Modern Physics Letters A

In this paper, we study thermodynamic curvature of Chaplygin gas which is one of the dark energy candidates in terms of entropy and temperature. So, we get some information about past universe by considering thermodynamic curvature of Chaplygin gas. In addition to thermodynamic curvature, we study behaviors of test particle in the universe filled with Chaplygin gas.

In this paper, we provide five canonical and three Lie-algebraic twist-deformations of Carroll, para-Galilei and Static Hopf algebras. Particularly, in the case of Carroll Hopf structure, we get the same result with the use of contraction schemes of corresponding canonically and Lie-algebraically twisted Poincaré Hopf algebras as well.

We study the trajectories of photons in modified Hayward black hole spacetime. Three kinds of horizons are distinguished by analyzing the lapse function of modified Hayward black hole spacetime. Through plotting the effective potential with different values of parameters, it is found that the parameter $b$ has more conspicuous effects than parameters $\alpha$ ($\alpha$ is associated with the time-delay) and $\beta$ ($\beta$ is related to the 1-loop quantum corrections) for the effective potential. The change of the parameters ($\alpha$, $\beta$ and $b$) has an obvious influence on unstable circular orbits. The structure of null geodesic is simpler than that of time-like geodesic. The stable circular orbits and the bound orbits are not included for the photon trajectories. By analyzing the corresponding effective potential, all possible orbits of null geodesic are found. The radius of unstable circular orbit equals 2.8790 for fixed $\ell =0.60M$, $b=4.00M$, $\alpha =0.50$, $\beta =1.00$ and $M=1.00$.

In this paper, we solved the Schrödinger equation in the commutative and non-commutative (NC) spaces under the presence of magnetic field. In other words, we obtained the energy spectrum and wave functions in terms of Heun functions. When we considered the case $𝜃\to 0$, we observed that the NC space converts to the commutative space.

In this paper, we study the tunneling of charged fermions from the stationary axially symmetric black holes using the generalized uncertainty principle (GUP) via Wentzel, Kramers, and Brillouin (WKB) method. The emission rate of the charged fermions and corresponding modified Hawking temperature of Kerr–Newman black hole, Einstein–Maxwell-dilaton-axion (EMDA) black hole, Kaluza–Klein dilaton black hole, and then, charged rotating black string are obtained and we show that the corrected thermal spectrum is not purely thermal because of the minimal scale length which cause the black hole’s remnant.

The degree of second-order coherence of the relic gravitons produced from the vacuum is super-Poissonian and larger than in the case of a chaotic source characterized by a Bose–Einstein distribution. If the initial state does not minimize the tensor Hamiltonian and has a dispersion smaller than its averaged multiplicity, the overall statistics is by definition sub-Poissonian. Depending on the nature of the sub-Poissonian initial state, the final degree of second-order coherence of the quanta produced by stimulated emission may diminish (possibly even below the characteristic value of a chaotic source) but it always remains larger than one (i.e. super-Poissonian). When the initial statistics is Poissonian (like in the case of a coherent state or for a mixed state weighted by a Poisson distribution) the degree of second-order coherence of the produced gravitons is still super-Poissonian. Even though the quantum origin of the relic gravitons inside the Hubble radius can be effectively disambiguated by looking at the corresponding Hanbury Brown–Twiss correlations, the final distributions caused by different initial states maintain their super-Poissonian character which cannot be altered.

A series of successive quantizations is considered, starting with the quantization of a non-relativistic or relativistic point particle: (1) quantization of a particle’s position, (2) quantization of wave function, (3) quantization of wave functional. The latter step implies that the wave packet profiles forming the states of quantum field theory are themselves quantized, which gives new physical states that are configurations of configurations. In the procedure of quantization, instead of the Schrödinger first-order equation in time derivative for complex wave function (or functional), the equivalent second-order equation for its real part was used. In such a way, at each level of quantization, the equation a quantum state satisfies is just like that of a harmonic oscillator, and wave function(al) is composed in terms of the pair of its canonically conjugated variables.

In this paper, the transverse momentum and maximum transverse momentum distributions of protons and pions produced in an event for CC collisions at 4.2 A GeV/c have been analyzed. This analysis is based on experimental data obtained from 2 m propane bubble chamber at Joint Institute for Nuclear Research, Dubna, Russia and simulation data obtained from Dubna cascade code. We observed three disparate zones for the transverse momentum distribution of the produced particles. The third zone where transverse momentum is greater than 0.375 GeV/c is restricted only for pions with transverse momentum approximately equal to 1 GeV/c, and for protons the restricted value of $p_T$ is $\sim$1.5 GeV/c. So contribution of pions to this region is less and decreases sharply than the contribution of protons. The results of cascade model are not fully compatible with the experimental results in the third $p_T$ region, as this region contains less number of particles for model data as compared with experimental data but is compatible in the case of ${p{}_T}_{max}$.

It is well-known that traversable wormholes are valid solutions of the Einstein field equations, but these structures can only be maintained by violating the null energy condition. In this paper, we have obtained such wormhole solutions in an isothermal galactic halo, as well as in a void. We have shown that the null energy condition is violated, with the help of a suitable redshift function obtained from flat galactic rotation curves.