المؤلفون: Pedro Alberto, Saurya Das, Elias C. Vagenas

المصدر: Repositório Científico de Acesso Aberto de Portugal
Repositório Científico de Acesso Aberto de Portugal (RCAAP)
instacron:RCAAP

مصطلحات موضوعية: High Energy Physics - Theory, Nuclear Theory, General Physics and Astronomy, FOS: Physical sciences, Relativistic quantum mechanics, General Relativity and Quantum Cosmology (gr-qc), Particle in a box, 01 natural sciences, General Relativity and Quantum Cosmology, Relativistic particle, Nuclear Theory (nucl-th), Quantization (physics), symbols.namesake, 0103 physical sciences, Relativistic Particle in a Box, 010306 general physics, Quantum, Klein–Gordon equation, Mathematical physics, Physics, Quantum Physics, 010308 nuclear & particles physics, High Energy Physics - Theory (hep-th), Dirac equation, symbols, Relativistic quantum chemistry, Quantum Physics (quant-ph)

الوصف: The problem of a particle in a box is probably the simplest problem in quantum mechanics which allows for significant insight into the nature of quantum systems and thus is a cornerstone in the teaching of quantum mechanics. In relativistic quantum mechanics this problem allows also to highlight the implications of special relativity for quantum physics, namely the effect that spin has on the quantized energy spectra. To illustrate this point, we solve the problem of a spin zero relativistic particle in a one- and three-dimensional box using the Klein-Gordon equation in the Feshbach-Villars formalism. We compare the solutions and the energy spectra obtained with the corresponding ones from the Dirac equation for a spin one-half relativistic particle. We note the similarities and differences, in particular the spin effects in the relativistic energy spectrum. As expected, the non-relativistic limit is the same for both kinds of particles, since, for a particle in a box, the spin contribution to the energy is a relativistic effect.
Comment: 8 pages, 2 figures, revtex4, to appear in EJP

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::55c7c838ee90542c8c7b1a10e477c455

المؤلفون: Matthew P. G. Robbins, Elias C. Vagenas, Saurya Das

مصطلحات موضوعية: Large class, Physics, High Energy Physics - Theory, Gravity (chemistry), Quantum Physics, Quantum decoherence, 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy and Astrophysics, General Relativity and Quantum Cosmology (gr-qc), 01 natural sciences, General Relativity and Quantum Cosmology, Metric expansion of space, Gravitation, Theoretical physics, High Energy Physics - Theory (hep-th), Space and Planetary Science, 0103 physical sciences, Quantum system, Quantum gravity, 010306 general physics, Quantum Physics (quant-ph), Quantum, Mathematical Physics

الوصف: It is believed that classical behavior emerges in a quantum system due to decoherence. It has also been proposed that gravity can be a source of this decoherence. We examine this in detail by studying a number of quantum systems, including ultra-relativistic and non-relativistic particles, at low and high temperatures in an expanding Universe, and show that this proposal is valid for a large class of quantum systems.
Comment: 7 pages, REVTeX 4, no figures, to appear in IJMPD

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::db3200c167a330c5aff9118f55a08265

المؤلفون: Gaetano Lambiase, Fabio Scardigli, Elias C. Vagenas

المصدر: Physics Letters B, Vol 767, Iss C, Pp 242-246 (2017)
Physics Letters B

مصطلحات موضوعية: High Energy Physics - Theory, Nuclear and High Energy Physics, Uncertainty principle, General relativity, FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), Deformation (meteorology), 01 natural sciences, General Relativity and Quantum Cosmology, Gravitation, QFT, 0103 physical sciences, Thermal, 010306 general physics, Quantum, Physics, Quantum Physics, Generalized uncertainty principle: quantum gravity, Newtonian potential, 010308 nuclear & particles physics, Spectrum (functional analysis), lcsh:QC1-999, Classical mechanics, High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph), lcsh:Physics

الوصف: We propose a technique to compute the deformation parameter of the generalized uncertainty principle by using the leading quantum corrections to the Newtonian potential. We just assume General Relativity as theory of Gravitation, and the thermal nature of the GUP corrections to the Hawking spectrum. With these minimal assumptions our calculation gives, to first order, a specific numerical result. The physical meaning of this value is discussed, and compared with the previously obtained bounds on the generalized uncertainty principle deformation parameter.
Comment: v1: 6 pages, no figures; v2: minor corrections, physics unchanged, to appear in Phys. Lett. B. arXiv admin note: text overlap with arXiv:1407.0113

وصف الملف: application/pdf

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e5011e6913199bc52efb5ee7aeebbcb3

المؤلفون: Ali, Ahmed Farag, Khalil, Mohammed M., Vagenas, Elias C.

مصطلحات موضوعية: High Energy Physics - Theory, General Relativity and Quantum Cosmology, High Energy Physics - Phenomenology, Quantum Physics, High Energy Physics - Phenomenology (hep-ph), High Energy Physics - Theory (hep-th), FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), Quantum Physics (quant-ph)

الوصف: The existence of a minimal length is a common prediction of various theories of quantum gravity. This minimal length leads to a modification of the Heisenberg uncertainty principle to a Generalized Uncertainty Principle (GUP). Various studies showed that a GUP modifies the Hawking radiation of black holes. In this paper, we propose a modification of the Schwarzschild metric based on the modified Hawking temperature derived from the GUP. Based on this modified metric, we calculate corrections to the deflection of light, time delay of light, perihelion precession, and gravitational redshift. We compare our results with gravitational measurements to set an upper bound on the GUP parameter.
v1: 7 pages, LaTeX, no figure, to appear in EPL; v2: typos corrected, a comment was made and a reference was added

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::bf191f197cd13b119f05bfb9adf22d30
http://arxiv.org/abs/1510.06365

المؤلفون: Saurya Das, Elias C. Vagenas, Venkat Balasubramanian

مصطلحات موضوعية: Physics, High Energy Physics - Theory, Quantum Physics, Uncertainty principle, 010308 nuclear & particles physics, FOS: Physical sciences, General Physics and Astronomy, General Relativity and Quantum Cosmology (gr-qc), Particle in a box, Mathematics::Spectral Theory, 01 natural sciences, General Relativity and Quantum Cosmology, Algebra, symbols.namesake, High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), High Energy Physics - Theory (hep-th), 0103 physical sciences, symbols, Boundary value problem, Quantum Physics (quant-ph), 010306 general physics, Hamiltonian (quantum mechanics), Self-adjoint operator

الوصف: In this work we explore the self-adjointness of the GUP-modified momentum and Hamiltonian operators over different domains. In particular, we utilize the theorem by von-Newmann for symmetric operators in order to determine whether the momentum and Hamiltonian operators are self-adjoint or not, or they have self-adjoint extensions over the given domain. In addition, a simple example of the Hamiltonian operator describing a particle in a box is given. The solutions of the boundary conditions that describe the self-adjoint extensions of the specific Hamiltonian operator are obtained.
v1: 22 pages, LaTeX, revtex4; v2: 19 pages, minor corrections, to appear in Annals of Physics

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::c9b682583373d5c378b5f1e728f66b97
http://arxiv.org/abs/1404.3962

المؤلفون: Elias C. Vagenas, Saurya Das, Ahmed Farag Ali

المصدر: Physics Letters B. 678(5):497-499

مصطلحات موضوعية: High Energy Physics - Theory, Physics, Quantum Physics, Nuclear and High Energy Physics, Uncertainty principle, Spacetime, 010308 nuclear & particles physics, FOS: Physical sciences, Observable, General Relativity and Quantum Cosmology (gr-qc), 16. Peace & justice, String theory, 01 natural sciences, General Relativity and Quantum Cosmology, Classical mechanics, High Energy Physics - Theory (hep-th), Doubly special relativity, 0103 physical sciences, Quantum gravity, Quantum Physics (quant-ph), 010306 general physics, Virtual black hole, Planck length

الوصف: Various approaches to Quantum Gravity (such as String Theory and Doubly Special Relativity), as well as black hole physics predict a minimum measurable length, or a maximum observable momentum, and related modifications of the Heisenberg Uncertainty Principle to a so-called Generalized Uncertainty Principle (GUP). We propose a GUP consistent with String Theory, Doubly Special Relativity and black hole physics, and show that this modifies all quantum mechanical Hamiltonians. When applied to an elementary particle, it implies that the space which confines it must be quantized. This suggests that space itself is discrete, and that all measurable lengths are quantized in units of a fundamental length (which can be the Planck length). On the one hand, this signals the breakdown of the spacetime continuum picture near that scale, and on the other hand, it can predict an upper bound on the quantum gravity parameter in the GUP, from current observations. Furthermore, such fundamental discreteness of space may have observable consequences at length scales much larger than the Planck scale.
Comment: 3 pages, revtex4, no figures, to appear in Phys. Lett. B

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0285ff5d0b8529f9afb1afde85e9f05f

المؤلفون: Elias C. Vagenas, Bibhas Ranjan Majhi

مصطلحات موضوعية: Physics, High Energy Physics - Theory, Nuclear and High Energy Physics, Quantum Physics, Superluminal motion, Photon, Uncertainty principle, FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), General Relativity and Quantum Cosmology, Unruh effect, High Energy Physics - Theory (hep-th), Quantum electrodynamics, Quantum mechanics, Dispersion relation, Emission spectrum, Quantum Physics (quant-ph), Energy (signal processing)

الوصف: Motivated by the recently derived new form of generalized uncertainty principle we obtain the corresponding dispersion relation which is now modified. This modification can be interpreted as a possible mechanism that makes particles more massive. In addition, the modified velocity of photons is obtained and indicates that photons' propagation depends on their energy, thus superluminal photons are permitted due to generalized uncertainty principle. Furthermore, we derive and solve the two-dimensional Klein-Gordon equation in the presence of GUP corrections, and therefore the GUP-corrected emission spectrum due to the Unruh effect is obtained.
Comment: v1: 11 pages, LaTeX, no figures; v2: a typo corrected and references added to match published version in Phys. Lett. B

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5905d13319b05c506d14508ec8e7c69f

المؤلفون: Ahmed Farag Ali, Saurya Das, Elias C. Vagenas

المصدر: The Twelfth Marcel Grossmann Meeting.

مصطلحات موضوعية: High Energy Physics - Theory, Physics, Quantum Physics, Uncertainty principle, 010308 nuclear & particles physics, FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), 16. Peace & justice, 01 natural sciences, General Relativity and Quantum Cosmology, High Energy Physics - Phenomenology, Theoretical physics, High Energy Physics - Phenomenology (hep-ph), Low energy, Quadratic equation, High Energy Physics - Theory (hep-th), 0103 physical sciences, Quantum gravity, Quantum Physics (quant-ph), 010306 general physics, Phenomenology (particle physics)

الوصف: In this article we examine a Generalized Uncertainty Principle which differs from the Heisenberg Uncertainty Principle by terms linear and quadratic in particle momenta, as proposed by the authors in an earlier paper. We show that this affects all Hamiltonians, and in particular those which describe low energy experiments. We discuss possible observational consequences. Further, we also show that this indicates that space may be discrete at the fundamental level.
3 pages. Talk given by SD at the 12th Marcel Grossmann conference (Paris, July, 2009)

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::190ed8fc060e92ff2bddd3b970bfc38f
https://doi.org/10.1142/9789814374552_0492

المؤلفون: Elias C. Vagenas, Saurya Das, Ahmed Farag Ali

مصطلحات موضوعية: Physics, High Energy Physics - Theory, Nuclear and High Energy Physics, Quantum geometry, Quantum Physics, Hořava–Lifshitz gravity, Spin foam, FOS: Physical sciences, Loop quantum gravity, General Relativity and Quantum Cosmology (gr-qc), String (physics), General Relativity and Quantum Cosmology, Open quantum system, High Energy Physics - Theory (hep-th), Doubly special relativity, Quantum mechanics, Quantum gravity, Quantum Physics (quant-ph)

الوصف: Attempts to formulate a quantum theory of gravitation are collectively known as {\it quantum gravity}. Various approaches to quantum gravity such as string theory and loop quantum gravity, as well as black hole physics and doubly special relativity theories predict a minimum measurable length, or a maximum observable momentum, and related modifications of the Heisenberg Uncertainty Principle to a so-called generalized uncertainty principle (GUP). We have proposed a GUP consistent with string theory, black hole physics and doubly special relativity theories and have showed that this modifies all quantum mechanical Hamiltonians. When applied to an elementary particle, it suggests that the space that confines it must be quantized, and in fact that all measurable lengths are quantized in units of a fundamental length (which can be the Planck length). On the one hand, this may signal the breakdown of the spacetime continuum picture near that scale, and on the other hand, it can predict an upper bound on the quantum gravity parameter in the GUP, from current observations. Furthermore, such fundamental discreteness of space may have observable consequences at length scales much larger than the Planck scale. Because this influences all the quantum Hamiltonians in an universal way, it predicts quantum gravity corrections to various quantum phenomena. Therefore, in the present work we compute these corrections to the Lamb shift, simple harmonic oscillator, Landau levels, and the tunneling current in a scanning tunneling microscope.
v1: 10 pages, REVTeX 4, no figures; v2: minor typos corrected and a reference added. arXiv admin note: has substantial overlap with arXiv:0906.5396 , published in a different journal

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5fdeb585805adf72a21d386a65948630
http://arxiv.org/abs/1107.3164

المؤلفون: Pedro Alberto, Saurya Das, Elias C. Vagenas

المصدر: Repositório Científico de Acesso Aberto de Portugal
Repositório Científico de Acesso Aberto de Portugal (RCAAP)
instacron:RCAAP

مصطلحات موضوعية: High Energy Physics - Theory, Helical Dirac fermion, Atomic Physics (physics.atom-ph), Astrophysics::High Energy Astrophysical Phenomena, Dirac (software), Nuclear Theory, General Physics and Astronomy, FOS: Physical sciences, Energy–momentum relation, General Relativity and Quantum Cosmology (gr-qc), 01 natural sciences, Center of mass (relativistic), General Relativity and Quantum Cosmology, Physics - Atomic Physics, Relativistic particle, symbols.namesake, 0103 physical sciences, 010306 general physics, Dirac sea, Mathematical physics, Physics, Quantum Physics, 010308 nuclear & particles physics, High Energy Physics - Theory (hep-th), Quantum Gases (cond-mat.quant-gas), Quantum electrodynamics, Dirac equation, Relativistic Quantum Mechanics, symbols, Condensed Matter - Quantum Gases, Relativistic quantum chemistry, Quantum Physics (quant-ph)

الوصف: We generalize the work of Alberto, Fiolhais and Gil and solve the problem of a Dirac particle confined in a 3-dimensional box. The non-relativistic and ultra-relativistic limits are considered and it is shown that the size of the box determines how relativistic the low-lying states are. The consequences for the density of states of a relativistic fermion gas are briefly discussed.
Comment: v1: 8 pages, 2 figures, revtex4; v2: minor typos corrected to match published version in Phys. Lett. A

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f92e2ad1449917f5aa655b7d78a55d72