Free Relativistic Particle Research Articles

Thermal time as an unsharp observable

We show that the Connes–Rovelli thermal time associated with the quantum harmonic oscillator can be described as an (unsharp) observable, that is, as a positive operator valued measure. We furthermore present extensions of this result to the free massless relativistic particle in one dimension and to a hypothetical physical system whose equilibrium state is given by the noncommutative integral.

Quantum geodesics in quantum mechanics

We show that the standard Heisenberg algebra of quantum mechanics admits a noncommutative differential calculus Ω1 depending on the Hamiltonian p2/2m + V(x), and a flat quantum connection ∇ with torsion such that a previous quantum-geometric formulation of flow along autoparallel curves (or “geodesics”) is exactly Schrödinger’s equation. The connection ∇ preserves a non-symmetric quantum metric given by the canonical symplectic structure lifted to a rank (0, 2) tensor on the extended phase space where we adjoin a time variable. We also apply the same approach to obtain a novel flow generated by the Klein–Gordon operator on Minkowski spacetime with a background electromagnetic field, by formulating quantum “geodesics” on the relativistic Heisenberg algebra with proper time for the external geodesic parameter. Examples include quantum geodesics that look like a relativistic free particle wave packet and a hydrogen-like atom.

Gravitoelectric effect in the condensed magnetic sea

AbstractTrapped graviton in magnetic seas induces magnetic fields as a function of time in the additional space. The Soon Joe generator made the Graviton set behave as free relativistic quantum particles. The current and voltage generated when the LED was turned on and off were measured five times. Measurements were made in units of 1/1000 of a second, and the measured data were summed. In the LED off‐state, the average current was −2.87E‐03 (A), and the average voltage was −1.44E‐01 (V) in VH and 6.83E‐01 (V) in VL. The average current in the LED on‐stage was −4.28E‐03, the VH was 2.14E‐01, and the VL was 6.57E‐01. The voltage difference was −8.27E‐01 in the off‐stage and −8.71E‐01 in the on‐stage. Less current was generated in the off‐stage, with less voltage difference. In this experiment, we confirmed that the graviton generates the current, and with the photons, more current is generated. This explains why the interactive induction protocol of gravitons or photons can be used to experiment with the magnetic field's ability to communicate or transfer energy with relativistic quantum particles. The gravitoelectric effect explains the photoelectric effect elements, and graviton has induced electricity as a physical entity in the magnetic sea.

Space-time origin of gauge symmetry

In this work, by a first principles calculation, we show that quantum states describing massive relativistic free spinning particles obey kinematical conditions whose origin can be traced to parity as a good quantum number. These conditions are at the root of the equations of motion and of the constraints satisfied by the corresponding fields. In the massless limit, well defined parity is lost but a symmetry emerges related to arbitrary changes in the unphysical parity components. It is shown that this emergent symmetry is the celebrated gauge symmetry.

Wigner function for polymer particle and Galileo relativity

We put forward a Wigner function of a free non relativistic particle in one spatial dimension within polymer quantization. To do so we use the algebra of the Euclidian group E(2) to which the “flux-holonomy” algebra of the polymer quantization can be reduced. The Wigner function of energy eigenstates fulfills an energy equation that is also introduced. Although not invariant itself the Wigner function combines with other quantity to form an invariant under deformed Galileo boosts with deformation parameter given by the length scale μ of the discrete particle position. Our analysis sheds light on the fate of spacetime symmetries within polymer quantization in line with recent results for relativistic particle. Open problems are commented upon in the discussion.

Relativistic Hydrodynamic Interpretation of de Broglie Matter Waves

We present a classical hydrodynamic analog of free relativistic quantum particles inspired by de Broglie’s pilot wave theory and recent developments in hydrodynamic quantum analogs. The proposed model couples a periodically forced Klein–Gordon equation with a nonrelativistic particle dynamics equation. The coupled equations may represent both quantum particles and classical particles driven by the gradients of locally excited Faraday waves. Exact stationary solutions of the coupled system reveal a highly nonlinear mechanism responsible for the self-propulsion of free particles, leading to the onset of unsteady motion. Although the model is essentially nonrelativistic, a stabilizing mechanism for any particle traveling close to the wave signaling speed emerges through the coupling with the wavefield. Consequently, inline particle oscillations comparable to de Broglie’s wavelength are realized through this fully-classical model, suggesting a new classical interpretation for the motion of relativistic quantum particles.

1D diffeomorphism invariant model of a free scalar relativistic particle: Supervariable and BRST approaches

We apply the supervariable approach to derive the proper quantum Becchi–Rouet–Stora–Tyutin (BRST) and anti-BRST symmetries for the 1D diffeomorphism invariant model of a free scalar relativistic particle by exploiting the infinitesimal classical reparameterization (i.e. 1D diffeomorphism) symmetry of this theory. We derive the conserved and off-shell nilpotent (anti-)BRST charges and prove their absolute anticommutativity property by using the virtues of Curci–Ferrari (CF)-type restriction of our present theory. We establish the sanctity of the existence of CF-type restriction (i) by considering the (anti-)BRST symmetry transformations of the coupled (but equivalent) Lagrangians and (ii) by proving the symmetry invariance of the Lagrangians within the framework of supervariable approach. We capture the nilpotency and absolute anticommutativity of the conserved (anti-)BRST charges within the framework of (anti-)chiral supervariable approach (ACSA) to BRST formalism. One of the novel observations of our present endeavor is the derivation of CF-type restriction by using the modified Bonora–Tonin (BT) supervariable approach (while deriving the (anti-)BRST symmetries for the target space–time and/or momenta variables) and by symmetry considerations of the Lagrangians of the theory. The rest of the (anti-)BRST symmetries, for the other variables, are derived by using the newly proposed ACSA. We also demonstrate the existence of CF-type restriction in the proof of absolute anticommutativity of the (anti-)BRST charges.

Experiment regarding magnetic fields with gravity

This experiment was designed to test the string theory as a physical reality. The ground-based device placed the N poles of the magnets upwards, north, south, east, and west. Coil Ass'Y was placed between 2 N poles with bearing covers on the top and bottom. Gravity interacts to generate electricity in the Earth's direction or the opposite direction by the repulsive magnetic force. The voltage was measured from 3.60 to 3.80 sequentially while the generator was stationary through the monitor. The author found symmetry in Lex Tertia voltage and current zero data during experiment F4 6380 at a balanced state under gravity with the repulsive magnetic force. It generated from 42.8 to 794 μV in the vacuum chamber but from negative 16.1 to positive 18.3 μV in the air. As a result, the author measured more negative current and positive voltage generated in a vacuum. Trapped gravity was set to behave as free relativistic quantum particles or fluids in the magnetic sea. The result made it accessible to study the magnetic sea for different initial superpositions of positive- and negative-gravity spinor states. This might explain the relativistic quantum gravity exists as a physical reality, graviton interacting with photons to induce a magnetic field.

Geometric quantization: Particles, fields and strings

These notes present an introduction to the method of geometric quantization. We discuss the main theorems in a style suitable for a theoretical physicist with an eye towards the physical motivation and the interpretation of the geometric construction as providing a solution to Dirac’s axioms of quantization. We provide in detail the examples of free relativistic particles, their corresponding quantum fields, and the bosonic string using formalism of double field theory. This paper is based on lectures written by Gabriel Cardoso.

Toverline{T} deformations and the width of fundamental particles

We provide a simple geometric meaning for deformations of so-called Toverline{T} type in relativistic and non-relativistic systems. Deformations by the cross products of energy and momentum currents in integrable quantum field theories are known to modify the thermodynamic Bethe ansatz equations by a “CDD factor”. In turn, CDD factors may be interpreted as additional, fixed shifts incurred in scattering processes: a finite width added to the fundamental particles (or, if negative, to the free space between them). We suggest that this physical effect is a universal way of understanding Toverline{T} deformations, both in classical and quantum systems. We first show this in non-relativistic systems, with particle conservation and translation invariance, using the deformation formed out of the densities and currents of particles and momentum. This holds at the level of the equations of motion, and for any interaction potential, integrable or not. We then argue, and show by similar techniques in free relativistic particle systems, that Toverline{T} deformations of relativistic systems produce the equivalent phenomenon, accounting for length contractions. We also show that, in both the relativistic and non-relativistic cases, the width of particles is equivalent to a state-dependent change of metric, where the distance function discounts the particles’ widths, or counts the additional free space. This generalises and explains the known field-dependent coordinate change describing Toverline{T} deformations. The results connect such deformations with generalised hydrodynamics, where the relations between scattering shifts, widths of particles and state-dependent changes of metric have been established.

Evaluation of cross section of elastic scattering for non-relativistic and relativistic particles by means of fundamental scattering formulas

In evaluating differential cross section of elastic scattering, different theories were applied to low-momentum and relativistic particles. For low-momentum motion, Lippmann-Schwinger scattering equation was applied, called fundamental formula; while for relativistic particles, a general scattering theory was used which calculates S matrix. In this paper, Lippmann-Schwinger equation is applied uniformly to both low-momentum and relativistic particles. The cross sections are valuated to the first order of Born approximation. One-body time-independent Green's functions for relativistic free particles are given. Compared to the general scattering theory, the fundamental theory has a clearer physical picture and the approximations made are more explicit.

Reparameterization Invariant Model of a Supersymmetric System: BRST and Supervariable Approaches

We carry out the Becchi-Rouet-Stora-Tyutin (BRST) quantization of the one 0 + 1 -dimensional (1D) model of a free massive spinning relativistic particle (i.e., a supersymmetric system) by exploiting its classical infinitesimal and continuous reparameterization symmetry transformations. We use the modified Bonora-Tonin (BT) supervariable approach (MBTSA) to BRST formalism to obtain the nilpotent (anti-)BRST symmetry transformations of the target space variables and the (anti-)BRST invariant Curci-Ferrari- (CF-) type restriction for the 1D model of our supersymmetric (SUSY) system. The nilpotent (anti-)BRST symmetry transformations for other variables of our model are derived by using the (anti-)chiral supervariable approach (ACSA) to BRST formalism. Within the framework of the latter, we have shown the existence of the CF-type restriction by proving the (i) symmetry invariance of the coupled Lagrangians and (ii) the absolute anticommutativity property of the conserved (anti-)BRST charges. The application of the MBTSA to a physical SUSY system (i.e., a 1D model of a massive spinning particle) is a novel result in our present endeavor. In the application of ACSA, we have considered only the (anti-)chiral super expansions of the supervariables. Hence, the observation of the absolute anticommutativity of the (anti-)BRST charges is a novel result. The CF-type restriction is universal in nature as it turns out to be the same for the SUSY and non-SUSY reparameterization (i.e., 1D diffeomorphism) invariant models of the (non-)relativistic particles.

Path integral of the relativistic point particle in Minkowski space

In this article, we analyze the fundamental global and local symmetries involved in the action for the free relativistic point particle in Minkowski space. Moreover, we identify a hidden local symmetry, whose explicit consideration and factorization utilizing of a Fujikawa prescription leads to the construction of relativistic two-point correlation functions that satisfy the Chapman-Kolmogorov identity. By means of a detailed topological analysis, we find three different relativistic correlation functions (orthochronous, spacelike, and Feynman) which are obtained from the exclusive integration of paths within different sectors in Minkowski space. Finally, the connection of this approach to the Feynman checkerboard construction is explored.

5-Dimensional SO(1,4)-invariant action as an origin to the Magueijo-Smolin Doubly Special Relativity proposal

In this paper we discuss how the Magueijo-Smolin Doubly Special Relativity proposal may be obtained from a singular Lagrangian action. The deformed energy-momentum dispersion relation rises as a particular gauge, whose covariance imposes the non-linear Lorentz group action. Moreover, the additional invariant scale is present from the beginning as a coupling constant to a gauge auxiliary variable. The geometrical meaning of the gauge fixing procedure and its connection to the free relativistic particle are also described.

New results by low momentum approximation from relativistic quantum mechanics equations and suggestion of experiments

A fundamental belief is that the formulism of relativistic quantum mechanics equations (RQMEs) should remain in low momentum motion. However, it is found that some formulas from RQMEs were lost in Schrödinger equation. For example, a free relativistic particle has positive and negative energy branches. The former includes positive kinetic energy (PKE) and the latter negative kinetic energy (NKE). The latter should be treated on an equal footing as the former. Nevertheless, from Schrödinger equation, a free particle can have only PKE. Starting from RQMEs and taking low momentum approximation, we derive NKE Schrödinger equation which is for the cases that free particles have NKE. Thus negative energy branch of RQMEs can be retained in low momentum motion. We point out a fact that whether Schrödinger equation is applicable in a region where a particle’s energy E is less than potential V, E < V, has never been quantitatively verified. In such a region NKE Schrödinger equation should be employed. With the help of NKE Schrödinger equation, the lost formulas are recovered. The so-called difficulty of negative probability of Klein–Gordon equation for free particles is solved. A PKE (NKE) particle can have stationary motion only when it is subject to an attractive (repulsive) potential, which is determined by Virial theorem. Two NKE electrons in a potential can constitute a stable system, a new kind of possible mechanism for electron paring. The whole discussion stems from RQMEs with no any new postulation. Experiments are suggested, which may confirm that there are indeed NKE electrons.

Space-time Schr\xf6dinger symmetries of a post-Galilean particle

We study the space-time symmetries of the actions obtained by expanding the action for a massive free relativistic particle around the Galilean action [1]. We obtain all the point space-time symmetries of the post-Galilean actions by working in canonical space. We also construct an infinite collection of generalized Schrödinger algebras parameterized by an integer M, with M = 0 corresponding to the standard Schrödinger algebra. We discuss the Schrödinger equations associated to these algebras, their solutions and projective phases.

Relativistic treatment of Verlinde’s emergent force in Tsallis’ statistics

Following Chakrabarti, et al. [R. Chakrabarti, R. Chandrashekar and S. S. Naina Mohammed, Physica A 389, 1571 (2010)], we attempt a classical relativistic treatment of Verlinde’s emergent entropic force conjecture by appealing to a relativistic Hamiltonian in the context of Tsalli’s statistics. The ensuing partition function becomes the classical one for small velocities. We show that Tsallis’ relativistic (classical) free particle distribution at temperature T can generate Newton’s gravitational force’s [Formula: see text] distance’s dependence. If we want to repeat the concomitant argument by appealing to Renyi’s distribution, the attempt fails and one needs to modify the conjecture.

(Anti-)chiral supervariable approach to nilpotent and absolutely anticommuting conserved charges of reparametrization invariant theories: A couple of relativistic toy models as examples

We exploit the potential and power of the Becchi–Rouet–Stora–Tyutin (BRST) and anti-BRST invariant restrictions on the (anti-)chiral supervariables to derive the proper nilpotent (anti-)BRST symmetries for the reparametrization invariant one (0[Formula: see text]+[Formula: see text]1)-dimensional (1D) toy models of a free relativistic particle as well as a free spinning (i.e. supersymmetric) relativistic particle within the framework of (anti-)chiral supervariable approach to BRST formalism. Despite the (anti-)chiral super expansions of the (anti-)chiral supervariables, we observe that the (anti-)BRST charges, for the above toy models, turn out to be absolutely anticommuting in nature. This is one of the novel observations of our present endeavor. For this proof, we utilize the beauty and strength of Curci–Ferrari (CF)-type restriction in the context of a spinning relativistic particle but no such restriction is required in the case of a free scalar relativistic particle. We have also captured the nilpotency property of the conserved charges as well as the (anti-)BRST invariance of the appropriate Lagrangian(s) of our present toy models within the framework of (anti-)chiral supervariable approach.

Obtaining the non-relativistic quantum mechanics from quantum field theory: issues, folklores and facts

Given the classical dynamics of a non-relativistic particle in terms of a Hamiltonian or an action, it is relatively straightforward to obtain the non-relativistic quantum mechanics (NRQM) of the system. These standard procedures, based on either the Hamiltonian or the path integral, however, do not work in the case of a relativistic particle. As a result we do not have a single-particle description of relativistic quantum mechanics (RQM). Instead, the correct approach requires a transmutation of dynamical variables from the position and momentum of a single particle to a field and its canonical momentum. Particles, along with antiparticles, reappear in a very nontrivial manner as the excitations of the field. The fact that one needs to adopt completely different languages to describe a relativistic and non-relativistic free particle implies that obtaining the NRQM limit of QFT is conceptually nontrivial. I examine this limit in several approaches (like, for e.g., Hamiltonian dynamics, Lagrangian and Hamiltonian path integrals, field theoretic description etc.) and identify the precise issues which arise when one attempts to obtain the NRQM from QFT in each of these approaches. The dichotomy of NRQM and QFT does not originate just from the square root in the Hamiltonian or from the demand of Lorentz invariance, as is sometimes claimed. The real difficulty has its origin in the necessary existence of antiparticles to ensure a particular notion of relativistic causality. Because of these conceptual issues, it turns out that one cannot, in fact, obtain some of the popular descriptions of NRQM by any sensible limiting procedure applied to QFT. To obtain NRQM from QFT in a seamless manner, it is necessary to work with NRQM expressed in a language closer to that of QFT. This fact has several implications, especially for the operational notion of space coordinates in quantum theory. A close examination of these issues, which arise when quantum theory is combined with special relativity, could offer insights in the context of attempts to combine quantum theory with general relativity.

Superluminal Tunneling of a Relativistic Half-Integer Spin Particle Through a Potential Barrier

This paper investigates the problem of a relativistic Dirac half-integer spin free particle tunneling through a rectangular quantum-mechanical barrier. If the energy difference between the barrier and the particle is positive, and the barrier width is large enough, there is proof that the tunneling may be superluminal. For first spinor components of particle and antiparticle states, the tunneling is always superluminal regardless the barrier width. Conversely, the second spinor components of particle and antiparticle states may be either subluminal or superluminal depending on the barrier width. These results derive from studying the tunneling time in terms of phase time. For the first spinor components of particle and antiparticle states, it is always negative while for the second spinor components of particle and antiparticle states, it is always positive, whatever the height and width of the barrier. In total, the tunneling time always remains positive for particle states while it becomes negative for antiparticle ones. Furthermore, the phase time tends to zero, increasing the potential barrier both for particle and antiparticle states. This agrees with the interpretation of quantum tunneling that the Heisenberg uncertainty principle provides. This study’s results are innovative with respect to those available in the literature. Moreover, they show that the superluminal behaviour of particles occurs in those processes with high-energy confinement.