Simple quantum mechanics and complicated ultrasonic attenuation

In physics, experiments ultimately inform us about what constitutes a good theoretical model of any physical concept: physical space should be no exception. The best picture of physical space in Newtonian physics is given by the configuration space of a free particle (or the center of mass of a closed system of particles). This configuration space (as well as phase space) can be constructed as a representation space for the relativity symmetry. From the corresponding quantum symmetry, we illustrate the construction of a quantum configuration space, similar to that of quantum phase space, and recover the classical picture as an approximation through a contraction of the (relativity) symmetry and its representations. The quantum Hilbert space reduces into a sum of one-dimensional representations for the observable algebra, with the only admissible states given by coherent states and position eigenstates for the phase and configuration space pictures, respectively. This analysis, founded firmly on known physics, provides a quantum picture of physical space beyond that of a finite-dimensional manifold and provides a crucial first link for any theoretical model of quantum space-time at levels beyond simple quantum mechanics. It also suggests looking at quantum physics from a different perspective.

Download Full-text

A simple quantum generator of random numbers

Emergent Scientist ◽

10.1051/emsci/2017009 ◽

2017 ◽

Vol 1 ◽

pp. 7

Author(s):

Hugo Roussille ◽

Lionel Djadaojee ◽

Frédéric Chevy

Keyword(s):

Quantum Mechanics ◽

Quantum Measurement ◽

Random Number ◽

Random Number Generator ◽

Random Numbers ◽

Number Generator ◽

Random Generator ◽

Simple Quantum ◽

Quantum Generator ◽

Random Generators

Cryptography techniques rely on chains of random numbers used to generate safe encryption keys. Since random number generator algorithms are in fact pseudo-random their behavior can be predicted if the generation method is known and as such they cannot be used for perfectly safe communications. In this article, we present a perfectly random generator based on quantum measurement processes. The main advantage of such a generator is that using quantum mechanics, its behavior cannot be predicted in any way. We verify the randomness of our generator and compare it to commonly used pseudo-random generators.

Download Full-text

Decoding the wave particle duality

Physics Essays ◽

10.4006/0836-1398-34.3.410 ◽

2021 ◽

Vol 34 (3) ◽

pp. 410-413

Author(s):

Carlos López

Keyword(s):

Quantum Mechanics ◽

Quantum Measurements ◽

Spatial Distance ◽

Evolution Law ◽

Quantum Time ◽

De Broglie Wave ◽

Simple Quantum ◽

Wave Particle Duality ◽

Apparent Violation ◽

New System

The action reaction principle (ARP), a fundamental ingredient of Physics, is taken for granted, because it is automatically fulfilled along the ordinary Hamiltonian, classical or quantum, time evolution law. But in quantum mechanics, there is an extraordinary evolution law, the projection of state rule along quantum measurements, which is not Hamiltonian. Consequently, the ARP is not automatically fulfilled along quantum measurements, and it must be checked case by case. Surprisingly, very simple quantum measurements, both theoretical processes and experiments, show an apparent violation of the ARP, so that the hidden reaction must be found. In the analyzed experiment, the ARP is restored if some new system, the quantum or de Broglie wave, exists and locally interacts with the detector. There cannot be interaction at a spatial distance between the particle (photon or electron) and the obstacle‐detector.

Download Full-text

Position in Minimal Length Quantum Mechanics

Universe ◽

10.3390/universe8010017 ◽

2021 ◽

Vol 8 (1) ◽

pp. 17

Author(s):

Pasquale Bosso

Keyword(s):

Quantum Mechanics ◽

Quantum Gravity ◽

Uncertainty Principle ◽

Generalized Uncertainty Principle ◽

Minimal Length ◽

Standard Theory ◽

Heisenberg Uncertainty Principle ◽

Simple Quantum ◽

Heisenberg Uncertainty ◽

Quantum Mechanical Systems

Several approaches to quantum gravity imply the presence of a minimal measurable length at high energies. This is in tension with the Heisenberg Uncertainty Principle. Such a contrast is then considered in phenomenological approaches to quantum gravity by introducing a minimal length in quantum mechanics via the Generalized Uncertainty Principle. Several features of the standard theory are affected by such a modification. For example, position eigenstates are no longer included in models of quantum mechanics with a minimal length. Furthermore, while the momentum-space description can still be realized in a relatively straightforward way, the (quasi-)position representation acquires numerous issues. Here, we will review such issues, clarifying aspects regarding models with a minimal length. Finally, we will consider the effects of such models on simple quantum mechanical systems.

Download Full-text