arXiv subjects

Daniil Stepanenko

Publications and source records attributed to Daniil Stepanenko.

5 recordsLinked to original sources

arXiv2026

Scattering and Tunneling in Real Quantum Mechanics

We establish the general form of the evolution equation and study scattering and tunneling in real quantum mechanics. We prove an analogue of Stone's theorem for a real Kahler space and derive the corresponding general evolution equation, whose evolution operator is both orthogonal and symplectic. We formulate scattering theory in terms of real wave operators and the associated S-matrix. For the class of potentials considered, we show that the differential scattering cross section is equivalent to that obtained in standard complex quantum mechanics. We also show that the tunneling probability in real quantum mechanics is identical to that in complex quantum mechanics.

quant-ph↗

arXiv2026

EMRI Dephasing from a Torsion-Inspired Near-Zone Kerr Deformation: Motivated by Spin-Polarized Dark Matter

Extreme-mass-ratio inspirals (EMRIs) are sensitive probes of weak conservative perturbations in the strong-field region of massive black holes. We study a phenomenological EMRI model motivated by Einstein--Cartan gravity in which a spin-polarized dark-matter spike is described by a Weyssenhoff fluid. After torsion is eliminated algebraically, the local spin contribution contains a repulsive exterior source $U_{tt}^{\rm spin}\propto-\sigma_0^2/r^3$. Solving the corresponding static linearized field equation, however, does not produce a global $1/r^3$ metric perturbation; the response contains a mass renormalization, a logarithmic $r^{-1}$ tail, and an $M/r^2$ term. We therefore introduce $g_{\mu\nu}^{\rm eff}=g_{\mu\nu}^{\rm Kerr}+\alpha h_{\mu\nu}^{\rm eff}$ only as a local near-zone matching ansatz, not as a complete rotating Einstein--Cartan black-hole solution. Within this torsion-inspired deformation we compute circular equatorial inspirals and analytic-kludge waveforms. The fiducial model can produce large phase shifts in an idealized adiabatic calculation, but the forecast is optimistic and does not include a full LISA/Taiji response, Teukolsky/self-force fluxes, eccentricity, inclination, or high-dimensional parameter degeneracies. The results should be read as constraints on an effective near-zone operator rather than as a prediction of minimally coupled Einstein--Cartan dark matter.

gr-qc↗

arXiv2024

Black Brane/Bose Gase Duality and Third Law of Thermodynamics

In the thermodynamics of black holes in asymptotically flat space, the third law of thermodynamics is violated, and entropy cannot be consistently modeled through conventional statistical mechanics. Notably, the third law of thermodynamics is violated for the Schwarzschild black hole, and its entropy can only be described using an unconventional model, such as a Bose gas in negative dimensions. In contrast, for certain black brane solutions such as Poincare AdS black branes, Lifshitz black branes, and anisotropic Lifshitz-type black branes, the third law is preserved, with entropy vanishing as temperature approaches zero. In this paper, we extend the previously established duality between black hole and Bose gas thermodynamics to black branes. Specifically, the Poincare black brane in $D$ spacetime dimensions corresponds to a non-relativistic Bose gas in $2(D-2)$ spatial dimensions. Furthermore, the duality between Lifshitz branes and Bose gases relates a Lifshitz brane with exponent $\alpha$ in $D$-dimensional spacetime to a Bose gas of quasi-particles with energy $k^\alpha$ in $D-2$ spatial dimensions.

hep-th↗

arXiv2023

No Violation of Bell-CHSH Inequalities at Large Distances

The usual derivation of the violation of Bell-type inequalities can be applied actually only for small distances between detectors. It does not take into account the dependence of the quantum mechanical wave function on space-time variables. We study the behavior of entangled photons obtained in spontaneous parametric down-conversion (SPDC) experiments and show that at large distances there is in fact no violation of the Bell-CHSH inequalities. We show that the initial entangled states become disentangled at large space-like distances. This does not contradict the violation of Bell inequalities observed at small distances between detectors. We propose an experiment to study the dependence of the quantum correlation function and Bell value on increasing distance between detectors. We predict that these quantities decrease inversely proportional to the increase of the distance between the detectors.

quant-ph↗

arXiv2022

Schwarzschild black holes, Islands and Virasoro algebra

The Schwarzschild black hole metric with mass $M$ has the limit of the vanishing mass when one get the Minkowski space. We study behavior of the entanglement entropy by using the island formula and the limit of the vanishing black hole mass. The black hole information problem appears if one considers the lowering its mass. It was noted recently that the formula derived for eternal black holes leads to an increase of the entanglement entropy, which is singular when $M \to 0$. In this process, it arises the other problem of the Schwarzschild black hole explosion, as the black hole temperature blows up as the mass vanishes.We show that it is possible to solve the entropy explosion for small masses, if one admit the following bound: $c<AM$ where $c$ is central charge of the Virasoro algebra, M is black hole mass and A is positive constant. We are examining the possibilities of applying such a mechanism to calculate entropy with and without an island. It was shown that applying the mechanism of the dependence of the central charge on the black hole mass allows us to obtain a similar Page curve without using an island.

hep-th↗