Position measurements in the de Broglie–Bohm interpretation of quantum mechanics

The de Broglie–Bohm interpretation of quantum mechanics assigns positions and trajectories to particles. We analyze the validity of a formula for the velocities of Bohmian particles which makes the analysis of these trajectories particularly simple. We apply it to particle detectors of four different types and show that the detectors of three of these types lead to “surrealistic trajectories”, i.e., leave a trace where the Bohmian particle was not present.     

The revival of Schrödinger's interpretation of quantum mechanics

A distinction is made between two wave functions(x) and(x), The former describing a continuous distribution of electronic matter for a single system, the latter describing the regularities in repeated experiments. The classical field(x) necessarily includes the self energy and accounts for all the radiative processes without the probability interpretation.     

Unprovability of a “precognition” effect in quantum mechanics

It is shown that nonlocality gives rise to an undecidable proposition, meaning it cannot be proved true nor proved false from the usual assumptions, but is independent of them. A variation on the usual thought experiment is considered in which the observers are timelike separated, but the nonlocality fails to become a precognition effect because of this independence result.     

Measurement and “beables” in quantum mechanics

It is argued that the measurement problem reduces to the problem of modeling quasi-classical systems in a modified quantum mechanics with superselection rules. A measurement theorem is proved, demonstrating, on the basis of a principle for selecting the quantities of a system that are determinate (i.e., have values) in a given state, that after a suitable interaction between a systemS and a quasi-classical systemM, essentially only the quantity measured in the interaction and the indicator quantity ofM are determinate. The theorem justifies interpreting the noncommutative algebra of observables of a quantum mechanical system as an algebra of beables, in Bell's sense.     

Observations of the Ramsauer–Townsend effect in quaternionic quantum mechanics

In this article, one of the well-known effects in quantum mechanics is addressed and also the extended form of quantum mechanics which is based on quaternions is presented. In the presence of this version of quantum mechanics the Ramsauer–Townsend effect has been investigated and the existence of this phenomenon is studied according to quaternionic calculations; results are presented by graphs.     

Combining relativity and quantum mechanics: Schrödinger's interpretation of ψ

The incongruence between quantum theory and relativity theory is traced to the probability interpretation of the former. The classical continium interpretation of removes the difficulty. How quantum properties of matter and light, and in particular the radiative problems, like spontaneous emission and Lamb shift, may be accounted in a first quantized Maxwell-Dirac system is discussed.     

Nucleon–nucleon scattering in the light of supersymmetric quantum mechanics

By exploiting supersymmetry-inspired factorization method together with a judiciously chosen deuteron ground-state wave function, approximate higher partial wave nucleon–nucleon potentials are generated. In this context, a minor modification is also introduced to the generated potentials. The n–p scattering phase shifts are computed and analysed via the phase function method.     

Gauge covariance of the Aharonov–Bohm phase in noncommutative quantum mechanics

The gauge covariance of the wave function phase factor in noncommutative quantum mechanics (NCQM) is discussed. We show that the naive path integral formulation and an approach where one shifts the coordinates of NCQM in the presence of a background vector potential leads to the gauge non-covariance of the phase factor. Due to this fact, the Aharonov–Bohm phase in NCQM which is evaluated through the path-integral or by shifting the coordinates is neither gauge invariant nor gauge covariant. We show that the gauge covariant Aharonov–Bohm effect should be described by using the noncommutative Wilson lines, what is consistent with the noncommutative Schrödinger equation. This approach can ultimately be used for deriving an analogue of the Dirac quantization condition for the magnetic monopole.     

Why “modal” interpretations of quantum mechanics don't solve the measurement problem

According to modal interpretations of quantum mechanics, an observable Q can possess a definite value even when the quantum state is not an eigenstate of Q. In this paper, I discuss some interpretive difficulties faced by modal theorists. First, expanding upon Albert and Loewer, I identify two reasons why real-life measurements are never ideal, and I discuss why these considerations bode ill for modal interpretations. Second, I show that modal interpretations provide a less satisfactory explanation of interference effects than is provided by pilot-wave interpretations.     

Can the breaking of time-reversal symmetry remove degeneracies in quantum mechanics?

Reduction of spatial symmetry can remove the degeneracy of energy levels in quantum mechanics. The break of time-reversal symmetry by inclusion of a dissipative environment can have a similar effect. The corresponding time-evolution of position and momentum fluctuations can be described by a nonlinear differential equation that can lead to bifurcations and, thus, splitting of energy levels.     

Entanglement between two atoms in the system of SchrSdinger cat state interacting with two entangled atoms

By the negative eigenvalues of partial transposition of density matrix, this paper investigates the time evolution of entanglement of the two entangled atoms in the system of two atoms interacting with SchrSdinger cat state. The result shows that the two atoms are always in the entanglement state, and the degree of entanglement between the two atoms exhibits ordinary collapses and revivals at 0.2 degree of entanglement, when the light field is large enough. On the other hand, the reinforcement of three different light fields on the degree of entanglement between two atoms is not evident.[第一段]     

The blossoming of quantum mechanics in Italy: the roots,the context and the first spreading in Italian universities (1900–1947)

The European Physical Journal H - The widespread positivist approach of physics research in Italy at the turn of the XIX and XX centuries did not provide a fertile ground for the scientific debate...     

Description of the shape evolution in the yrast states of ~（186）Pt

^186Pt was tested in the framework of IBM-1 and the X（3） model. The results show that ^186Pt is located close to the shape phase transition point, but the B（E2） values little agree with the X（3） model. The shape evolution in the yrast states of186Pt is also discussed in detail. TRS calculation exhibits a flat bottomed potential at low spin states, but a relatively deep minimum at high spin states. It suggests that a shape evolution from vibrational mode to rotational mode happens in ^186Pt. The result is in agreement with the E-GOS calculation.     

Form factors in the “point form” of relativistic quantum mechanics: Single- and two-particle currents

Electromagnetic and Lorentz-scalar form factors are calculated for a bound system of two spin-less particles exchanging a zero-mass scalar particle. Different approaches are considered including solutions of a Bethe-Salpeter equation, a point form approach to relativistic quantum mechanics and a non-relativistic one. The comparison of the Bethe-Salpeter results, which play the role of an experiment here, with the ones obtained in point form in single-particle approximation, evidences sizable discrepancies, pointing to large contributions from two-body currents in the latter approach. These ones are constructed using two constraints: ensuring current conservation and reproducing the Born amplitude. The two-body currents so obtained are qualitatively very different from standard ones. Quantitatively, they turn out not to be sufficient to remedy all the shortcomings of the point form form factors evidenced in impulse approximation.Received: 3 July 2003, Revised: 28 October 2003, Published online: 23 July 2004PACS: 11.10.St Bound and unstable states; Bethe-Salpeter equations - 13.40.Gp Electromagnetic form factors - 12.39.Ki Relativistic quark modelL. Theußl: Present address: TRIUMF, 4004 Wesbrook Mall, Vancouver, B.C., Canada, V6T 2A3     

Critical assessment of the Schrödinger picture of quantum mechanics

We provide an example in which the Heisenberg and the Schrödinger pictures of quantum mechanics give different results, thus confirming the statement of P.A.M. Dirac that the two pictures may lead to inequivalent results. We consider a one-dimensional nonrelativistic charged harmonic oscillator (frequency ω₀ and mass m), and take into account the action of the radiation reaction and the vacuum electromagnetic forces on the charged oscillator. We show that the Heisenberg picture gives the correct value, ℏω₀/2, for the ground state energy of the harmonic oscillator in both cases of classical and quantized vacuum fields. In the case of the Schrödinger picture, considering classical vacuum fields, and using a simple calculation for the classical radiation reaction force that is valid in the limit of large mass (mc²⪢ℏω₀), we obtain the value ℏω₀ for the ground state energy of the harmonic oscillator. We show that the vacuum electromagnetic forces play a very important role in the understanding of this discrepancy.     

Aφ factory to investigate the foundations of quantum mechanics

A bound on theK oscillating parameter has been obtained by some models of nonlocality. In this paper we stress the fact that aø factory to test the CP-violating parameters in theK system can also probe, through correlated observations of two ⁰, the incompatibility between the quantum mechanics and these formulations of the local realism.     

Comment on the observability of the “collapse” of the wavefunction in quantum measurements

A recent suggestion of Home and Whitaker concerning a thought experiment designed to investigate the “collapse” of a quantum mechanical state in a measurement is criticized by pointing out a serious flaw in the proposition of these authors.