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Basil Altaie | Yarmouk University - Academia.edu

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Basil Altaie

Yarmouk University, Physics Department, Faculty Member

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Homi Bhabha National Institute (HBNI, BARC, MUMBAI)

Georgetown University

University of Illinois at Urbana-Champaign

University of Oxford

University of Bucharest

Joas Wagemakers

Utrecht University

Jonathan D Maltz

Stanford University

Sergey A Khaibrakhmanov

Saint-Petersburg State University

University of York

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Papers by Basil Altaie

Time and Quantum Clocks: A Review of Recent Developments

Frontiers in Physics

In this review we present the problem of time in quantum physics, including a short history of th... more In this review we present the problem of time in quantum physics, including a short history of the problem and the known objections about considering time as a quantum observable. The need to deal with time as an observable is elaborated through some unresolved problems. The lack of a consistent theory of time is currently hindering the formulation of a full-fledged theory of quantum gravity. It is argued that the proposal set forth by several authors of considering an intrinsic measurement of quantum time, besides having the conventional external time, is compelling. Recently several suggestions have been put forward to revive the proposal of Page and Wootters (1983), elaborating and resolving some of the main ambiguities of the original proposal and opening new scope for understanding its content. The approach followed in these new contributions exposes the need to go beyond the limitations enforced by the conventional approach of quantum physics. The attitude of covariant loop qu...

An intuitive picture of the Casimir effect

The Casimir effect, which predicts the emergence of an attractive force between two parallel, hig... more The Casimir effect, which predicts the emergence of an attractive force between two parallel, highly reflecting plates in vacuum, plays a vital role in various fields of physics, from quantum field theory and cosmology to nanophotonics and condensed matter physics. Nevertheless, Casimir forces still lack an intuitive explanation and current derivations rely on regularisation procedures to remove infinities. Starting from special relativity and treating space and time coordinates equivalently, this paper overcomes no-go theorems of quantum electrodynamics and obtains a local relativistic quantum description of the electromagnetic field in free space. When extended to cavities, our approach can be used to calculate Casimir forces directly in position space without the introduction of cut-off frequencies.

On the cosmological constant

Does the Superluminal Neutrino Uncover Torsion?

I investigate the possibility of the propagation of neutrino with superluminal speed through matt... more I investigate the possibility of the propagation of neutrino with superluminal speed through matter in the context of the relation between gravity, spin and torsion. Using a lemma of Penrose and earlier works on the relation between spin, torsion and gravity I glimpse on a frame work in which superluminal speed of the neutrinos moving through matter become possible. In presence of torsoin neutrinos are found to follow spacelike geodesics by tunneling through the light cone into the spacelike region and consequently appear to have superluminal speed in our timelike world, whereas photons always follow null geodesics. This frame work may set new frontiers for spacetime physics.

Finite-temperature scalar fields and the cosmological constant in an Einstein universe

Physical Review D, 2003

We study the back-reaction effect of a massless minimally coupled scalar field at finite temperat... more We study the back-reaction effect of a massless minimally coupled scalar field at finite temperatures in the background of an Einstein universe. Substituting for the vacuum expectation value of the components of the energy-momentum tensor on the right hand side of the Einstein equation, we deduce a relationship between the radius of the universe and its temperature. This relationship exhibits a maximum temperature, below the Planck scale, at which the system changes its behavior drastically. The results are compared with the case of a conformally coupled field. An investigation into the values of the cosmological constant exhibits a remarkable difference between the conformally coupled case and the minimally coupled one.

Bose-Einstein condensation of spin-1 field in an Einstein universe

Journal of Physics A: Mathematical and General, 2000

In this paper we investigate the Bose-Einstein condensation of massive spin-1 particles in an Ein... more In this paper we investigate the Bose-Einstein condensation of massive spin-1 particles in an Einstein universe. The system is considered under relativistic conditions taking into consideration the possibility of particle-antiparticle pair production. An exact expression for the charge density is obtained, then certain approximations are employed in order to obtain the solutions in closed form. A discussion of the approximations employed in this and other work is given. The effects of finite-size and spin-curvature coupling are emphasized.

A Non-Singular Universe with Vacuum Energy

International Journal of Theoretical Physics, 2011

We construct a model for the universe based on the existence of quantum fields at finite temperat... more We construct a model for the universe based on the existence of quantum fields at finite temperature in the background of Robertson-Walker spacetime in presence of a non-zero cosmological constant. We discuss the vacuum regime in the light of the results obtained through previous studies of the back-reaction of massless quantum fields in the static Einstein universe, and we argue that an adiabatic vacuum state and thermal equilibrium is achieved throughout this regime. Results shows that such a model can explain many features of the early universe as well as the present universe. The model is free from the basic problems of the standard Friedmann cosmology, and is non-singular but involves a continuous creation of energy at a rate proportional to the size of the universe, which is lower than that suggested by the steady-state cosmology. Contents

Casimir Energy for Spherical Shell in Schwarzschild Black Hole Background

General Relativity and Gravitation, 2004

In this paper, we consider the Casimir energy of massless scalar field which satisfy Dirichlet bo... more In this paper, we consider the Casimir energy of massless scalar field which satisfy Dirichlet boundary condition on a spherical shell. Outside the shell, the spacetime is assumed to be described by the Schwarzschild metric, while inside the shell it is taken to be the flat Minkowski space. Using zeta function regularization and heat kernel coefficients we isolate the divergent contributions of the Casimir energy inside and outside the shell, then using the renormalization procedure of the bag model the divergent parts are cancelled, finally obtaining a renormalized expression for the total Casimir energy.

Back reaction of quantum fields in an Einstein universe

Physical Review D, 2002

We study the back-reaction effects of the finite-temperature massless scalar field and the photon... more We study the back-reaction effects of the finite-temperature massless scalar field and the photon field in the background of the static Einstein universe. In each case we find a relation between the temperature of the universe and its radius.These relations exhibit a minimum radius below which no self-consistent solution for the Einstein field equation can be found. A maximum temperature marks the transition from the vacuum dominated era to the radiation dominated era. An interpretation to this behavior in terms of Bose-Einstein condensation in the case of the scalar field is given.

An upper limit on the region of the particle creation by black holes

We follow a heuristic approach for particle creation by a localized strong gravitational field. T... more We follow a heuristic approach for particle creation by a localized strong gravitational field. The approach is based on a definition of the physical vacuum drawn from Heisenberg uncertainty principle. Using the fact that the gravitational field redshifts the frequency modes of the vacuum, a condition on the minimum strength of the gravitational field required to achieve real particle creation is derived. Application of this requirement on a Schwarzschild black hole resulted in deducing an upper limit on the region, outside the event horizon, where real particles can be created.

A quantum black hole universe

Using the result obtained in a prevoius paper, in which I found an upper limit on the region of p... more Using the result obtained in a prevoius paper, in which I found an upper limit on the region of particle creation in the vicinity of the event horizon of a Schwarzschild black hole, and by assuming that all the created energy will be absorbed by the black hole, a natural power law for the growth of the event horizon is deduced. This result may explain the existence of galactic black holes with very large masses. Application of this result on cosmological scale shows that if we start with a Planck-sized black hole then the natural growth of such a black hole will produce one with a density equals the present critical density of the universe. Such a black hole universe will be in the state of eternal inflation. Comment: 10 pages

Creation and the Personal Creator in Islamic Kalām and Modern Cosmology

The question of the eternity or temporality of the universe was thoroughly discussed by Muslim th... more The question of the eternity or temporality of the universe was thoroughly discussed by Muslim theologians. Most of them, principally those who were called Mutakallimūn, agreed on the notion of creation ex nihilo, i.e., creation out of nothing. On the other hand some Muslim philosophers adopted the Greek originated notion of an eternal universe that has existed forever without a beginning. In modern times the Kalām cosmological argument was revived by William Craig to be utilized as a logical reason for the existence of God. In this paper I will try to elucidate the fundamental Islamic arguments brought up by Mutakallimūn in support of the principle of creation and I will concentrate my study on arguments proposed by two main thinkers: the well-known theologian Ibn Hazm Al-Zāhirī and the well- recognized thinker Abu Hamid Al-Ghazālī. I then discuss some questions raised in connection with the philosophical implications of modern cosmology, including the role of the primary singulari...

Quantum black hole inflation

In this paper we follow a new approach for particle creation by a localized strong gravitational ... more In this paper we follow a new approach for particle creation by a localized strong gravitational field. The approach is based on a definition of the physical vacuum drawn from Heisenberg uncertainty principle. Using the fact that the gravitational field red-shifts the frequency modes of the vacuum, a condition on the minimum stregth of the gravitational field required to achieve real particle creation is derived. Application of this requirement on a Schwartzchid black hole resulted in deducing an upper limit on the region, outside the event horizon, where real particles can be created. Using this regional upper limit, and considering particle creation by black holes as a consequence of the Casimir effect, with the assumption that the created quanta are to be added to the initial energy, we deduce a natural power law for the development of the event horizon, and consequently a logarithmic law for the area spectrum of an inflating black hole. Application of the results on a cosmologic...

The Islamic Philosophy of Science A Study of Dakik al-Kalam

The Islamic Philosophy of Science A Study of Dakik al-Kalam

Spinor fields in an Einstein universe: Finite-temperature effects

Physical Review D, 1978

ABSTRACT The finite-temperature corrections to the vacuum energy density of scalar, neutrino, and... more ABSTRACT The finite-temperature corrections to the vacuum energy density of scalar, neutrino, and photon fields in an Einstein universe are calculated by using the statistical-mode-sum technique with the aid of the Poisson summation formula. The theory of relativistic time-temperature Green&#39;s functions in static space-time is also considered and used to calculate the temperature correction to the neutrino-field vacuum energy density. Asymptotic limits of low and high temperature are discussed for each case.

Bose-Einstein condensation in an Einstein universe

Journal of Physics A-mathematical and General, 1978

The condensation of a nonrelativistic ideal Bose gas in an Einstein universe is investigated. Exp... more The condensation of a nonrelativistic ideal Bose gas in an Einstein universe is investigated. Explicit expressions for the condensate fraction and the specific heat are obtained by using the Poisson summation formula to express the summation as integrations plus corrections. It is shown that the finiteness of the system smoothes out the cusp-like singularity of the infinite system. A rigorous asymptotic analysis of the critical temperature and the specific heat maximum are given, and the relation with the scaling theory of finite size effects is briefly discussed.

Spinor fields in an Einstein universe: Finite-temperature effects

Physical Review D, 1978

The finite-temperature corrections to the vacuum energy density of scalar, neutrino, and photon f... more The finite-temperature corrections to the vacuum energy density of scalar, neutrino, and photon fields in an Einstein universe are calculated by using the statistical-mode-sum technique with the aid of the Poisson summation formula. The theory of relativistic time-temperature Green's functions in static space-time is also considered and used to calculate the temperature correction to the neutrino-field vacuum energy density. Asymptotic limits of low and high temperature are discussed for each case.

Spinor fields in an Einstein Universe. The vacuum-averaged stress-energy tensor

Physical Review D, 1978

ABSTRACT The spin-1/2 Green&#39;s function in an Einstein universe is computed explicitly and... more

Spinor fields in an Einstein Universe. The vacuum-averaged stress-energy tensor

Physical Review D, 1978

The spin-1/2 Green's function in an Einstein universe is computed explicitly and used to evaluate... more

Time and Quantum Clocks: A Review of Recent Developments

Frontiers in Physics

In this review we present the problem of time in quantum physics, including a short history of th... more In this review we present the problem of time in quantum physics, including a short history of the problem and the known objections about considering time as a quantum observable. The need to deal with time as an observable is elaborated through some unresolved problems. The lack of a consistent theory of time is currently hindering the formulation of a full-fledged theory of quantum gravity. It is argued that the proposal set forth by several authors of considering an intrinsic measurement of quantum time, besides having the conventional external time, is compelling. Recently several suggestions have been put forward to revive the proposal of Page and Wootters (1983), elaborating and resolving some of the main ambiguities of the original proposal and opening new scope for understanding its content. The approach followed in these new contributions exposes the need to go beyond the limitations enforced by the conventional approach of quantum physics. The attitude of covariant loop qu...

An intuitive picture of the Casimir effect

The Casimir effect, which predicts the emergence of an attractive force between two parallel, hig... more The Casimir effect, which predicts the emergence of an attractive force between two parallel, highly reflecting plates in vacuum, plays a vital role in various fields of physics, from quantum field theory and cosmology to nanophotonics and condensed matter physics. Nevertheless, Casimir forces still lack an intuitive explanation and current derivations rely on regularisation procedures to remove infinities. Starting from special relativity and treating space and time coordinates equivalently, this paper overcomes no-go theorems of quantum electrodynamics and obtains a local relativistic quantum description of the electromagnetic field in free space. When extended to cavities, our approach can be used to calculate Casimir forces directly in position space without the introduction of cut-off frequencies.

On the cosmological constant

Does the Superluminal Neutrino Uncover Torsion?

I investigate the possibility of the propagation of neutrino with superluminal speed through matt... more I investigate the possibility of the propagation of neutrino with superluminal speed through matter in the context of the relation between gravity, spin and torsion. Using a lemma of Penrose and earlier works on the relation between spin, torsion and gravity I glimpse on a frame work in which superluminal speed of the neutrinos moving through matter become possible. In presence of torsoin neutrinos are found to follow spacelike geodesics by tunneling through the light cone into the spacelike region and consequently appear to have superluminal speed in our timelike world, whereas photons always follow null geodesics. This frame work may set new frontiers for spacetime physics.

Finite-temperature scalar fields and the cosmological constant in an Einstein universe

Physical Review D, 2003

We study the back-reaction effect of a massless minimally coupled scalar field at finite temperat... more We study the back-reaction effect of a massless minimally coupled scalar field at finite temperatures in the background of an Einstein universe. Substituting for the vacuum expectation value of the components of the energy-momentum tensor on the right hand side of the Einstein equation, we deduce a relationship between the radius of the universe and its temperature. This relationship exhibits a maximum temperature, below the Planck scale, at which the system changes its behavior drastically. The results are compared with the case of a conformally coupled field. An investigation into the values of the cosmological constant exhibits a remarkable difference between the conformally coupled case and the minimally coupled one.

Bose-Einstein condensation of spin-1 field in an Einstein universe

Journal of Physics A: Mathematical and General, 2000

In this paper we investigate the Bose-Einstein condensation of massive spin-1 particles in an Ein... more In this paper we investigate the Bose-Einstein condensation of massive spin-1 particles in an Einstein universe. The system is considered under relativistic conditions taking into consideration the possibility of particle-antiparticle pair production. An exact expression for the charge density is obtained, then certain approximations are employed in order to obtain the solutions in closed form. A discussion of the approximations employed in this and other work is given. The effects of finite-size and spin-curvature coupling are emphasized.

A Non-Singular Universe with Vacuum Energy

International Journal of Theoretical Physics, 2011

We construct a model for the universe based on the existence of quantum fields at finite temperat... more We construct a model for the universe based on the existence of quantum fields at finite temperature in the background of Robertson-Walker spacetime in presence of a non-zero cosmological constant. We discuss the vacuum regime in the light of the results obtained through previous studies of the back-reaction of massless quantum fields in the static Einstein universe, and we argue that an adiabatic vacuum state and thermal equilibrium is achieved throughout this regime. Results shows that such a model can explain many features of the early universe as well as the present universe. The model is free from the basic problems of the standard Friedmann cosmology, and is non-singular but involves a continuous creation of energy at a rate proportional to the size of the universe, which is lower than that suggested by the steady-state cosmology. Contents

Casimir Energy for Spherical Shell in Schwarzschild Black Hole Background

General Relativity and Gravitation, 2004

In this paper, we consider the Casimir energy of massless scalar field which satisfy Dirichlet bo... more In this paper, we consider the Casimir energy of massless scalar field which satisfy Dirichlet boundary condition on a spherical shell. Outside the shell, the spacetime is assumed to be described by the Schwarzschild metric, while inside the shell it is taken to be the flat Minkowski space. Using zeta function regularization and heat kernel coefficients we isolate the divergent contributions of the Casimir energy inside and outside the shell, then using the renormalization procedure of the bag model the divergent parts are cancelled, finally obtaining a renormalized expression for the total Casimir energy.

Back reaction of quantum fields in an Einstein universe

Physical Review D, 2002

We study the back-reaction effects of the finite-temperature massless scalar field and the photon... more We study the back-reaction effects of the finite-temperature massless scalar field and the photon field in the background of the static Einstein universe. In each case we find a relation between the temperature of the universe and its radius.These relations exhibit a minimum radius below which no self-consistent solution for the Einstein field equation can be found. A maximum temperature marks the transition from the vacuum dominated era to the radiation dominated era. An interpretation to this behavior in terms of Bose-Einstein condensation in the case of the scalar field is given.

An upper limit on the region of the particle creation by black holes

We follow a heuristic approach for particle creation by a localized strong gravitational field. T... more We follow a heuristic approach for particle creation by a localized strong gravitational field. The approach is based on a definition of the physical vacuum drawn from Heisenberg uncertainty principle. Using the fact that the gravitational field redshifts the frequency modes of the vacuum, a condition on the minimum strength of the gravitational field required to achieve real particle creation is derived. Application of this requirement on a Schwarzschild black hole resulted in deducing an upper limit on the region, outside the event horizon, where real particles can be created.

A quantum black hole universe

Using the result obtained in a prevoius paper, in which I found an upper limit on the region of p... more Using the result obtained in a prevoius paper, in which I found an upper limit on the region of particle creation in the vicinity of the event horizon of a Schwarzschild black hole, and by assuming that all the created energy will be absorbed by the black hole, a natural power law for the growth of the event horizon is deduced. This result may explain the existence of galactic black holes with very large masses. Application of this result on cosmological scale shows that if we start with a Planck-sized black hole then the natural growth of such a black hole will produce one with a density equals the present critical density of the universe. Such a black hole universe will be in the state of eternal inflation. Comment: 10 pages

Creation and the Personal Creator in Islamic Kalām and Modern Cosmology

The question of the eternity or temporality of the universe was thoroughly discussed by Muslim th... more The question of the eternity or temporality of the universe was thoroughly discussed by Muslim theologians. Most of them, principally those who were called Mutakallimūn, agreed on the notion of creation ex nihilo, i.e., creation out of nothing. On the other hand some Muslim philosophers adopted the Greek originated notion of an eternal universe that has existed forever without a beginning. In modern times the Kalām cosmological argument was revived by William Craig to be utilized as a logical reason for the existence of God. In this paper I will try to elucidate the fundamental Islamic arguments brought up by Mutakallimūn in support of the principle of creation and I will concentrate my study on arguments proposed by two main thinkers: the well-known theologian Ibn Hazm Al-Zāhirī and the well- recognized thinker Abu Hamid Al-Ghazālī. I then discuss some questions raised in connection with the philosophical implications of modern cosmology, including the role of the primary singulari...

Quantum black hole inflation

In this paper we follow a new approach for particle creation by a localized strong gravitational ... more In this paper we follow a new approach for particle creation by a localized strong gravitational field. The approach is based on a definition of the physical vacuum drawn from Heisenberg uncertainty principle. Using the fact that the gravitational field red-shifts the frequency modes of the vacuum, a condition on the minimum stregth of the gravitational field required to achieve real particle creation is derived. Application of this requirement on a Schwartzchid black hole resulted in deducing an upper limit on the region, outside the event horizon, where real particles can be created. Using this regional upper limit, and considering particle creation by black holes as a consequence of the Casimir effect, with the assumption that the created quanta are to be added to the initial energy, we deduce a natural power law for the development of the event horizon, and consequently a logarithmic law for the area spectrum of an inflating black hole. Application of the results on a cosmologic...

The Islamic Philosophy of Science A Study of Dakik al-Kalam

The Islamic Philosophy of Science A Study of Dakik al-Kalam

Spinor fields in an Einstein universe: Finite-temperature effects

Physical Review D, 1978

ABSTRACT The finite-temperature corrections to the vacuum energy density of scalar, neutrino, and... more ABSTRACT The finite-temperature corrections to the vacuum energy density of scalar, neutrino, and photon fields in an Einstein universe are calculated by using the statistical-mode-sum technique with the aid of the Poisson summation formula. The theory of relativistic time-temperature Green&#39;s functions in static space-time is also considered and used to calculate the temperature correction to the neutrino-field vacuum energy density. Asymptotic limits of low and high temperature are discussed for each case.

Bose-Einstein condensation in an Einstein universe

Journal of Physics A-mathematical and General, 1978

The condensation of a nonrelativistic ideal Bose gas in an Einstein universe is investigated. Exp... more The condensation of a nonrelativistic ideal Bose gas in an Einstein universe is investigated. Explicit expressions for the condensate fraction and the specific heat are obtained by using the Poisson summation formula to express the summation as integrations plus corrections. It is shown that the finiteness of the system smoothes out the cusp-like singularity of the infinite system. A rigorous asymptotic analysis of the critical temperature and the specific heat maximum are given, and the relation with the scaling theory of finite size effects is briefly discussed.

Spinor fields in an Einstein universe: Finite-temperature effects

Physical Review D, 1978

The finite-temperature corrections to the vacuum energy density of scalar, neutrino, and photon f... more The finite-temperature corrections to the vacuum energy density of scalar, neutrino, and photon fields in an Einstein universe are calculated by using the statistical-mode-sum technique with the aid of the Poisson summation formula. The theory of relativistic time-temperature Green's functions in static space-time is also considered and used to calculate the temperature correction to the neutrino-field vacuum energy density. Asymptotic limits of low and high temperature are discussed for each case.

Spinor fields in an Einstein Universe. The vacuum-averaged stress-energy tensor

Physical Review D, 1978

ABSTRACT The spin-1/2 Green&#39;s function in an Einstein universe is computed explicitly and... more

Spinor fields in an Einstein Universe. The vacuum-averaged stress-energy tensor

Physical Review D, 1978

The spin-1/2 Green's function in an Einstein universe is computed explicitly and used to evaluate... more