Abstract
On the basis of the canonical quantization procedure, the motion of a micro-particle in a viscous medium is considered, where the drag force consists of two components proportional to the ...first and second degrees of velocity, respectively. The wave function of a particle corresponding to its quantum coherent state is found using the quasi-classical approach. It is shown that due to the viscous of the medium, a static localized domain of the probability density is formed at relatively long times. It is shown that the parameters of this domain contain the information about the parameters of the particle on the input to medium.
Abstract
Based on the quasi-classical approximation, a general approach is proposed for constructing non-stationary quantum states of a charged particle in a magnetic field, when the dissipative ...forces of viscous friction and drag, proportional to the velocity and the square of the velocity, respectively, are also significant. The corresponding quasi-classical Green’s function is found, with the help of which the squeezed and coherent states of the particle are studied. It is shown that the dissipation and a magnetic field suppress the quantum properties of the particle. This is especially true for the transverse motion with respect to the magnetic field. Over time, the coherent and squeezed states transform into the same static state, which is characterized by a zero uncertainty of the transverse coordinates and an uncertainty of the longitudinal coordinate, which contains information about the initial velocity of the particle.
Abstract
A version of the quasi-classical approach is proposed, which makes it possible to describe the straight-line motion of a micro-particle in a bulk dissipative medium. From the side of the ...medium, the particle is acted upon by the force of viscous friction and the drag force, which are proportional to the velocity and the square of the velocity, respectively. In addition, an external conservative force is applied to the particle. The Green’s function of the particle and the quasi-classical coherent state in the form of a three-dimensional localized wave packet are found. It is shown that the translational motion of the wave packet is accompanied by a monotonic increase in the uncertainties of the particle coordinates up to certain maximum asymptotic values. Due to the drag force, these asymptotic uncertainties contain information about the corresponding initial uncertainties in the coordinates of the micro-particle, about its initial velocity, as well as about the external conservative force.
Abstract The quasi-classical dynamics of a charged particle in a weak magnetic field in the presence of dissipative losses caused by ionization of the medium is studied. The approximate approach ...proposed here is a generalization of the Caldirola—Kanai method for quantizing the translational motion of particles in dissipative media. It is shown that a weak curvature of a classical trajectory by the magnetic field is accompanied by an isotropic increase of uncertainty of the particle coordinates to the some maximum value at the moment the localized probability density wave packet stops. The limitation of the increase of coordinate uncertainty is due to irreversible ionization losses.
Abstract A self-consistent quasi-classical generalization of the axiomatic quantization of the translational motion of a particle in a dissipative medium is proposed, which is modeled by a drag force ...F d , which depends in a power-law manner on the velocity v : F d ∼ v n , where n is an arbitrary real number. A detailed analysis of the quasi-classical coherent state is carried out. It is shown that under condition n < 3 the dissipative medium suppresses the quantum properties of particle motion, performing the function of a classical measuring device. Otherwise, there is no suppression of quantum properties.
Abstract Based on the quasi-classical version of the canonical Caldirola–Kanai quantization, non-relativistic cyclotron resonance in a dissipative medium is studied. The corresponding particle ...propagator in the coordinate representation is found. It is shown that the combined effect of dissipation and a constant magnetic field reduces to the suppression of the quantum properties of a charged particle. In turn, a time-varying electric field that causes cyclotron resonance does not exhibit similar properties and does not affect the uncertainties of the particle coordinates.
Abstract
A quasi-classical approach is proposed for describing the motion of a charged particle in a magnetic field, taking into account irreversible losses due to the macroscopic viscosity of the ...medium. The wave function of a charged particle corresponding to its quasi-classical coherent state is found. It is shown that viscosity leads to an irreversible collapse of the wave function in directions perpendicular to the magnetic field. At the same time along the magnetic field the wave function experiences irreversible spreading up to a certain static limit. Thus, in the transverse directions a viscous medium and a magnetic field behave like a classical measuring device. In the longitudinal directions the signs of the quantum Zeno effect are visible. As a result of such anisotropic quantum dynamics the wave packet of the probability density takes the form of a thin filament wound around a magnetic field. The length of the filament is determined by the limiting value of the uncertainty of the longitudinal coordinate of the particle. In turn, this asymptotic uncertainty contains the information about its initial value, about the mass of the particle, and about the properties of the viscous medium.
Abstract
Based on the formalism of quasi-classical canonical quantization, the translational motion of a particle in a viscous medium is studied. The case is considered when, in addition to the ...resistance forces, an external conservative force acts on the particle. It is shown that due to the forces of viscous resistance of the medium, the initial coherent state of the particle does not decay. This behavior of the wave function is accompanied by a partial suppression of the quantum properties of the particle. In this case, a viscous medium should be considered as a classical device that continuously measures the state of a particle. Therefore, the stability of the coherent state of a particle can be interpreted as a manifestation of the quantum Zeno effect.
Relaxation echo Sazonov, S V
Laser physics letters,
05/2023, Volume:
20, Issue:
5
Journal Article
Peer reviewed
Abstract
The possibility of generation of a microwave echo-signal due to irreversible phase relaxation in a system of equidistant triplets with a cascade scheme of magnetic-dipole transitions is ...predicted. The disappearance of relaxation entails the disappearance of this echo-signal. The mechanism of this effect lies in the destructive interference of quantum transitions, which radiate in anti-phase with the same eigen-frequencies. The difference in phase relaxation times for these transitions leads to incomplete damping of the resulting coherence. As a result an echo-signal is generated.
