International Journal of Theoretical Physics最新文献

We introduce a new type of quantum state called the Hermite Polynomial Squeezed Coherent State (HPSCS). First, we derive the normalization factor of the HPSCS and compare its statistical properties. The Wigner function of the HPSCS is derived explicitly. The nonclassical properties of the HPSCS are explored through its photon number distribution, Mandel parameter, second-order correlation function, and the negativity of the Wigner function. The mathematical and physical properties are also studied.

In this paper, we address the phase space formulation of the Jaynes–Cummings model through the explicit construction of the full Wigner function for a hybrid bipartite quantum system composed of a two-level atom and a quantized coherent field. By employing the Stratonovich–Weyl correspondence and the coadjoint orbit method, we derive an informationally complete quasi-probability distribution that captures the full dynamics of light–matter interaction. This approach provides a detailed phase space perspective of fundamental quantum phenomena such as Rabi oscillations, atomic population inversion, and entanglement generation. We further measure the purity of the reduced quantized field state by means of an appropriate Wigner function corresponding to the bosonic field part in order to investigate the entanglement dynamics of the system.

In this work, we introduce a novel state-dependent quantum cloning (copying) process by introducing a new class of ancillary system—an adaptive ancilla—modifying the conventional state-dependent quantum copying process. This state-dependent ancillary system is not pre-engineered to match the quantum state to be cloned, rather it dynamically aligns with the quantum state to be cloned via interaction. However, the space of states that it can clone is restricted by the symmetry principles. This process, while resembling quantum cloning, adheres to the no-cloning theorem due to its state-dependent and non-universal nature. Also, no-cloning theorem does not forbid the possibility that the information required to construct a clone pre-exist in any implicit form but forbids the construction of a new copy using single universal cloning machine or the existence of a hidden copy. We clarify the distinction between universal copying and conditional copying, and also between state-dependent copying via pre-engineered ancilla and via adaptive ancilla. We demonstrate that stimulated emission offers a concrete physical realization of state-dependent quantum copying via adaptive ancilla. We explore how a quantum state, for instance a photon polarization, can be cloned through light-matter interactions when the ancillary system, such as an excited atom, contain an implicit structural information about the quantum state in the form of structured set of dynamical response channels. We reinterpret the excited atomic state as a realization of an adaptive ancilla and cloning of a photon polarization state occurs when the quantum state of an excited atom dynamically aligns with the polarization state of the photon through physical interaction. We demonstrate that the true limits of cloning arise solely not from the no-cloning theorem, but from the symmetries imposed on physical systems—constraints which may, in principle, be relaxed or engineered in suitable quantum systems, for instance in Rydberg atoms.

This work investigates dispersion-driven lump wave structures within a generalized (2+1)-dimensional Calogero–Bogoyavlenskii–Schiff-like framework. By employing a generalized bilinear form of the governing equation, we construct positive quadratic function solutions via symbolic computation, which in turn generate lump wave structures. The analysis shows that the stationary points of the quadratic function align along a straight trajectory in the spatial plane and propagate with constant velocity, where the lump amplitude vanishes. The emergence of these lump waves results from the interplay of eight nonlinear terms and four dispersion terms in the model.

We investigate the concept of macroscopically distinguishable superpositions within an infinite array of boson sites. Our approach is rigorous within the frame of Hilbert space theory. In this context, it is natural to differentiate between states–and corresponding dynamics–that involve only finitely many degrees of freedom, referred to as local, and those that are inherently nonlocal. Previous studies have shown that such systems can support nonlocal coherent states (NCS). In this work, we demonstrate that NCS can dynamically evolve into nonlocal cat states under the influence of a nonlocal Hamiltonian–specifically, the square of the total number operator. Crucially, the resulting dynamics cannot be decomposed into local factors. Furthermore, we explore broader mathematical implications of these phenomena within the framework of generalized bosons. Our findings highlight that the concepts of coherent states and nonlocal cat states are not inherently bound together; rather, their fusion is a distinctive feature of standard bosons. Finally, we propose that if the generalized boson framework can be physically realized in engineered quantum systems, the phenomena described here may hold significant relevance for both physics and materials science.

We demonstrate that the interference effects observed in the double-slit experiment can be explained by our recently developed theory of critical relativistic nonlinear fields. Within this framework, there is no mysterious “duality” at all as particles are just field resonances highly localized in space-time that occur as critical transitions in waves initially of infinite spatial and temporal extent. As such, observed wave-like interference effects of ’particles’ in not mysterious, but rather expected.

In canonical quantum gravity, time does not appear as a fundamental coordinate, posing the longstanding problem of how dynamical evolution arises in a fundamentally timeless universe. In this work, we propose that entropy—interpreted as a coarse-grained, monotonically increasing measure of system complexity—can serve as an emergent internal clock. We unify three complementary mechanisms underpinning this idea: (i) the monotonic growth of entanglement entropy under unitary dynamics, (ii) thermal modular flow associated with Kubo-Martin-Schwinger states, and (iii) relational time from the Page–Wootters framework. These mechanisms jointly define a physical arrow and parametrization of time grounded in the informational structure of the quantum state. From this foundation, we derive explicit entropic time laws of the form (tau (Delta S)=left( Delta S/lambda right) ^{1/gamma }), showing how the parameters ((q,N_{0},lambda ,gamma )) emerge from microscopic statistical properties such as non-extensive correlations, phase space growth, and entropy production rates. We apply this framework to cosmological epochs, identifying entropy increase across inflation, radiation and matter domination as a natural proxy for internal time progression. This entropic approach provides a unified view linking quantum foundations, thermodynamic irreversibility, and cosmological evolution. We also discuss interpretational subtleties, clarifying how entropic time differs from coordinate time and under what conditions it defines a meaningful temporal structure. We emphasize that the entropic time, (tau ,) provides an arrow and parametrization of change in relational regimes (Wheeler–DeWitt,Page–Wootters, KMS/modular frameworks), but it is not proposed as a universal bijective substitute for coordinate time, t.

Recently, Padmanabhan has argued that a difference between the number of degrees of freedom on the surface and the number in a bulk causes the expansion of the universe. We can reconsider this idea in a BIon system. A Bion is formed from two branes that are connected by a wormhole. Our universe may live on one of these branes. Each brane could be formed from joining lower-dimensional branes like (D_1) ones. By joining (D_1) branes, a (D_n) brane is formed, and some amounts of energy are released. Then, maybe some dimensions are compacted, and some other amount of energy is released. These energies cause a significant difference between the number of degrees of freedom on the surface and in the bulk of branes. This causes the evolution of the universe and many changes in thermodynamic parameters like the entropy and cosmic parameters like the Hubble constant. We obtain the standard form of the Hubble parameter and its dependency on redshift in a Bion system.

This paper is devoted to the study of a non-isothermal phase-field model to describe the microstructure evolution for sea-ice growth. The model consists of a system of non-linear parabolic equations. The existence of global weak solutions to an initial-boundary value problem of this model is established by means of the Galerkin method and the energy method. The uniqueness and regularity are also studied under certain conditions on the nonlinearities. Moreover, we show that the model has a bounded absorbing set. Finally, a numerical calculation is performed, which reveals dendritic growth morphology in the solid-liquid interface during solidification of seawater.

In this paper, we extend Nelson’s stochastic mechanics to a fractal time framework using fractal calculus. By modeling quantum particle motion with fractal stochastic differential equations, we define forward, backward, and osmotic velocities and derive the fractal Fokker-Planck equation. Introducing a fractal complex wave function, we rigorously derive the fractal Schrödinger equation, revealing how quantum behavior can emerge from stochastic dynamics in fractal time.