共查询到20条相似文献,搜索用时 31 毫秒
1.
V. P. Koscheev 《Russian Physics Journal》1991,34(8):717-721
Using the quantum theory of channeling, the problem of determining the coherence length is solved, starting with which the off-diagonal elements of the density matrix are attenuated. In the general case, the populations of the quantum states are calculated, which determine the probability density of transitions of channeled particles from a discrete into a continuous spectrum as a function of the penetration depth.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 83–87, August, 1991. 相似文献
2.
S. A. Beznosyuk 《Russian Physics Journal》1994,37(8):750-756
Euler's equations for quantum rheology and the confinement of electrons in a system of active centers of nanometric scale of a condensed state are obtained using the formalism of kinematic electron-density waves. The conditions for the stability of the electron quantum walls of confinement in the form of the balance between the forces of electric and quantum nature are analyzed.E. A. Buketov Karagandinsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 60–67, August, 1994. 相似文献
3.
E.B. Karlsson 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(3):393-400
The coherence in quantum superposition states of protons (and chemically similar particles, the positive muons) has been studied
in some condensed matter environments. It is shown that if the proton systems and the experimental techniques used to study
them are carefully selected, it is possible to observe quantum delocalization states of single particles and to understand
the mechanisms for their loss of coherence. Quantum correlated two- and multiparticle states of protons lose coherence very
fast when coupled to condensed matter environments, but new sub-femtosecond techniques have made them accessible to experimental
studies. The degree of decoherence can be measured as function of time and the decoherence mechanisms can, at least in certain
cases, be identified. Although less clean than in corresponding studies of quantum optical systems, these studies can be seen
as a first step towards understanding the conditions for preservation of quantum correlation and entanglement in massive systems.
Some consequences and some suggestions for future work are discussed.
Received 28 August 2002 Published online 7 January 2003 相似文献
4.
The explicit form of relativistic, energy-dependent interaction operators for a composite system of N scalar particles in
the second order of perturbation theory is obtained within the framework of the simultaneous covariant approach of quantum
field theory on the basis of the retarding part of two-time Green's functions. Explicitly covariant equations for the wave
function of the bound state and the conditions for its normalization are obtained.
Frantsiska Skorina State University, Gomel'. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 17–24,
August, 1997. 相似文献
5.
M. Mühlbauer H. Daniel F.J. Hartmann P. Hauser F. Kottmann C. Petitjean W. Schott D. Taqqu P. Wojciechowski 《Hyperfine Interactions》1999,119(1-4):305-310
The classical methods used in beam cooling are hard to be adapted for a beam of short-lived elementary particles. A novel
method, the so-called frictional cooling – that is cooling a beam of low-energy charged particles by moderation in matter
and acceleration in an electrostatic field – has been shown to be feasible. In our experiments performed in 1994/1995 a beam
of short-lived particles was cooled for the first time ever. Utilizing frictional cooling on a beam of slow negative muons
we observed increase in phase space density by about one order of magnitude.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
A. Ya. Silenko 《Journal of Experimental and Theoretical Physics》1998,87(2):246-250
The Dirac-Pauli equation is used to obtain the exact equation of spin motion for spin-1/2 particles with an anomalous magnetic
moment in a constant and uniform magnetic field. Exact formulas are established for the angular velocity of the revolution
of such particles along circular orbits and the rotation of the particle spin with respect to momentum. Finally, a quantum
mechanical equation for the motion of the particles in a strong magnetic field is derived.
Zh. éksp. Teor. Fiz. 114, 448–457 (August 1998) 相似文献
7.
8.
Stochastic realization of the wave function in quantum mechanics with the inclusion of soliton representation of extended
particles is discussed. Two-soliton configurations are used for constructing entangled states in generalized quantum mechanics
dealing with extended particles, endowed with nontrivial spin S. Entangled solitons construction being introduced in the nonlinear spinor field model, the Einstein-Podolsky-Rosen (EPR) correlation
is calculated and shown to coincide with the quantum mechanical one for the 1/2-spin particles. The concept of stochastic
qubits is used for quantum computing modeling.
The text was submitted by the authors in English. 相似文献
9.
Diederik Aerts 《International Journal of Theoretical Physics》2010,49(12):2950-2970
We elaborate an interpretation of quantum physics founded on the hypothesis that quantum particles are conceptual entities
playing the role of communication vehicles between material entities composed of ordinary matter which function as memory
structures for these quantum particles. We show in which way this new interpretation gives rise to a natural explanation for
the quantum effects of interference and entanglement by analyzing how interference and entanglement emerge for the case of
human concepts. We put forward a scheme to derive a metric based on similarity as a predecessor for the structure of ‘space,
time, momentum, energy’ and ‘quantum particles interacting with ordinary matter’ underlying standard quantum physics, within
the new interpretation, and making use of aspects of traditional quantum axiomatics. More specifically, we analyze how the
effect of non-locality arises as a consequence of the confrontation of such an emerging metric type of structure and the remaining
presence of the basic conceptual structure on the fundamental level, with the potential of being revealed in specific situations. 相似文献
10.
The electron spin resonance (ESR) spectrometer, a very sensitive instrument with fast detecting window to explore quantum phase transitions for magnetic nanoparticles, was exploited to study the fascinating interplay between thermal and quantum fluctuations in the vicinity of a quantum critical point. We have measured ESR in ferrofluid samples containing nanosize particles of Fe2O3. The evolution of the ESR spectrum with temperature suggests that quantum tunneling of spins occurs in single domain magnetic particles in the low temperature regime. The effects of various microwave fields, particle sizes, and temperatures on the magnetic states of single domain spinel ferrite nanoparticles are investigated. We can consistently explain experimental data assuming that, as the temperature decreases, the spectrum changes from superparamagnetic (SPR) to blocked SPR and finally evolves quantum superparamagnetic behaviour as the temperature lowers down further. A nanoparticle system of a highly anisotropic magnetic material can be qualitatively specified by a simple quantum spin model, or by the Heisenberg model with strong easy-plane anisotropy.Received: 29 August 2003, Published online: 15 October 2003PACS:
76.30.-v Electron paramagnetic resonance and relaxation - 75.40.Cx Static properties (order parameter, static susceptibility, heat capacities, critical exponents, etc.) - 05.30.-d Quantum statistical mechanics - 75.50.Dd Nonmetallic ferromagnetic materials 相似文献
11.
C. Wetterich 《Annalen der Physik》2010,522(11):807-848
Quantum particles and classical particles are described in a common setting of classical statistical physics. The property of a particle being “classical” or “quantum” ceases to be a basic conceptual difference. The dynamics differs, however, between quantum and classical particles. We describe position, motion and correlations of a quantum particle in terms of observables in a classical statistical ensemble. On the other side, we also construct explicitly the quantum formalism with wave function and Hamiltonian for classical particles. For a suitable time evolution of the classical probabilities and a suitable choice of observables all features of a quantum particle in a potential can be derived from classical statistics, including interference and tunneling. Besides conceptual advances, the treatment of classical and quantum particles in a common formalism could lead to interesting cross‐fertilization between classical statistics and quantum physics. 相似文献
12.
Marco Nizama Manuel O. Cáceres 《The European Physical Journal B - Condensed Matter and Complex Systems》2017,90(9):164
Quantum correlations between two free spinless dissipative distinguishable particles (interacting with a thermal bath) are studied analytically using the quantum master equation and tools of quantum information. Bath-induced coherence and correlations in an infinite-dimensional Hilbert space are shown. We show that for temperature T> 0 the time-evolution of the reduced density matrix cannot be written as the direct product of two independent particles. We have found a time-scale that characterizes the time when the bath-induced coherence is maximum before being wiped out by dissipation (purity, relative entropy, spatial dispersion, and mirror correlations are studied). The Wigner function associated to the Wannier lattice (where the dissipative quantum walks move) is studied as an indirect measure of the induced correlations among particles. We have supported the quantum character of the correlations by analyzing the geometric quantum discord. 相似文献
13.
14.
P. V. Dvornikov 《Russian Physics Journal》2005,48(8):839-847
Consideration of quantum field theory in the pseudo-Finsleroid space leads to the occurrence of corrections to expressions
for scattering cross sections of interacting particles. Such corrections are presented for certain elementary processes. The
calculation method is based on the proper generalization of the S-matrix, T-product, and the Green's functions.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 52–58, August, 2005. 相似文献
15.
C. Wetterich 《Physics letters. A》2012,376(5):706-712
We describe both quantum particles and classical particles in terms of a classical statistical ensemble, with a probability distribution in phase space. By use of a wave function in phase space both can be treated in the same quantum formalism. Quantum particles are characterized by a specific choice of observables and time evolution of the probability density. Then interference and tunneling are found within classical statistics. Zwitters are (effective) one-particle states for which the time evolution interpolates between quantum and classical particles. Experimental bounds on a small parameter can test quantum mechanics. 相似文献
16.
The classical partition function for a system in thermodynamical equilibrium formed by N identical non-relativistic particles interacting through Coulomb potentials and with the dynamical electromagnetic field is studied. It is proved that the dynamical or transverse EM degrees of freedom decouple from the particle ones. It is also shown that this decoupling does to take place in the quantum mechanical partition function. The leading quantum corrections to the classical partition function are explicitly given. Such corrections are shown to be determined by instantaneous dipole-dipole coulombic interactions and by self-energy effects, and to receive no contribution from the interaction among different particles mediated by the dynamical EM field. 相似文献
17.
18.
Alexey V. Melkikh 《理论物理通讯》2015,64(1):47-53
The problem of the wave function collapse (a problem of measurement in quantum mechanics) is considered. It is shown that it can be solved based on quantum mechanics and does not require any additional assumptions or new theories. The particle creation and annihilation processes, which are described based on quantum field theory, play a key role in the measurement processes. Superposition principle is not valid for the system of equations of quantum field theory for particles and fields, because this system is a non-linear. As a result of the creation (annihilation) of a particle, an additional uncertainty arises, which "smears" the interference pattern. The imposition of such a large number of uncertainties in the repetitive measurements leads to the classical behavior of particles. The decoherence theory also implies the creation and annihilation of particles, and this processes are the consequence of non-linearity of quantum mechanics. In this case, the term "collapse of the wave function" becomes a consequence of the other statements of quantum mechanics instead of a separate postulate of quantum mechanics. 相似文献
19.
《理论物理通讯》2015,(7)
The problem of the wave function collapse(a problem of measurement in quantum mechanics) is considered.It is shown that it can be solved based on quantum mechanics and does not require any additional assumptions or new theories. The particle creation and annihilation processes, which are described based on quantum field theory, play a key role in the measurement processes. Superposition principle is not valid for the system of equations of quantum field theory for particles and fields, because this system is a non-linear. As a result of the creation(annihilation) of a particle,an additional uncertainty arises, which "smears" the interference pattern. The imposition of such a large number of uncertainties in the repetitive measurements leads to the classical behavior of particles. The decoherence theory also implies the creation and annihilation of particles, and this processes are the consequence of non-linearity of quantum mechanics. In this case, the term "collapse of the wave function" becomes a consequence of the other statements of quantum mechanics instead of a separate postulate of quantum mechanics. 相似文献
20.
Y. Shih 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(3):485-493
One of the most surprising consequences of quantum mechanics is the entanglement of two or more distant particles. Even though
we still have questions in regard to fundamental issues of the entangled quantum systems, quantum entanglement has started
to play important roles in practical applications. Quantum imaging is one of the hot topics. Quantum imaging has many interesting
features which are useful for different applications. For example, quantum imaging can be nonlocal, which is useful for secure
two-dimensional information transfer. Quantum imaging can reach a much higher spatial resolution comparing with classical
imaging, even beyond the diffraction limit, which is useful for lithography and other microsystem fabrication technology.
It is not a violation of the uncertainty principle, however, a quantum mechanical multi-particle phenomenon.
Received 30 August 2002 / Received in final form 11 November 2002 Published online 4 February 2003 相似文献