scholarly journals Position Indeterminacy

2000 ◽  
Vol 53 (5) ◽  
pp. 631 ◽  
Author(s):  
Fosco Ruzzene
Keyword(s):  
Quantum Mechanics ◽  
Dirac Equation ◽  
Standard Quantum ◽  
Helium Ion ◽  
Hydrogen Deuterium ◽  
Theory And Experiment

Calculations assuming position indeterminacy in the Dirac equation are reported.Energy shift contributions for low-lying states of hydrogen-like atoms are calculated by treating the position indeterminacy as a perturbation additional to standard quantum mechanics. The results are consistent with the current discrepancy between theory and experiment for Lamb shifts in hydrogen, deuterium and the helium ion.

scholarly journals Standard quantum mechanics without observers

2021 ◽  
Vol 103 (3) ◽  
Author(s):  
Ovidiu Cristinel Stoica
Keyword(s):  
Quantum Mechanics ◽  
Standard Quantum

scholarly journals Broadening quantum cosmology with a fractional whirl

2021 ◽  
pp. 2140005
Author(s):  
S. M. M. Rasouli ◽  
S. Jalalzadeh ◽  
P. V. Moniz
Keyword(s):  
Quantum Mechanics ◽  
Fractional Calculus ◽  
Quantum Cosmology ◽  
Cosmological Solution ◽  
Isotropic Universe ◽  
Fractional Quantum ◽  
Stiff Matter ◽  
Standard Quantum

We start by presenting a brief summary of fractional quantum mechanics, as means to convey a motivation towards fractional quantum cosmology. Subsequently, such application is made concrete with the assistance of a case study. Specifically, we investigate and then discuss a model of stiff matter in a spatially flat homogeneous and isotropic universe. A new quantum cosmological solution, where fractional calculus implications are explicit, is presented and then contrasted with the corresponding standard quantum cosmology setting.

scholarly journals Quantum backflow in solutions to the Dirac equation of the spin-1 2 free particle

2018 ◽  
Vol 33 (32) ◽  
pp. 1850186 ◽  
Author(s):  
Hong-Yi Su ◽  
Jing-Ling Chen
Keyword(s):  
Quantum Mechanics ◽  
Dirac Equation ◽  
Relativistic Particle ◽  
Relativistic Quantum ◽  
Free Particle ◽  
Negative Energy ◽  
Dirac Particle ◽  
Relativistic Quantum Mechanics ◽  
Probability Current ◽  
Negative Probability

It was known that a free, non-relativistic particle in a superposition of positive momenta can, in certain cases, bear a negative probability current — hence termed quantum backflow. Here, it is shown that more variations can be brought about for a free Dirac particle, particularly when negative-energy solutions are taken into account. Since any Dirac particle can be understood as an antiparticle that acts oppositely (and vice versa), quantum backflow is found to arise in the superposition (i) of a well-defined momentum but different signs of energies, or more remarkably (ii) of different signs of both momenta and energies. Neither of these cases has a counterpart in non-relativistic quantum mechanics. A generalization by using the field-theoretic formalism is also presented and discussed.

Collapse models tested in the LNGS underground laboratories

2019 ◽  
Vol 17 (08) ◽  
pp. 1941011
Author(s):  
Catalina Curceanu ◽  
Raffaele Del Grande ◽  
Matthias Laubenstein ◽  
Kristian Piscicchia
Keyword(s):  
Quantum Mechanics ◽  
Measurement Problem ◽  
Photon Emission ◽  
Spontaneous Radiation ◽  
Emission Data ◽  
Standard Quantum ◽  
Wave Function Collapse ◽  
X Ray ◽  
Data Analyses ◽  
Collapse Models

Collapse models consist in dynamical reformulations of the standard quantum mechanics aiming to solve the measurement problem. The standard Schrödinger dynamics is modified with the introduction of nonlinear and stochastic terms, which induce the wave function collapse in space. Collapse models predict slight deviations from the standard quantum mechanics predictions, in particular the emission of a “spontaneous radiation”, which we explored to set the most stringent limits on the collapse models parameters in a broad range. To this end, the X-ray emission data collected by the IGEX collaboration are analyzed and compared with the spectrum of the spontaneous photon emission process predicted by the theories. The results of the data analyses, and the ongoing experimental efforts will be presented.

scholarly journals A Novel Exact Solution of the 2+1-Dimensional Radial Dirac Equation for the Generalized Dirac Oscillator with the Inverse Potentials

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
ZiLong Zhao ◽  
ZhengWen Long ◽  
MengYao Zhang
Keyword(s):  
Exact Solution ◽  
Quantum Mechanics ◽  
Dirac Equation ◽  
Exact Solutions ◽  
Bethe Ansatz ◽  
Dirac Oscillator ◽  
Solvable Models ◽  
Ansatz Method ◽  
Radial Dirac Equation

The generalized Dirac oscillator as one of the exact solvable models in quantum mechanics was introduced in 2+1-dimensional world in this paper. What is more, the general expressions of the exact solutions for these models with the inverse cubic, quartic, quintic, and sixth power potentials in radial Dirac equation were further given by means of the Bethe ansatz method. And finally, the corresponding exact solutions in this paper were further discussed.

scholarly journals An extended Dirac equation in noncommutative spacetime

2016 ◽  
Vol 31 (15) ◽  
pp. 1650089 ◽  
Author(s):  
R. Vilela Mendes
Keyword(s):  
Quantum Mechanics ◽  
Dirac Equation ◽  
Relativistic Quantum ◽  
Large Mass ◽  
Exterior Algebra ◽  
Relativistic Quantum Mechanics ◽  
Spacetime Geometry ◽  
Noncommutative Spacetime ◽  
Extended Dirac Equation

Stabilizing, by deformation, the algebra of relativistic quantum mechanics a noncommutative spacetime geometry is obtained. The exterior algebra of this geometry leads to an extended massless Dirac equation which has both a massless and a large mass solution. The nature of the solutions is discussed as well as the effects of coupling the two solutions.

Actual and general Manning–Rosen potentials under spin and pseudospin symmetries of the Dirac equation

2012 ◽  
Vol 90 (7) ◽  
pp. 633-646 ◽  
Author(s):  
H. Hassanabadi ◽  
E. Maghsoodi ◽  
S. Zarrinkamar ◽  
H. Rahimov
Keyword(s):  
Quantum Mechanics ◽  
Dirac Equation ◽  
Comparative Study ◽  
Analytical Solutions ◽  
Tensor Interaction ◽  
Centrifugal Term ◽  
Supersymmetry Quantum Mechanics

The so-called general and actual Manning–Rosen potentials have been investigated under spin and pseudospin symmetries of the Dirac equation in a comparative study. By approximating the centrifugal term, we have reported the analytical solutions to the problem via supersymmetry quantum mechanics. Illustrative figures and tables are included to discuss the problem in detail. The role of a Coulomb tensor interaction is investigated too. We see that the degenerate doublets are the same in both cases.

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