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Search Results: 1 - 10 of 201315 matches for " Stephen G. Low "
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Relativity group for noninertial frames in Hamilton's mechanics
Stephen G. Low
Physics , 2007, DOI: 10.1063/1.2789553
Abstract: The group E(3)=SO(3) *s T(3), that is the homogeneous subgroup of the Galilei group parameterized by rotation angles and velocities, defines the continuous group of transformations between the frames of inertial particles in Newtonian mechanics. We show in this paper that the continuous group of transformations between the frames of noninertial particles following trajectories that satisfy Hamilton's equations is given by the Hamilton group Ha(3)=SO(3) *s H(3) where H(3) is the Weyl-Heisenberg group that is parameterized by rates of change of position, momentum and energy, i.e. velocity, force and power. The group E(3) is the inertial special case of the Hamilton group.
Hamilton relativity group for noninertial states in quantum mechanics
Stephen G. Low
Physics , 2007, DOI: 10.1088/1751-8113/41/30/304034
Abstract: Physical states in quantum mechanics are rays in a Hilbert space. Projective representations of a relativity group transform between the quantum physical states that are in the admissible class. The physical observables of position, time, energy and momentum are the Hermitian representation of the Weyl-Heisenberg algebra. We show that there is a consistency condition that requires the relativity group to be a subgroup of the group of automorphisms of the Weyl-Heisenberg algebra. This, together with the requirement of the invariance of classical time, results in the inhomogeneous Hamilton group that is the relativity group for noninertial frames in classical Hamilton's mechanics. The projective representation of a group is equivalent to unitary representations of its central extension. The central extension of the inhomogeneous Hamilton group and its corresponding Casimir invariants are computed. One of the Casimir invariants is a generalized spin that is invariant for noninertial states. It is the familiar inertial Galilean spin with additional terms that may be compared to noninertial experimental results.
Canonically Relativistic Quantum Mechanics: Representations of the Unitary Semidirect Heisenberg Group, U(1,3) *s H(1,3)
Stephen G. Low
Physics , 1997, DOI: 10.1063/1.531968
Abstract: Born proposed a unification of special relativity and quantum mechanics that placed position, time, energy and momentum on equal footing through a reciprocity principle and extended the usual position-time and energy-momentum line elements to this space by combining them through a new fundamental constant. Requiring also invariance of the symplectic metric yields U(1,3) as the invariance group, the inhomogeneous counterpart of which is the canonically relativistic group CR(1,3) = U(1,3) *s H(1,3) where H(1,3) is the Heisenberg Group in 4 dimensions and "*s" is the semidirect product. This is the counterpart in this theory of the Poincare group and reduces in the appropriate limit to the expected special relativity and classical Hamiltonian mechanics transformation equations. This group has the Poincare group as a subgroup and is intrinsically quantum with the Position, Time, Energy and Momentum operators satisfying the Heisenberg algebra. The representations of the algebra are studied and Casimir invariants are computed. Like the Poincare group, it has a little group for a ("massive") rest frame and a null frame. The former is U(3) which clearly contains SU(3) and the latter is Os(2) which contains SU(2)*U(1).
Noninertial symmetry group with invariant Minkowski line element consistent with Heisenberg quantum commutation relations
Stephen G. Low
Physics , 2008, DOI: 10.1088/1742-6596/284/1/012045
Abstract: The maximal symmetry of a quantum system with Heisenberg commutation relations is given by the projective representations of the automorphism group of the Weyl-Heisenberg algebra. The automorphism group is the central extension of the inhomogeneous symplectic group with a conformal scaling that acts on extended phase space. We determine the subgroup that also leaves invariant a degenerate orthogonal Minkowski line element. This defines noninertial relativistic symmetry transformations that have the expected classical limit as c becomes infinite.
Noninertial Symmetry Group of Hamilton's Mechanics
Stephen G. Low
Physics , 2009,
Abstract: We present a new derivation of Hamilton's equations that shows that they have a symmetry group Sp(2n) *s H(n). Sp(2n) is the symplectic group and H(n) is mathematically a Weyl-Heisenberg group that is parameterized by velocity, force and power where power is the central element of the group. We present a new derivation of Hamilton's equations that shows that they have a symmetry group Sp(2n) *s H(n). The group Sp(2n) is the real noncompact symplectic group and H(n) is mathematically a Weyl-Heisenberg group that is parameterized by velocity, force and power where power is the central element of the group. The homogeneous Galilei group SO(n) *s A(n), where the special orthogonal group SO(n) is parameterized by rotations and the abelian group A(n)is parameterized by velocity, is the inertial subgroup.
Relativity implications of the quantum phase
Stephen G. Low
Physics , 2009, DOI: 10.1088/1742-6596/343/1/012069
Abstract: The quantum phase leads to projective representations of symmetry groups in quantum mechanics. The projective representations are equivalent to the unitary representations of the central extension of the group. A celebrated example is Wigner's formulation of special relativistic quantum mechanics as the projective representations of the inhomogeneous Lorentz group. However, Wigner's formulation makes no mention of the Weyl-Heisenberg group and the hermitian representation of its algebra that are the Heisenberg commutation relations fundamental to quantum physics. We put aside the relativistic symmetry and show that the maximal quantum symmetry that leaves the Heisenberg commutation relations invariant is the projective representations of the conformally scaled inhomogeneous symplectic group. The Weyl-Heisenberg group and noncommutative structure arises directly because the quantum phase requires projective representations. We then consider the relativistic implications of the quantum phase that lead to the Born line element and the projective representations of an inhomogeneous unitary group that defines a noninertial quantum theory. (Understanding noninertial quantum mechanics is a prelude to understanding quantum gravity.) The remarkable properties of this symmetry and its limits are studied.
Representations of the Canonical group, (the semi-direct product of the Unitary and Weyl-Heisenberg groups), acting as a dynamical group on noncommuting extended phase space
Stephen G. Low
Physics , 2001, DOI: 10.1088/0305-4470/35/27/312
Abstract: The unitary irreducible representations of the covering group of the Poincare group P define the framework for much of particle physics on the physical Minkowski space P/L, where L is the Lorentz group. While extraordinarily successful, it does not provide a large enough group of symmetries to encompass observed particles with a SU(3) classification. Born proposed the reciprocity principle that states physics must be invariant under the reciprocity transform that is heuristically {t,e,q,p}->{t,e,p,-q} where {t,e,q,p} are the time, energy, position, and momentum degrees of freedom. This implies that there is reciprocally conjugate relativity principle such that the rates of change of momentum must be bounded by b, where b is a universal constant. The appropriate group of dynamical symmetries that embodies this is the Canonical group C(1,3) = U(1,3) *s H(1,3) and in this theory the non-commuting space Q= C(1,3)/ SU(1,3) is the physical quantum space endowed with a metric that is the second Casimir invariant of the Canonical group, T^2 + E^2 - Q^2/c^2-P^2/b^2 +(2h I/bc)(Y/bc -2) where {T,E,Q,P,I,Y} are the generators of the algebra of Os(1,3). The idea is to study the representations of the Canonical dynamical group using Mackey's theory to determine whether the representations can encompass the spectrum of particle states. The unitary irreducible representations of the Canonical group contain a direct product term that is a representation of U(1,3) that Kalman has studied as a dynamical group for hadrons. The U(1,3) representations contain discrete series that may be decomposed into infinite ladders where the rungs are representations of U(3) (finite dimensional) or C(2) (with degenerate U(1)* SU(2) finite dimensional representations) corresponding to the rest or null frames.
Poincare and Heisenberg quantum dynamical symmetry: Casimir invariant field equations of the quaplectic group
Stephen G. Low
Mathematics , 2005,
Abstract: The unitary irreducible representations of a Lie group defines the Hilbert space on which the representations act. If this Lie group is a physical quantum dynamical symmetry group, this Hilbert space is identified with the physical quantum state space. The eigenvalue equations for the representation of the set of Casimir invariant operators define the field equations of the system. The Poincare group is the archetypical example with the unitary representations defining the Hilbert space of relativistic particle states and the Klein-Gordon, Dirac, Maxwell equations are obtained from the representations of the Casimir invariant operators eigenvalue equations. The representation of the Heisenberg group does not appear in this derivation. The unitary representations of the Heisenberg group, however, play a fundamental role in nonrelativistic quantum mechanics, defining the Hilbert space and the basic momentum and position commutation relations. Viewing the Heisenberg group as a generalized non-abelian "translation" group, we look for a semidirect product group with it as the normal subgroup that also contains the Poincare group. The quaplectic group, that is derived from a simple argument using Born's orthogonal metric hypothesis, contains four Poincare subgroups as well as the normal Heisenberg subgroup. The general set of field equations are derived using the Mackey representation theory for general semidirect product groups.
Maximal quantum mechanical symmetry: Projective representations of the inhomogenous symplectic group
Stephen G. Low
Mathematics , 2012, DOI: 10.1063/1.4863896
Abstract: A symmetry in quantum mechanics is described by the projective representations of a Lie symmetry group that transforms between physical quantum states such that the square of the modulus of the states is invariant. The Heisenberg commutation relations, that are fundamental to quantum mechanics, must be valid in all of these physical states. This paper shows that the maximal quantum symmetry group, whose projective representations preserve the Heisenberg commutation relations in this manner, is the inhomogeneous symplectic group. The projective representations are equivalent to the unitary representations of the central extension of the inhomogeneous symplectic group. This centrally extended group is the semidirect product of the cover of the symplectic group and the Weyl-Heisenberg group. Its unitary irreducible representations are computed explicitly using the Mackey representation theorems for semidirect product groups.
Reciprocal relativity of noninertial frames and the quaplectic group
Stephen G. Low
Mathematics , 2005, DOI: 10.1007/s10701-006-9051-2
Abstract: Newtonian mechanics has the concept of an absolute inertial rest frame. Special relativity eliminates the absolute rest frame but continues to require the absolute inertial frame. General relativity solves this for gravity by requiring particles to have locally inertial frames on a curved position-time manifold. The problem of the absolute inertial frame for other forces remains. We look again at the transformations of frames on an extended phase space with position, time, energy and momentum degrees of freedom. Under nonrelativistic assumptions, there is an invariant symplectic metric and a line element dt^2. Under special relativistic assumptions the symplectic metric continues to be invariant but the line elements are now -dt^2+dq^2/c^2 and dp^2-de^2/c^2. Max Born conjectured that the line element should be generalized to the pseudo- orthogonal metric -dt^2+dq^2/c^2+ (1/b^2)(dp^2-de^2/c^2). The group leaving these two metrics invariant is the pseudo-unitary group of transformations between noninertial frames. We show that these transformations eliminate the need for an absolute inertial frame by making forces relative and bounded by b and so embodies a relativity that is 'reciprocal' in the sense of Born. The inhomogeneous version of this group is naturally the semidirect product of the pseudo-unitary group with the nonabelian Heisenberg group. This is the quaplectic group. The Heisenberg group itself is the semidirect product of two translation groups. This provides the noncommutative properties of position and momentum and also time and energy that are required for the quantum mechanics that results from considering the unitary representations of the quaplectic group.
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