trends in the composition of the various particles. It could be a key to identifying families of bound states, rather than individual cases. Numerical results based upon a set of parameters derived from a phenomenological model of tetraquarks are given.

We consider the possibility that the preons defined by the SLq(2) extension of the Standard Model may be identified with Schwinger dyons. The SLq(2) extension is here presented as a model that may exist in either a currently observable electric phase or in a magnetic phase that is predicted but currently unobservable.

The discovery of the $SU(3)$ symmetry was fundamental as to establishing an ordering principle in particle physics. We already studied how to couple the $SU(3)$ symmetry to the gravitational field in four-dimensional curved Lorentzian space–times. The multiplets of equal quantum numbers are translated through natural elements in Riemannian geometry into local multiplets of equal gravitational field. As quark physics developed since in the 1970s, it was necessary to incorporate new symmetries to the models, that ensued in the incorporation of new quantum numbers like charm, for example, charm is an additive quantum number like isospin $T_3$ and hypercharge $Y$ and the standard $T_3-Y$ diagrams were extended onto another third axis. Then, instead of the fundamental triplet, we have a quartet $\{u,d,s,c\}$ as the smallest representation of the symmetry group, leading to the introduction of $SU(4)$ as the new group of symmetries. In this paper, we will not restrict ourselves exclusively to the symmetry group $SU(4)$ and we will set out to analyze the coupling of the $SU(N)$ symmetry to the gravitational field. To this end, new tetrads will be introduced as we did for the $SU(3)\times SU(2)\times U(1)$ case. These tetrads have outstanding properties that enable these constructions. New theorems will be proved regarding the isomorphic nature of these local symmetry gauge groups and tensor products of groups of local tetrad transformations. This is a paper about grand field unification in four-dimensional curved Lorentzian space–times.

Potential discovery, observation and exclusion limits of excited $u$ and $d$ quarks with gamma$+$jet final state are researched at the multi-TeV scale colliders, FCC and S$pp$C in this paper. Both colliders, FCC and S$pp$C, show that excited $u$ and $d$ quarks could be discovered up to 42.1 TeV and 55.2 TeV for $u^{\star }$, 30.3 TeV and 39.4 TeV for $d^{\star }$ and 42.3 TeV and 55.5 TeV mass values for degenerate case $(m_{u^{\star }}=m_{d^{\star }})$, respectively. The determination of the excited quarks compositeness scale is examined, which will be up to multi-PeV level. Besides these analyses, free parameters ($f_s$, $f$ and $f^{\prime }$) are scanned from around 0.1 up to 1 that show excited quark could be discovered at dozens of TeV with even coupling constants under 0.1.

The magnetic-color-flavor-locked quark matter is investigated in the Nambu–Jona-Lasinio model. Strong nonuniform magnetic fields are employed in order to mimic the spatial dependence of the magnetic field strength at high densities. We find that the gap solution depends strongly on the diquark coupling interaction. Based on the requirement that the parallel pressure should be an increasing function of the chemical potential, an upper limit on the central magnetic field $3.58\times 10^{18}$G is obtained, which increases slightly with the diquark interaction strength. Furthermore, much stronger central magnetic field could occur in the stars composed of magnetic-color-flavor matter than that of ordinary strange quark matter.

Chiral edge states of $(2+1)$-dimensional Abelian and non-Abelian topological phases can be represented by chiral conformal field theories with integer and noninteger values of central charge, respectively. In this work we describe certain edge states in terms of constrained fermionic fields that realize chiral coset CFT structures. This construction arises naturally in the so-called quantum wires approach for topological phases and allows for representing fractionalized edge states directly in terms of fermionic degrees of freedom. At the same time, the constrained fermions description introduces some subtleties concerning gauge anomalies since it involves the coupling of chiral fermions to gauge fields. We describe in this paper how to handle these issues.

In hadron interactions at the LHC energies, the reflective scattering mode starts to play a noticeable role which is expected to be even a more significant beyond the energies of the LHC. This new but still arguable phenomenon implies a peripheral dependence of the inelastic probability distribution in the impact parameter space and asymptotically evolving to the black ring. As a consequence, the straightforward extension to hadrons of the centrality definition adopted for nuclei needs to be modified.

We study the spectral function of the axial-vector charmonium state ${\chi }_{c1}(2P)$ coupled to $D{D}^{\ast }$ mesons, by employing a quantum field theoretical approach: a pronounced enhancement close to the $D^0{D}^{\ast 0}$ threshold, to be identified with the $X(3872)$, emerges. In the complex plane we find two poles: a pole for the broad seed state ${\chi }_{c1}(2P)$, and — in the easiest scenario — a virtual pole for the $X(3872)$. Thus, our approach describes both the seed state and the dynamically generated $X(3872)$ simultaneously. In particular, it explains the most prominent, both molecular-like and quarkonium-like, features of the $X(3872)$: its very small width (the decay into $D^0{D}^{\ast 0}$ is predicted to be about 0.5 MeV), the enhanced radiative decay into $\psi (2S)\gamma$ with respect to $\psi (1S)\gamma$, and the isospin breaking decay into $J/\psi \rho$ (thanks to $D{D}^{\ast }$ loops mediating this decay channel). At the same time, we aim to determine the pole position and the properties of the charmonium seed state: quite interestingly, even if a pole is always present, it is possible that there is no peak corresponding to this state in the spectral function, thus potentially explaining why the corresponding resonance could not yet be seen in experiments.

Large vorticities in the Quark–Gluon Plasma produced in peripheral collisions studied by the STAR collaboration at the RHIC facility have been deduced from observations of polarizations of $\mathrm{\Lambda }$ and $\bar{\mathrm{\Lambda }}$ hyperons. Recently, the STAR collaboration has reported on the dependence of these polarizations on centrality, at impact energy 200 GeV and relatively large centralities ${𝒞}\ge 20\%$. The polarizations increase slowly with centrality, up to perhaps ${𝒞}=60\text{–}70\%$. Here we use a holographic model of the vortical QGP to make predictions regarding these polarizations for smaller centralities, ranging from 5–20%. The model predicts that as one moves downwards from 20%, $\mathrm{\Lambda }/\bar{\mathrm{\Lambda }}$ polarizations at first decrease but then increase sharply, in a characteristic pattern which should be readily detected if collisions can be studied at impact energies below 200 GeV and centrality as low as 5–10%. The effect should be most evident at moderate impact energies below 200 GeV, so we give predictions for impact energy 27 GeV.

A phenomenological model with active and sterile neutrinos is used for calculations of neutrino oscillation characteristics at the normal mass hierarchy of active neutrinos. Taking into account the contributions of sterile neutrinos, appearance and survival probabilities for active neutrinos are calculated. Modified graphical dependencies for the probability of appearance of electron neutrinos/antineutrinos in muon neutrino/antineutrino beams as a function of the ratio of the distance to the neutrino energy and other model parameters are obtained. It is shown that in the case of a certain type mixing between active and sterile neutrinos it is possible to describe all anomalies of neutrino data at short distances with the same model parameters. A new parametrization for a particular type mixing matrix of active and sterile neutrinos that takes into account the additional sources of CP violation is used. The comparison with the existing experimental data is performed and, using this knowledge, the estimates of some model parameters are found. The theoretical results obtained for mixing of active and sterile neutrinos can be applied for interpretation and prediction of results of ground-based experiments on search of sterile neutrinos as well as for the analysis of some astrophysical data.

We report a holographic study of a two-dimensional dilaton gravity theory with the Dirichlet boundary condition for the cases of nonvanishing and vanishing cosmological constants. Our result shows that the boundary theory of the two-dimensional dilaton gravity theory with the Dirichlet boundary condition for the case of nonvanishing cosmological constants is the Schwarzian term coupled to a dilaton field, while for the case of vanishing cosmological constant, a theory does not have a kinetic term. We also include the higher derivative term $R^2$, where $R$ is the scalar curvature that is coupled to a dilaton field. We find that the form of the boundary theory is not modified perturbatively. Finally, we show that a lattice holographic picture is realized up to the second-order perturbation of boundary cutoff ${𝜖}^2$ under a constant boundary dilaton field and the nonvanishing cosmological constant by identifying the lattice spacing $a$ of a lattice Schwarzian theory with the boundary cutoff $𝜖$ of the two-dimensional dilaton gravity theory.

In this paper, we extend the theory of the $q$-deformed quantum mechanics in one dimension${}^{21}$ into three-dimensional case. We relate the $q$-deformed quantum theory to the quantum theory in a curved space. We discuss the diagonal metric based on $q$-addition in the Cartesian coordinate system and core radius of neutron star. We also discuss the diagonal metric based on $q$-addition in the spherical coordinate system and $q$-deformed Heisenberg atom model.

The proton accelerator of the China Initiative Accelerator Driven Subcritical System (CiADS) adopts the continuous wave (CW) and superconducting technical route, and it may accelerate 5 mA proton beam to 500 MeV in energy. In this paper, the baseline physics design of the superconducting section (SC) and some design choices are discussed, and the error study results are also presented.

In this paper, we study the behavior of static spherically symmetric relativistic model of the strange star SAX J1808.4-3658 by exploring a new exact solution for anisotropic matter distribution. We analyze the comprehensive structure of the space–time within the stellar configuration by using the Einstein field equations amalgamated with quadratic equation of state (EoS). Further, we compare solutions of quadratic EoS model with modified Bose–Einstein condensation EoS and linear EoS models which can be generated by a suitable choice of parameters in quadratic EoS model. Subsequently, we compare the properties of strange star SAX J1808.4-3658 for all the three EoS models with the help of graphical representations.

We investigate the particle–antiparticle symmetry of the gravitationally coupled Dirac equation, both on the basis of the gravitational central-field problem and in general curved space–time backgrounds. First, we investigate the central-field problem with the help of a Foldy–Wouthuysen transformation. This disentangles the particle from the antiparticle solutions, and leads to a “matching relation” of the inertial and the gravitational mass, which is valid for both particles as well as antiparticles. Second, we supplement this derivation by a general investigation of the behavior of the gravitationally coupled Dirac equation under the discrete symmetry of charge conjugation, which is tantamount to a particle$\to$antiparticle transformation. Limitations of the Einstein equivalence principle due to quantum fluctuations are discussed. In quantum mechanics, the question of where and when in the Universe an experiment is being performed can only be answered up to the limitations implied by Heisenberg’s Uncertainty Principle, questioning an assumption made in the original formulation of the Einstein equivalence principle. Furthermore, at some level of accuracy, it becomes impossible to separate nongravitational from gravitational experiments, leading to further limitations.