Momentum Uncertainty Research Articles

Schrdinger equation for various quantum systems based on Heisenberg's uncertainty principle

This article establishes the proof of the Schrdinger equation for numerous quantum systems, utilizing Heisenberg's uncertainty principle. The Fourier transform connects functions in the time and frequency domains, resulting in the mathematical inequality that is the foundation of the uncertainty principle. In the part of Methods and Theory, the article derives the uncertainty principle through Fourier transforms by defining the mean and variance of angular frequency and time, and subsequently expanding the integral. This establishes the fundamental connection between time and frequency domains, illustrating the constraints imposed by quantum mechanics. In the part of Results and Application, the article applies the uncertainty principle to derive the Schrdinger equation under different conditions: free particle, particle in a box, harmonic oscillator, and hydrogen atom. For each case, the article assumes wave function solutions, uses the uncertainty in position and momentum to estimate kinetic and potential energies, and shows that the total energy matches the ground state energy derived from the Schrdinger equation. The results highlight the critical role of Heisenberg's uncertainty principle in understanding key aspects of quantum mechanics, providing a unified framework for these diverse systems.

Uncertainty of Helium Ion Momentum (𝑯𝒆+) by Using the Heisenberg Uncertainty Approach on Quantum Numbers 𝒏 ≤ 𝟑

Uncertainty of Helium Ion Momentum (𝑯𝒆+) by Using the Heisenberg Uncertainty Approach on Quantum Numbers 𝒏 ≤ 𝟑

Extended uncertainty principle: A deeper insight into the Hubble tension?

The standard cosmological model, known as the ΛCDM model, has been successful in many respects, but it has some significant discrepancies, some of which have not been resolved yet. In measuring the Hubble-Lemaître parameter, there is an apparent discrepancy which is known as the Hubble tension, defined as differences in values of this parameter measured by the Type Ia Supernovae (SNeIa) data (a model-independent method) and by the Cosmic Microwave Background (CMB) radiation maps (a model-dependent method). Although many potential solutions have been proposed, the issue still remains unresolved. Recently, it was observed that the Hubble tension can be due to the concept of uncertainty in measuring cosmological parameters at large distance scales through applying the Heisenberg Uncertainty Principle (HUP) in cosmological setups. Extending this pioneering idea, in the present study we plan to incorporate the Extended Uncertainty Principle (EUP) containing a minimal fundamental measurable momentum (or equivalently, a maximal fundamental measurable length) as a candidate setup for describing large-scale effects of Quantum Gravity (QG) to address the Hubble tension and constrain the EUP length scale. In this regard, by finding a relevant formula for the effective photon rest mass in terms of the present-time value of the Hubble-Lemaître parameter, we see that discrepancies in the value of photon rest mass associated with the Hubble-Lemaître parameter values estimated from model-independent and model-dependent methods perhaps is the cause of Hubble tension. We show explicitly that the presence of a non-zero minimal uncertainty in momentum (or non-zero maximal uncertainty in position) measurements as a consequence of the large distance quantum gravity effect addresses the Hubble tension satisfactorily without having to invoke new physics. Moreover, we use the formula for the effective photon rest mass to find some relevant lower bounds on the EUP length scale.

Study of Bose–Einstein condensate in the presence of the extended uncertainty principle: infinite potential well

This paper investigates the influence of the extended uncertainty principle (EUP) and non-linearity on Bose–Einstein condensate (BEC) confined within an infinite potential well, described by a deformed one-dimensional Gross–Pitaevskii equation (GPE). Exact solutions are derived, and the impact of the EUP and the parameter of interaction g is explored through solution, position, and momentum uncertainties plots. The study reveals significant changes in the probability density and energy spectra, depending on the deformation and non-linearity parameters.

Information entropies with Varshni-Hellmann potential in higher dimensions

This work investigates the behavior of Shannon entropy and Fisher information for the Varshni-Hellmann potential (VHP) in one and three dimensions using the Nikiforov-Uvarov method. We employ the Greene-Aldrich approximation scheme to obtain the energy eigenvalues and normalized wavefunctions, which are then used to calculate these information-theoretic quantities. Our analysis revealed remarkably similar high-order features in both position and momentum spaces. Notably, our calculations showed enhanced accuracy in predicting particle localization within position space. Furthermore, the combined position and momentum entropies obeyed the lower and upper bounds established by the Berkner-Bialynicki-Birula-Mycieslki inequality. Additionally, for three-dimensional systems, the Stam-Cramer-Rao inequalities were fulfilled for different eigenstates with respect to the calculated Fisher information. It is observed that as the position Fisher entropy decreases, indicating a more precise measurement of position, the momentum Fisher entropy must increase. This implies that the Fisher information regarding momentum decreases, resulting in a decrease in the precision of momentum measurement. This demonstrates how position and momentum uncertainties complement each other in quantum mechanics. Exploring the balance between position and momentum Fisher entropy reveals a fundamental aspect of the uncertainty principle in quantum mechanics, highlighting the restrictions on measuring certain pairs of conjugate variables simultaneously with high precision.

Resonant detectors of gravitational wave in the linear and quadratic generalized uncertainty principle framework

In this work, we consider a resonant bar detector of gravitational waves in the generalized uncertainty principle (GUP) framework with linear and quadratic momentum uncertainties. The phonon modes in these detectors vibrate due to the interaction with the incoming gravitational wave. In this uncertainty principle framework, we calculate the resonant frequencies and transition rates induced by the incoming gravitational waves on these detectors. We observe that the energy eigenstates and the eigenvalues get modified by the GUP parameters. We also observe non-vanishing transition probabilities between two adjacent energy levels due to the existence of the linear order momentum correction in the generalized uncertainty relation which was not present in the quadratic GUP analysis (Class Quantum Gravity 37:195006, 2020). We finally obtain bounds on the dimensionless GUP parameters using the form of the transition rates obtained during this analysis.

One dimensional Bose–Einstein condensate under the effect of the extended uncertainty principle

In this study, an analytical investigation was conducted to assess the effects of the extended uncertainty principle (EUP) on a Bose–Einstein condensate (BEC) described by the deformed one-dimensional Gross–Pitaevskii equation (GPE). Analytical solutions were derived for null potential while we used variational and numerical methods for a harmonic oscillator potential. The effects of EUP on stability, probability density, position, and momentum uncertainties of BEC are analyzed. The EUP is found to be applicable for the free dark soliton solution and in the presence of a harmonic potential within specific ranges of the deformation parameter α, while it is not valid for the free bright soliton solution.

The momentum ambiguity and investor trading behavior

This paper investigates the impact of momentum ambiguity on investor trading behavior. Specifically, our findings suggest that in the presence of momentum (reversal) effects in asset returns, investors’ demand for the risky asset comprises myopic, hedging, and speculative components. Due to the opposite signs of hedging and speculative demands, the relationship between total demand and momentum effects may display a non-monotonic trend. The introduction of momentum uncertainty leads investors to adopt a more conservative approach, and in some cases, abstain from trading the risky asset altogether. Additionally, we observe heterogeneity in the impact of momentum and reversal uncertainty levels on investor demand.

Geometric uncertainty in non-paraxial interference

In this article, a novel meaning for the notion of uncertainty is discussed, within the framework of the non-paraxial interference theory based on confinement in geometric states of space. This novel meaning refers to the fact that, for any set of space states whose vertices are distributed in an arbitrary array of size less than λ 10, both the excitation provided by the geometric potential and the positions of the vertices of the states are completely uncertain, such that the complete set is represented by the Lorentzian well of an individual ground state of space, with vertex at any of the points of the array, even if the set is under the maximum prepared non-locality (i.e., under a strong geometric potential). It is shown that the geometric uncertainty is different but compatible with the Heisenberg uncertainty principle. In fact, geometrical uncertainty establishes both the upper limit of momentum uncertainty and the lower limit of position uncertainty in the Heisenberg principle.

Speeding up the GENGA N-body integrator on consumer-grade graphics cards

Context. Graphics processing unit (GPU) computing has become popular due to the enormous calculation potential that can be harvested from a single card. The N-body integrator Gravitational ENcounters with GPU Acceleration (GENGA) is built to harvest the computing power from such cards, but it suffers a severe performance penalty on consumer-grade Nvidia GPUs due to their artificially truncated double precision performance. Aims. We aim to speed up GENGA on consumer-grade cards by harvesting their high single-precision performance. Methods. We modified GENGA to have the option to compute the mutual long-distance forces between bodies in single precision and tested this with five experiments. First, we ran a high number of simulations with similar initial conditions of on average 6600 fully self-gravitating planetesimals in both single and double precision to establish whether the outcomes were statistically different. These simulations were run on Tesla K20 cards. We supplemented this test with simulations that (i) began with a mixture of planetesimals and planetary embryos, (ii) planetesimal-driven giant planet migration, and (iii) terrestrial planet formation with a dissipating gas disc. All of these simulations served to determine the accuracy of energy and angular momentum conservation under various scenarios with single and double precision forces. Second, we ran the same simulation beginning with 40 000 self-gravitating planetesimals using both single and double precision forces on a variety of consumer-grade and Tesla GPUs to measure the performance boost of computing the long-range forces in single precision. Results. We find that there are no statistical differences when simulations are run with the gravitational forces in single or double precision that can be attributed to the force prescription rather than stochastic effects. The accumulations in uncertainty in energy are almost identical when running with single or double precision long-range forces. However, the uncertainty in the angular momentum using single rather than double precision long-range forces is about two orders of magnitude greater, but still very low. Running the simulations in single precision on consumer-grade cards decreases running time by a factor of three and becomes within a factor of three of a Tesla A100 GPU. Additional tuning speeds up the simulation by a factor of two across all types of cards. Conclusions. The option to compute the long-range forces in single precision in GENGA when using consumer-grade GPUs dramatically improves performance at a little penalty to accuracy. There is an additional environmental benefit because it reduces energy usage.

Classical Limit and Ehrenfest’s Theorem Versus Non-relativistic Limit of Noncommutative Dirac Equation in the Presence of Minimal Uncertainty in Momentum

Classical Limit and Ehrenfest’s Theorem Versus Non-relativistic Limit of Noncommutative Dirac Equation in the Presence of Minimal Uncertainty in Momentum

Path integral in position-deformed Heisenberg algebra with maximal length uncertainty

In this work, we study the path integral in a position-deformed Heisenberg algebra with quadratic deformation which implements both minimal momentum and maximal length uncertainties. We construct propagators of path integrals within this deformed algebra using the position space representation on the one hand and the Fourier transform and its inverse representations on the other. The result is remarkably similar to the one obtained by Pramanik (2022) from the Perivolaropoulos’s deformed algebra (Perivolaropoulos, 2017). Then, the propagators and the corresponding actions of a free particle and a simple harmonic oscillator are discussed as examples. We also show that the actions which describe the classical trajectories of both systems are bounded by the ordinary ones of classical mechanics due to the existence of this maximal length. Consequently, particles of these systems travel faster from one point to another with low kinetic and mechanical energies.

Harmonic oscillator in the context of the extended uncertainty principle

At large-scale distances where the space-time is curved due to gravity, a nonzero minimal uncertainty in the momentum, [Formula: see text], is being estimated to emerge. The presence of minimal uncertainty in momentum allows a modification to the quantum uncertainty principle, which is known as the extended uncertainty principle (EUP). In this work, we handle the harmonic oscillator problem in the EUP scenario and obtain analytical exact solutions in classical and semi-classical domains. In the classical context, we establish the equations of motion of the oscillator and show that the EUP-corrected frequency is depending on the energy and deformation parameter. In the semi-classical domain, we derive the energy eigenvalue levels and demonstrate that the energy spectrum depends on [Formula: see text], as the feature of hard confinement. Finally, we investigate the impact of the EUP on the harmonic oscillator’s thermodynamic properties by using the EUP-corrected partition functions in the classical limit in the (A)dS backgrounds.

Effects of coupling with a quantum oscillator on time-evolution of uncertainties of a quantum particle and entanglement entropy

The time evolution of a quantum particle’s product of uncertainties in position and momentum is calculated when it is coupled with an external source. We have used a simple toy model where the particle is subject to a harmonic potential and coupled with an equivalent harmonic oscillator via a linear term. It is found that the long-time-averaged product is an increasing function of the coupling strength. It diverges when one of the eigenmodes of the coupled system goes soft, with the singular term twice of that for the stationary state. Generally, there is a jump of finite size for this quantity when a small coupling is turned on, compared to the uncoupled case. Similar behaviors have also been found for the von Neumann entanglement entropy, which is calculated exactly using a covariance matrix formalism. We find that the mode-interference plays an important role in the main features of this work.

Relative distance of entangled systems in emergent spacetime scenarios

Spacetime emergence from entanglement proposes an alternative to quantizing gravity and typically derives a notion of distance based on the amount of mutual information shared across subsystems. Albeit promising, this program still faces challenges to describe simple physical systems, such as a maximally entangled Bell pair that is taken apart while preserving its entanglement. We propose a solution to this problem: a reminder that quantum systems can have multiple sectors of independent degrees of freedom, and that each sector can be entangled. Thus, while one sector can decohere, and decrease the amount of total mutual information within the system, another sector, e.g. spin, can remain entangled. We illustrate this with a toy model, showing that only within the particles' momentum uncertainty there can be considerably more entanglement than in the spin sector for a single Bell pair. We finish by introducing some considerations about how spacetime could be tested in the lab in the future.

Quantum information entropy of heavy mesons in the presence of a point-like defect

Using Schrödinger’s formalism, we investigate the quantum eigenstates of the heavy mesons trapped by a point-like defect and by Cornell’s potential. One implements this defect to the model considering a spherical metric profile coupled to it. Furthermore, the Nikiforov–Uvarov method is applied to theory to study the quantum eigenstates of the heavy mesons. To calculate the quantum information entropy (QIE), one considers the wave functions that describe the charmonium and bottomonium states. To explore the QIE, we use the well-known Shannon’s entropy formulated at the position and reciprocal space. The analysis of the QIE gives us relevant information about how the quantum information change with the variation of the point-like defect. Consequently, considering the Bialynicki-Birula and Mycielski (BBM) relation, we show how this defect influences the quarkonium position and momentum uncertainty measures.

The effect of in-doping on the quantum information entropy of hydrogenic impurity states in the InxGa1-xN semiconductor quantum dot

ABSTRACT The effect of In-doping on the quantum information entropy of the hydrogenic impurity states in the InxGa1-xN quantum dot has been studied for the first time. By exploring the Shannon entropy in the position space (Sr ), in the momentum-space (Sp ) and the Shannon entropy sum St , we find some novel and interesting phenomenon. First, although Sr increases and Sp decreases monotonically with the radius of InxGa1-xN quantum dot, the Shannon entropy sum St exhibits a series of peaks and valleys with the confinement radius. The physical origin of the minimum and maximum values in the Shannon entropy sum St is analysed in great detail. Second, the BBM entropy uncertainty principle () holds for the hydrogenic impurity state in the semiconductor quantum dot, which can be used to replace the Heisenberg uncertainty principle in the quantum mechanics. Third, the content of the doping In element in the InxGa1-xN quantum dot has a great influence on the Shannon entropy of the hydrogenic impurity state. Since the Shannon entropy sum St is usually used to measure the position-momentum correlation, therefore, we can explore the uncertainty of position and momentum of the hydrogenic impurity states by changing the content of the doping element in the semiconductor quantum dots. This study has some practical applications in semiconductor material and quantum information measurement, and may guide future experimental researches for the localisation and delocalisation characteristics of hydrogenic impurities states in the semiconductor quantum dots.

Foldy–Wouthuysen Transformation of Noncommutative Dirac Equation in the Presence of Minimal Uncertainty in Momentum

Foldy–Wouthuysen Transformation of Noncommutative Dirac Equation in the Presence of Minimal Uncertainty in Momentum

Exploring the implications of the uncertainty relationships in quantum mechanics

Heisenberg guessed, after he established the matrix quantum mechanics, that the non-commutativity of the matrices of position and momentum implied that the position and momentum of a particle could not be precisely simultaneously determined. He consequently conjectured that time and energy should also have a similar relationship. Soon after, Robertson derived an inequality concerning the space coordinate and momentum, which was thought to be the mathematical expression of the uncertainty relation guessed by Heisenberg. Since then, people have tried various devices to prove the correctness of these two relations. However, no one conducted a careful analysis of Heisenberg’s primary paper. In this work, we point out some serious problems in Heisenberg’s paper and the literature talking about the uncertainty relationships: the physical concepts involved in the uncertainty relations are not clear; one physical concept had more than one explanation, i.e., switching concepts; there has never been measurement experiment to support the relations. The conclusions are that the so-called coordinate–momentum uncertainty relation has never been related to actual measurement and there does not exist a time–energy uncertainty relation.

Scattering of a twisted electron wavepacket by a finite laser pulse

The behavior of a twisted electron colliding with a linearly polarized laser pulse is investigated within relativistic quantum mechanics. In order to better fit the real experimental conditions, we introduce a Gaussian spatial profile for the initial electron state as well as an envelope function for the laser pulse, so the both interacting objects have a finite size along the laser propagation direction. For this setup we analyze the dynamics of various observable quantities regarding the electron state: the probability density, angular momentum, and mean values of the spatial coordinates. It is shown that the motion of a twisted wavepacket can be accurately described by averaging over classical trajectories with various directions of the transverse momentum component. On the other hand, full quantum simulations demonstrate that the ring structure of the wavepacket in the transverse plane can be significantly distorted leading to large uncertainties in the total angular momentum of the electron. This effect remains after the interaction once the laser pulse has a nonzero electric-field area.