Lorentz Invariance:. Present Experimental Status
NASA Astrophysics Data System (ADS)
Lämmerzahl, Claus
2006-02-01
Being one of the pillars of modern physics, Lorentz invariance has to be tested as precisely as possible. We review the present status of laboratory tests of Lorentz invariance. This includes the tests of properties of light propagation which are covered by the famous Michelson-Morley, Kennedy-Thorndike, and Ives-Stilwell experiments, as well as tests on dynamical properties of matter as, e.g., tests exploring the maximum velocity of massive particles or tests of the isotropy of quantum particles in Hughes-Drever experiments.
CPT violation implies violation of Lorentz invariance.
Greenberg, O W
2002-12-02
A interacting theory that violates CPT invariance necessarily violates Lorentz invariance. On the other hand, CPT invariance is not sufficient for out-of-cone Lorentz invariance. Theories that violate CPT by having different particle and antiparticle masses must be nonlocal.
Lorentz invariance in loop quantum gravity
NASA Astrophysics Data System (ADS)
Pullin, Jorge; Rastgoo, Saeed; Gambini, Rodolfo
2011-04-01
We reconsider the argument of Collins, Perez, Sudarsky, Urrutia and Vucetich concerning violations of Lorentz invariance in the context of loop quantum gravity. We show that even if one introduces a lattice that violates Lorentz invariance at the Planck scale, this does not translate itself into large violations that would conflict with experiment.
Tests of Lorentz invariance using hydrogen molecules
Mueller, Holger; Herrmann, Sven; Saenz, Alejandro; Peters, Achim; Laemmerzahl, Claus
2004-10-01
We discuss the consequences of Lorentz violation (as expressed within the Lorentz-violating extension of the standard model) for the hydrogen molecule, which represents a generic model of a molecular binding. Lorentz-violating shifts of electronic, vibrational and rotational energy levels, and of the internuclear distance are calculated. This offers the possibility of obtaining improved bounds on Lorentz invariance by experiments using molecules.
South Pole Lorentz Invariance Test
NASA Astrophysics Data System (ADS)
Hedges, Morgan; Smiciklas, Marc; Romalis, Michael
2015-05-01
Searches for Lorentz and CPT violation play an important role in testing current theories of space-time. To test one of the consequences of local Lorentz invariance we have performed a precision test of spatial isotropy at the Amundsen-Scott station near the geographic South Pole. This location provides the most isotropic environment available on Earth. The experiment is a rotating atomic-spin co-magnetometer which compares energy levels of 21Ne and Rubidium atoms as a function of direction. The experimental sensitivity obtained is more than an order of magnitude better than in previous such measurements, known as Hughes-Drever experiments. By operating the experiment at the Pole we are able to eliminate background signals due to the gyroscopic interactions of spins with Earth's rotation as well as diurnal environmental effects. Here we will present final results from the experiment's 2-year data collection period. This is the first precision atomic physics experiment performed at the Pole, and we will discuss the potential for future such measurements.
South Pole Lorentz Invariance Test
NASA Astrophysics Data System (ADS)
Hedges, Morgan; Smiciklas, Marc; Romalis, Michael
2015-04-01
Tests of Lorentz and CPT symmetries are important because they form a cornerstone of quantum field theory and general relativity. To test one of the consequences of local Lorentz invariance we have performed a precision test of spatial isotropy at the Amundsen-Scott station near the geographic South Pole. This location provides the most isotropic environment available on Earth. We use an atomic spin co-magnetometer to compare energy levels in 21 Ne and Rubidium atoms as the apparatus rotates with respect to the cosmos. Our experimental sensitivity is more than an order of magnitude greater than in previous such measurements, known as Hughes-Drever experiments. By operating at the South Pole we eliminate background signals due to the gyroscopic interactions of spins with Earth's rotation as well as diurnal environmental effects. The experiment has finished a 2-year data collection period and we expect to present the final results at the meeting. This is the first precision atomic physics experiment performed at the Pole and we will discuss the potential for future such measurements.
Testing local Lorentz invariance with gravitational waves
Kostelecký, V. Alan; Mewes, Matthew
2016-04-20
The effects of local Lorentz violation on dispersion and birefringence of gravitational waves are investigated. The covariant dispersion relation for gravitational waves involving gauge-invariant Lorentz violating operators of arbitrary mass dimension is constructed. The chirp signal from the gravitational wave event GW150914 is used to place numerous first constraints on gravitational Lorentz violation. (C) 2016 The Authors. Published by Elsevier B.V.
Neutrinos as Probes of Lorentz Invariance
Díaz, Jorge S.
2014-01-01
Neutrinos can be used to search for deviations from exact Lorentz invariance. The worldwide experimental program in neutrino physics makes these particles a remarkable tool to search for a variety of signals that could reveal minute relativity violations. This paper reviews the generic experimental signatures of the breakdown of Lorentz symmetry in the neutrino sector.
Testing Lorentz invariance of dark matter
Blas, Diego; Ivanov, Mikhail M.; Sibiryakov, Sergey E-mail: mm.ivanov@physics.msu.ru
2012-10-01
We study the possibility to constrain deviations from Lorentz invariance in dark matter (DM) with cosmological observations. Breaking of Lorentz invariance generically introduces new light gravitational degrees of freedom, which we represent through a dynamical timelike vector field. If DM does not obey Lorentz invariance, it couples to this vector field. We find that this coupling affects the inertial mass of small DM halos which no longer satisfy the equivalence principle. For large enough lumps of DM we identify a (chameleon) mechanism that restores the inertial mass to its standard value. As a consequence, the dynamics of gravitational clustering are modified. Two prominent effects are a scale dependent enhancement in the growth of large scale structure and a scale dependent bias between DM and baryon density perturbations. The comparison with the measured linear matter power spectrum in principle allows to bound the departure from Lorentz invariance of DM at the per cent level.
On Lorentz invariants in relativistic magnetic reconnection
Yang, Shu-Di; Wang, Xiao-Gang
2016-08-15
Lorentz invariants whose nonrelativistic correspondences play important roles in magnetic reconnection are discussed in this paper. Particularly, the relativistic invariant of the magnetic reconnection rate is defined and investigated in a covariant two-fluid model. Certain Lorentz covariant representations for energy conversion and magnetic structures in reconnection processes are also investigated. Furthermore, relativistic measures for topological features of reconnection sites, particularly magnetic nulls and separatrices, are analyzed.
Lorentz invariance in chiral kinetic theory.
Chen, Jing-Yuan; Son, Dam T; Stephanov, Mikhail A; Yee, Ho-Ung; Yin, Yi
2014-10-31
We show that Lorentz invariance is realized nontrivially in the classical action of a massless spin-1/2 particle with definite helicity. We find that the ordinary Lorentz transformation is modified by a shift orthogonal to the boost vector and the particle momentum. The shift ensures angular momentum conservation in particle collisions and implies a nonlocality of the collision term in the Lorentz-invariant kinetic theory due to side jumps. We show that 2/3 of the chiral-vortical effect for a uniformly rotating particle distribution can be attributed to the magnetic moment coupling required by the Lorentz invariance. We also show how the classical action can be obtained by taking the classical limit of the path integral for a Weyl particle.
Light-bending tests of Lorentz invariance
Tso, Rhondale; Bailey, Quentin G.
2011-10-15
Classical light-bending is investigated for weak gravitational fields in the presence of hypothetical local Lorentz violation. Using an effective field theory framework that describes general deviations from local Lorentz invariance, we derive a modified deflection angle for light passing near a massive body. The results include anisotropic effects not present for spherical sources in General Relativity as well as Weak Equivalence Principle violation. We develop an expression for the relative deflection of two distant stars that can be used to analyze data in past and future solar-system observations. The measurement sensitivities of such tests to coefficients for Lorentz violation are discussed.
From scale invariance to Lorentz symmetry.
Sibiryakov, Sergey
2014-06-20
It is shown that a unitary translationally invariant field theory in 1+1 dimensions, satisfying isotropic scale invariance, standard assumptions about the spectrum of states and operators, and the requirement that signals propagate with finite velocity, possesses an infinite dimensional symmetry given by one or a product of several copies of conformal algebra. In particular, this implies the presence of one or several Lorentz groups acting on the operator algebra of the theory.
South Pole Lorentz Invariance Test
NASA Astrophysics Data System (ADS)
Hedges, Morgan; Smiciklas, Marc; Romalis, Michael
2014-05-01
Atomic spin co-magnetometers are among the most sensitive instruments to test for violations of CPT and Lorentz symmetry. Our rotating co-magnetometer has, in recent years, set the most stringent limits for such violations in fermions with measurements conducted in Princeton. In order to eliminate the gyroscopic pickup of Earth's rotation as a major limiting background, we now operate a Rb-21Ne co-magnetometer at the Amundsen-Scott South Pole Station. We discuss the current status of our ongoing South Pole experiment along with the latest results. This research is funded by NSF grant #PLR-1142032.
Remarks on holography with broken Lorentz invariance
NASA Astrophysics Data System (ADS)
Gordeli, Ivan; Koroteev, Peter
2009-12-01
Recently a family of solutions of Einstein equations in backgrounds with broken Lorentz invariance was found. We show that the gravitational solution recently obtained by Kachru et al. is a part of the former solution which was derived earlier in the framework of extra-dimensional theories. We show how the energy-momentum and Einstein tensors are related and establish a correspondence between parameters which govern Lorentz invariance violation. Then we demonstrate that scaling behavior of two point correlation functions of local operators in scalar field theory is reproduced correctly for two cases with critical values of scaling parameters. Therefore, we complete the dictionary of “tree-level” duality for all known solutions of the bulk theory. In the end we speculate on relations between renormalization group flow of a boundary theory and asymptotic behavior of gravitational solutions in the bulk.
Neutrino velocity and local Lorentz invariance
NASA Astrophysics Data System (ADS)
Cardone, Fabio; Mignani, Roberto; Petrucci, Andrea
2015-09-01
We discuss the possible violation of local Lorentz invariance (LLI) arising from a faster-than-light neutrino speed. A toy calculation of the LLI violation parameter δ, based on the (disclaimed) OPERA data, suggests that the values of δ are determined by the interaction involved, and not by the energy range. This hypothesis is further corroborated by the analysis of the more recent results of the BOREXINO, LVD and ICARUS experiments.
Astroparticle Physics Tests of Lorentz Invariance Violation
NASA Astrophysics Data System (ADS)
Lang, R. G.; de Souza, V.
2017-06-01
Testing Lorentz invariance is essential as it is one of the pillars of modern physics. Moreover, its violation is foreseen in several popular Quantum Gravity models. Several authors study the effects of Lorentz invariance violation (LIV) in the propagation of ultra-high energy cosmic rays. These particles are the most energetic events ever detected and therefore represent a promising framework to test LIV. In this work we present an analytic calculation of the inelasticity for any a + b → c + d interaction using first order perturbation in the dispersion relation that violates Lorentz invariance. The inelasticity can be calculated by solving a third-order polynomial equation containing: a) the kinematics of the interaction, b) the LIV term for each particle and c) the geometry of the interaction. We use the inelasticity we calculate to investigate the proton propagation in the intergalactic media. The photopion production of the proton interaction with the CMB is taken into account using the inelasticity and the attenuation length in different LIV scenarios. We show how the allowed phase space for the photopion production changes when LIV is considered for the interaction. The calculations presented here are going to be extended in order to calculated the modified ultra-high energy cosmic rays spectrum and compare it to the data.
Are the invariance principles really truly Lorentz covariant?
Arunasalam, V.
1994-02-01
It is shown that some sections of the invariance (or symmetry) principles such as the space reversal symmetry (or parity P) and time reversal symmetry T (of elementary particle and condensed matter physics, etc.) are not really truly Lorentz covariant. Indeed, I find that the Dirac-Wigner sense of Lorentz invariance is not in full compliance with the Einstein-Minkowski reguirements of the Lorentz covariance of all physical laws (i.e., the world space Mach principle).
QCD breaks Lorentz invariance and colour
NASA Astrophysics Data System (ADS)
Balachandran, A. P.
2016-03-01
In the previous work [A. P. Balachandran and S. Vaidya, Eur. Phys. J. Plus 128, 118 (2013)], we have argued that the algebra of non-Abelian superselection rules is spontaneously broken to its maximal Abelian subalgebra, that is, the algebra generated by its completing commuting set (the two Casimirs, isospin and a basis of its Cartan subalgebra). In this paper, alternative arguments confirming these results are presented. In addition, Lorentz invariance is shown to be broken in quantum chromodynamics (QCD), just as it is in quantum electrodynamics (QED). The experimental consequences of these results include fuzzy mass and spin shells of coloured particles like quarks, and decay life times which depend on the frame of observation [D. Buchholz, Phys. Lett. B 174, 331 (1986); D. Buchholz and K. Fredenhagen, Commun. Math. Phys. 84, 1 (1982; J. Fröhlich, G. Morchio and F. Strocchi, Phys. Lett. B 89, 61 (1979); A. P. Balachandran, S. Kürkçüoğlu, A. R. de Queiroz and S. Vaidya, Eur. Phys. J. C 75, 89 (2015); A. P. Balachandran, S. Kürkçüoğlu and A. R. de Queiroz, Mod. Phys. Lett. A 28, 1350028 (2013)]. In a paper under preparation, these results are extended to the ADM Poincaré group and the local Lorentz group of frames. The renormalisation of the ADM energy by infrared gravitons is also studied and estimated.
The Superluminal Neutrinos from Deformed Lorentz Invariance
NASA Astrophysics Data System (ADS)
Huo, Yunjie; Li, Tianjun; Liao, Yi; Nanopoulos, Dimitri V.; Qi, Yonghui; Wang, Fei
2012-10-01
We study two superluminal neutrino scenarios where δ v≡ (v-c)/(c) is a constant. To be consistent with the OPERA, Borexino and ICARUS experiments and with the SN1987a observations, we assume that δvν on the Earth is about three-order larger than that on the interstellar scale. To explain the theoretical challenges from the Bremsstrahlung effects and pion decays, we consider the deformed Lorentz invariance, and show that the superluminal neutrino dispersion relations can be realized properly while the modifications to the dispersion relations of the other Standard Model particles can be negligible. In addition, we propose the deformed energy and momentum conservation laws for a generic physical process. In Scenario I the momentum conservation law is preserved while the energy conservation law is deformed. In Scenario II the energy conservation law is preserved while the momentum conservation law is deformed. We present the energy and momentum conservation laws in terms of neutrino momentum in Scenario I and in terms of neutrino energy in Scenario II. In such formats, the energy and momentum conservation laws are exactly the same as those in the traditional quantum field theory with Lorentz symmetry. Thus, all the above theoretical challenges can be automatically solved. We show explicitly that the Bremsstrahlung processes are forbidden and there is no problem for pion decays.
MACRO constraints on violation of Lorentz invariance
NASA Astrophysics Data System (ADS)
Cozzi, M.
2007-06-01
The energy spectrum of neutrino-induced upward-going muons in MACRO has been analysed in terms of relativity principles violating effects, keeping standard mass-induced atmospheric neutrino oscillations as the dominant source of ν→ν transitions. The data disfavor these exotic possibilities even at a sub-dominant level, and stringent 90% C.L. limits are placed on the Lorentz invariance violation parameter |Δv|<6×10 at sin2θ=0 and |Δv|<2.5÷5×10 at sin2θ=±1. These limits can also be re-interpreted as upper bounds on the parameters describing violation of the Equivalence Principle.
Lorentz invariance violation and generalized uncertainty principle
NASA Astrophysics Data System (ADS)
Tawfik, Abdel Nasser; Magdy, H.; Ali, A. Farag
2016-01-01
There are several theoretical indications that the quantum gravity approaches may have predictions for a minimal measurable length, and a maximal observable momentum and throughout a generalization for Heisenberg uncertainty principle. The generalized uncertainty principle (GUP) is based on a momentum-dependent modification in the standard dispersion relation which is conjectured to violate the principle of Lorentz invariance. From the resulting Hamiltonian, the velocity and time of flight of relativistic distant particles at Planck energy can be derived. A first comparison is made with recent observations for Hubble parameter in redshift-dependence in early-type galaxies. We find that LIV has two types of contributions to the time of flight delay Δ t comparable with that observations. Although the wrong OPERA measurement on faster-than-light muon neutrino anomaly, Δ t, and the relative change in the speed of muon neutrino Δ v in dependence on redshift z turn to be wrong, we utilize its main features to estimate Δ v. Accordingly, the results could not be interpreted as LIV. A third comparison is made with the ultra high-energy cosmic rays (UHECR). It is found that an essential ingredient of the approach combining string theory, loop quantum gravity, black hole physics and doubly spacial relativity and the one assuming a perturbative departure from exact Lorentz invariance. Fixing the sensitivity factor and its energy dependence are essential inputs for a reliable confronting of our calculations to UHECR. The sensitivity factor is related to the special time of flight delay and the time structure of the signal. Furthermore, the upper and lower bounds to the parameter, a that characterizes the generalized uncertainly principle, have to be fixed in related physical systems such as the gamma rays bursts.
ICECUBE NEUTRINOS AND LORENTZ INVARIANCE VIOLATION
Amelino-Camelia, Giovanni; Guetta, D.; Piran, Tsvi
2015-06-20
The IceCube neutrino telescope has found so far no evidence of gamma-ray burst (GRB) neutrinos. We here notice that these results assume the same travel times from source to telescope for neutrinos and photons, an assumption that is challenged by some much-studied pictures of spacetime quantization. We briefly review previous results suggesting that limits on quantum-spacetime effects obtained for photons might not be applicable to neutrinos, and we then observe that the outcome of GRB-neutrino searches could depend strongly on whether one allows for neutrinos to be affected by the minute effects of Lorentz invariance violation (LIV) predicted by some relevant quantum-spacetime models. We discuss some relevant issues using as an illustrative example three neutrinos that were detected by IceCube in good spatial coincidence with GRBs, but hours before the corresponding gamma rays. In general, this could happen if the earlier arrival reflects quantum-spacetime-induced LIV, but, as we stress, some consistency criteria must be enforced in order to properly test such a hypothesis. Our analysis sets the stage for future GRB-neutrino searches that could systematically test the possibility of quantum-spacetime-induced LIV.
Entropy production due to Lorentz invariance violation
NASA Astrophysics Data System (ADS)
Mohammadzadeh, Hosein; Farahmand, Mehrnoosh; Maleki, Mahnaz
2017-07-01
It is generally believed that the concept of the spacetime continuum should be modified for distances as small as the Planck length. This is a length scale at which the spacetime might have a discrete structure and quantum gravity effects are dominant. Presumably, the microscopic fluctuations within the geometry of spacetime should result in an enormous entropy production. In the present work, we look for the effects of Lorentz invariance violation (LIV) in flat and curved backgrounds that can be measured by quantum entanglement and quantum thermodynamic entropies for scalar modes. Our results show that the general behavior of these entropies is the same. We also consider variations of the entropies with respect to LIV and cosmological and field parameters. Using the properties of these entropies, along with detecting the most entangled modes, we extract information about the past existence of LIV, which in turn might be useful in recovering the quantum structure of gravity. Indeed, the occurrence of a peak in the behavior of these entropies for a specific momentum could provide information about the expansion parameters. Moreover, information about the LIV parameter is codified in this peak.
Testing local Lorentz invariance with short-range gravity
NASA Astrophysics Data System (ADS)
Kostelecký, V. Alan; Mewes, Matthew
2017-03-01
The Newton limit of gravity is studied in the presence of Lorentz-violating gravitational operators of arbitrary mass dimension. The linearized modified Einstein equations are obtained and the perturbative solutions are constructed and characterized. We develop a formalism for data analysis in laboratory experiments testing gravity at short range and demonstrate that these tests provide unique sensitivity to deviations from local Lorentz invariance.
Testing local Lorentz invariance with short-range gravity
Kostelecký, V. Alan; Mewes, Matthew
2017-01-10
The Newton limit of gravity is studied in the presence of Lorentz-violating gravitational operators of arbitrary mass dimension. The linearized modified Einstein equations are obtained and the perturbative solutions are constructed and characterized. We develop a formalism for data analysis in laboratory experiments testing gravity at short range and demonstrate that these tests provide unique sensitivity to deviations from local Lorentz invariance.
What do we know about Lorentz invariance?
Tasson, Jay D
2014-06-01
The realization that Planck-scale physics can be tested with existing technology through the search for spacetime-symmetry violation brought about the development of a comprehensive framework, known as the gravitational standard-model extension (SME), for studying deviations from exact Lorentz and CPT symmetry in nature. The development of this framework and its motivation led to an explosion of new tests of Lorentz symmetry over the past decade and to considerable theoretical interest in the subject. This work reviews the key concepts associated with Lorentz and CPT symmetry, the structure of the SME framework, and some recent experimental and theoretical results.
Search for anisotropic Lorentz invariance violation with γ -rays
NASA Astrophysics Data System (ADS)
Kislat, Fabian; Krawczynski, Henric
2015-08-01
While Lorentz invariance, the fundamental symmetry of Einstein's theory of general relativity, has been tested to a great level of detail, grand unified theories that combine gravity with the other three fundamental forces may result in a violation of Lorentz symmetry at the Planck scale. These energies are unattainable experimentally. However, minute deviations from Lorentz invariance may still be present at much lower energies. These deviations can accumulate over large distances, making astrophysical measurements the most sensitive tests of Lorentz symmetry. One effect of Lorentz invariance violation is an energy-dependent photon dispersion of the vacuum resulting in differences of the light travel time from distant objects. The Standard Model Extension (SME) is an effective theory to describe the low-energy behavior of a more fundamental grand unified theory, including Lorentz- and C P T -violating terms. In the SME the Lorentz-violating operators can in part be classified by their mass dimension d , with the lowest order being d =5 . However, measurements of photon polarization have constrained operators with d =5 setting lower limits on the energy at which they become dominant well beyond the Planck scale. On the other hand, these operators also violate C P T , and thus d =6 could be the leading order. In this paper we present constraints on all 25 real coefficients describing anisotropic nonbirefringent Lorentz invariance violation at mass dimension d =6 in the SME. We used Fermi-LAT observations of 25 active galactic nuclei to constrain photon dispersion and combined our results with previously published limits in order to simultaneously constrain all 25 coefficients. This represents the first set of constraints on these coefficients of mass dimension d =6 , whereas previous measurements were only able to constrain linear combinations of all 25 coefficients.
How is Lorentz invariance encoded in the Hamiltonian?
NASA Astrophysics Data System (ADS)
Kajuri, Nirmalya
2016-07-01
One of the disadvantages of the Hamiltonian formulation is that Lorentz invariance is not manifest in the former. Given a Hamiltonian, there is no simple way to check whether it is relativistic or not. One would either have to solve for the equations of motion or calculate the Poisson brackets of the Noether charges to perform such a check. In this paper we show that, for a class of Hamiltonians, it is possible to check Lorentz invariance directly from the Hamiltonian. Our work is particularly useful for theories where the other methods may not be readily available.
Living with ghosts in Lorentz invariant theories
Garriga, Jaume; Vilenkin, Alexander E-mail: vilenkin@cosmos.phy.tufts.edu
2013-01-01
We argue that theories with ghosts may have a long lived vacuum state even if all interactions are Lorentz preserving. In space-time dimension D = 2, we consider the tree level decay rate of the vacuum into ghosts and ordinary particles mediated by non-derivative interactions, showing that this is finite and logarithmically growing in time. For D > 2, the decay rate is divergent unless we assume that the interaction between ordinary matter and the ghost sector is soft in the UV, so that it can be described in terms of non-local form factors rather than point-like vertices. We provide an example of a nonlocal gravitational-strength interaction between the two sectors, which appears to satisfy all observational constraints.
Restrictions from Lorentz invariance violation on cosmic ray propagation
NASA Astrophysics Data System (ADS)
Martínez-Huerta, H.; Pérez-Lorenzana, A.
2017-03-01
Lorentz invariance violation introduced as a generic modification to particle dispersion relations is used to study high energy cosmic ray attenuation processes. It is shown to reproduce the same physical effects for vacuum Cherenkov radiation, as in some particular models with spontaneous breaking of Lorentz symmetry. This approximation is also implemented for the study of photon decay in vacuum, where stringent limits to the violation scale are derived from the direct observation of very high energy cosmic ray photon events on gamma telescopes. Photo production processes by cosmic ray primaries on photon background are also addressed, to show that Lorentz violation may turn off this attenuation process at energies above a well-defined secondary threshold.
Quantum gravity and Lorentz invariance violation in the standard model.
Alfaro, Jorge
2005-06-10
The most important problem of fundamental physics is the quantization of the gravitational field. A main difficulty is the lack of available experimental tests that discriminate among the theories proposed to quantize gravity. Recently, Lorentz invariance violation by quantum gravity (QG) has been the source of growing interest. However, the predictions depend on an ad hoc hypothesis and too many arbitrary parameters. Here we show that the standard model itself contains tiny Lorentz invariance violation terms coming from QG. All terms depend on one arbitrary parameter alpha that sets the scale of QG effects. This parameter can be estimated using data from the ultrahigh energy cosmic ray spectrum to be |alpha|< approximately 10(-22)-10(-23).
High Energy Astrophysics Tests of Lorentz Invariance Violation
NASA Technical Reports Server (NTRS)
Stecker, F. W.
2004-01-01
Observations of the multi-TeV spectra of the Mkn 501 and other nearby BL Lac objects exhibit the high energy cutoffs predicted to be the result of intergalactic annihilation interactions, primarily with IR photons having a flux level as determined by various astronomical observations. After correcting for such intergalactic absorption, these spectra can be explained within the framework of synchrotron self-Compton emission models. Stecker and Glashow have shown that the existence of this annihilation via electron-positron pair production puts strong constraints on Lorentz invariance violation. Such constraints have important implications for some quantum gravity and large extra dimension models. A much smaller amount of Lorentz invariance violation has potential implications for understanding the spectra of ultrahigh energy cosmic rays.
Lorentz invariant relative velocity and relativistic binary collisions
NASA Astrophysics Data System (ADS)
Cannoni, Mirco
2017-01-01
This paper reviews the concept of Lorentz invariant relative velocity that is often misunderstood or unknown in high energy physics literature. The properties of the relative velocity allow to formulate the invariant flux and cross-section without recurring to nonphysical velocities or any assumption about the reference frame. Applications such as the luminosity of a collider, the use as kinematic variable, and the statistical theory of collisions in a relativistic classical gas are reviewed. It is emphasized how the hyperbolic properties of the velocity space explain the peculiarities of relativistic scattering.
Lorentz-invariant formulation of Cherenkov radiation by tachyons
NASA Technical Reports Server (NTRS)
Jones, F. C.
1972-01-01
Previous treatments of Cherenkov radiation, electromagnetic and gravitational, by tachyons were in error because the prescription employed to cut off the divergent integral over frequency is not a Lorentz invariant procedure. The resulting equation of motion for the tachyon is therefore not covariant. The proper procedure requires an extended, deformable distribution of charge or mass and yields a particularly simple form for the tachyon's world line, one that could be deduced from simple invariance considerations. It is shown that Cherenkov radiation by tachyons implys their ultimate annihilation with an antitachyon and demonstrates a disturbing property of tachyons, namely the impossibility of specifying arbitrary Cauchy data even in a purely classical theory.
Testing Lorentz invariance of dark matter with satellite galaxies
NASA Astrophysics Data System (ADS)
Bettoni, Dario; Nusser, Adi; Blas, Diego; Sibiryakov, Sergey
2017-05-01
We develop the framework for testing Lorentz invariance in the dark matter sector using galactic dynamics. We consider a Lorentz violating (LV) vector field acting on the dark matter component of a satellite galaxy orbiting in a host halo. We introduce a numerical model for the dynamics of satellites in a galactic halo and for a galaxy in a rich cluster to explore observational consequences of such an LV field. The orbital motion of a satellite excites a time dependent LV force which greatly affects its internal dynamics. Our analysis points out key observational signatures which serve as probes of LV forces. These include modifications to the line of sight velocity dispersion, mass profiles and shapes of satellites. With future data and a more detailed modeling these signatures can be exploited to constrain a new region of the parameter space describing the LV in the dark matter sector.
Discussion on Lorentz invariance violation of noncommutative field theory and neutrino oscillation
NASA Astrophysics Data System (ADS)
Luo, Cui-Bai; Shi, Song; Du, Yi-Lun; Wang, Yong-Long; Zong, Hong-Shi
2017-03-01
Depending on deformed canonical anticommutation relations, massless neutrino oscillation based on Lorentz invariance violation in noncommutative field theory is discussed. It is found that the previous studies about massless neutrino oscillation within deformed canonical anticommutation relations should satisfy the condition of new Moyal product and new nonstandard commutation relations. Furthermore, comparing the Lorentz invariant violation parameters A in the previous studies with new Moyal product and new nonstandard commutation relations, we find that the orders of magnitude of noncommutative parameters (Lorentz invariant violation parameters A) is not self-consistent. This inconsistency means that the previous studies of Lorentz invariance violation in noncommutative field theory may not naturally explain massless neutrino oscillation. In other words, it should be impossible to explain neutrino oscillation by Lorentz invariance violation in noncommutative field theory. This conclusion is supported by the latest atmospheric neutrinos experimental results from the super-Kamiokande Collaboration, which show that no evidence of Lorentz invariance violation on atmospheric neutrinos was observed.
A test of local Lorentz invariance with Compton scattering asymmetry
Mohanmurthy, Prajwal; Narayan, Amrendra; Dutta, Dipangkar
2016-12-14
Here, we report on a measurement of the constancy and anisotropy of the speed of light relative to the electrons in photon-electron scattering. We also used the Compton scattering asymmetry measured by the new Compton polarimeter in Hall~C at Jefferson Lab to test for deviations from unity of the vacuum refractive index (more » $n$). For photon energies in the range of 9 - 46 MeV, we obtain a new limit of $$1-n < 1.4 \\times 10^{-8}$$. In addition, the absence of sidereal variation over the six month period of the measurement constrains any anisotropies in the speed of light. These constitute the first study of Lorentz invariance using Compton asymmetry. Within the minimal standard model extension framework, our result yield limits on the photon and electron coefficients $$\\tilde{\\kappa}_{0^+}^{YZ}, c_{TX}, \\tilde{\\kappa}_{0^+}^{ZX}$$, and $$c_{TY}$$. Though, these limits are several orders of magnitude larger than the current best limits, they demonstrate the feasibility of using Compton asymmetry for tests of Lorentz invariance. For future parity violating electron scattering experiments at Jefferson Lab we will use higher energy electrons enabling better constraints.« less
A test of local Lorentz invariance with Compton scattering asymmetry
Mohanmurthy, Prajwal; Narayan, Amrendra; Dutta, Dipangkar
2016-12-14
Here, we report on a measurement of the constancy and anisotropy of the speed of light relative to the electrons in photon-electron scattering. We also used the Compton scattering asymmetry measured by the new Compton polarimeter in Hall~C at Jefferson Lab to test for deviations from unity of the vacuum refractive index ($n$). For photon energies in the range of 9 - 46 MeV, we obtain a new limit of $1-n < 1.4 \\times 10^{-8}$. In addition, the absence of sidereal variation over the six month period of the measurement constrains any anisotropies in the speed of light. These constitute the first study of Lorentz invariance using Compton asymmetry. Within the minimal standard model extension framework, our result yield limits on the photon and electron coefficients $\\tilde{\\kappa}_{0^+}^{YZ}, c_{TX}, \\tilde{\\kappa}_{0^+}^{ZX}$, and $c_{TY}$. Though, these limits are several orders of magnitude larger than the current best limits, they demonstrate the feasibility of using Compton asymmetry for tests of Lorentz invariance. For future parity violating electron scattering experiments at Jefferson Lab we will use higher energy electrons enabling better constraints.
Tests of Lorentz invariance using a microwave resonator.
Wolf, Peter; Bize, Sébastien; Clairon, André; Luiten, André N; Santarelli, Giorgio; Tobar, Michael E
2003-02-14
The frequencies of a cryogenic sapphire oscillator and a hydrogen maser are compared to set new constraints on a possible violation of Lorentz invariance. We determine the variation of the oscillator frequency as a function of its orientation (Michelson-Morley test) and of its velocity (Kennedy-Thorndike test) with respect to a preferred frame candidate. We constrain the corresponding parameters of the Mansouri and Sexl test theory to delta-beta + 1/2 = (1.5+/-4.2) x 10(-9) and beta-alpha - 1= (-3.1+/-6.9) x 10(-7) which is of the same order as the best previous result for the former and represents a 30-fold improvement for the latter.
Test of Lorentz Invariance with Spin Precession of Ultracold Neutrons
Altarev, I.; Gutsmiedl, E.; Baker, C. A.; Iaydjiev, P.; Ivanov, S. N.; Ban, G.; Lefort, T.; Naviliat-Cuncic, O.; Quemener, G.; Bodek, K.; Kistryn, S.; Zejma, J.; Daum, M.; Henneck, R.; Kirch, K.; Knecht, A.; Lauss, B.; Mtchedlishvili, A.; Petzoldt, G.
2009-08-21
A clock comparison experiment, analyzing the ratio of spin precession frequencies of stored ultracold neutrons and {sup 199}Hg atoms, is reported. No daily variation of this ratio could be found, from which is set an upper limit on the Lorentz invariance violating cosmic anisotropy field b{sub perpendicular}<2x10{sup -20} eV (95% C.L.). This is the first limit for the free neutron. This result is also interpreted as a direct limit on the gravitational dipole moment of the neutron |g{sub n}|<0.3 eV/c{sup 2} m from a spin-dependent interaction with the Sun. Analyzing the gravitational interaction with the Earth, based on previous data, yields a more stringent limit |g{sub n}|<3x10{sup -4} eV/c{sup 2} m.
Lorentz invariance and quantum gravity: an additional fine-tuning problem?
Collins, John; Perez, Alejandro; Sudarsky, Daniel; Urrutia, Luis; Vucetich, Héctor
2004-11-05
Trying to combine standard quantum field theories with gravity leads to a breakdown of the usual structure of space time at around the Planck length, 1.6x10(-35) m, with possible violations of Lorentz invariance. Calculations of preferred-frame effects in quantum gravity have further motivated high precision searches for Lorentz violation. Here, we explain that combining known elementary particle interactions with a Planck-scale preferred frame gives rise to Lorentz violation at the percent level, some 20 orders of magnitude higher than earlier estimates, unless the bare parameters of the theory are unnaturally strongly fine tuned. Therefore an important task is not just the improvement of the precision of searches for violations of Lorentz invariance, but also the search for theoretical mechanisms for automatically preserving Lorentz invariance.
A test of local Lorentz invariance with Compton scattering asymmetry
NASA Astrophysics Data System (ADS)
Mohanmurthy, Prajwal; Narayan, Amrendra; Dutta, Dipangkar
2016-11-01
We report on a measurement of the constancy and anisotropy of the speed of light relative to the electrons in photon-electron scattering. We used the Compton scattering asymmetry measured by the new Compton polarimeter in Hall C at Jefferson Lab (JLab) to test for deviations from unity of the vacuum refractive index (n). For photon energies in the range of 9-46 MeV, we obtain a new limit of 1 - n < 1.4 × 10-8. In addition, the absence of sidereal variation over the six-month period of the measurement constrains any anisotropies in the speed of light. These constitute the first study of Lorentz invariance (LI) using Compton asymmetry. Within the minimal Standard Model extension (MSME) framework, our result yield limits on the photon and electron coefficients κ˜0+Y Z, cTX, κ˜0+ZX and cTY. Although these limits are several orders of magnitude larger than the current best limits, they demonstrate the feasibility of using Compton asymmetry for tests of LI. Future parity-violating electron-scattering experiments at JLab will use higher energy electrons enabling better constraints.
Testing Lorentz Invariance with Laser-Cooled Cesium Atomic Frequency Standards
NASA Technical Reports Server (NTRS)
Klipstein, William M.
2004-01-01
This slide presentation reviews the Lorentz invariance testing during the proposed PARCS experiment. It includes information on the primary atomic reference clock in space (PARCS), cesium, laser cooling, and the vision for the future.
NASA Astrophysics Data System (ADS)
Rubtsov, Grigory; Satunin, Petr; Sibiryakov, Sergey
2017-05-01
Parameterizing hypothetical violation of Lorentz invariance at high energies using the framework of effective quantum field theory, we discuss its effect on the formation of atmospheric showers by very-high-energy gamma rays. In the scenario where Lorentz invariance violation leads to a decrease of the photon velocity with energy the formation of the showers is suppressed compared to the Lorentz invariant case. Absence of such suppression in the high-energy part of spectrum of the Crab nebula measured independently by HEGRA and H.E.S.S. collaborations is used to set lower bounds on the energy scale of Lorentz invariance violation. These bounds are competitive with the strongest existing constraints obtained from timing of variable astrophysical sources and the absorption of TeV photons on the extragalactic background light. They will be further improved by the next generation of multi-TeV gamma-ray observatories.
Two-pion exchange NN potential from Lorentz-invariant $\\chi$EFT
Higa, Renato; Robilotta, Manoel; da Rocha, Carlos A
2006-10-12
We outline the progress made in the past five years by the Sao Paulo group in the development of a two-pion exchange nucleon-nucleon potential within a Lorentz-invariant framework of (baryon) chiral perturbation theory.
Testing Lorentz Invariance with Laser-Cooled Cesium Atomic Frequency Standards
NASA Technical Reports Server (NTRS)
Klipstein, William M.
2004-01-01
This slide presentation reviews the Lorentz invariance testing during the proposed PARCS experiment. It includes information on the primary atomic reference clock in space (PARCS), cesium, laser cooling, and the vision for the future.
Search for a proposed signature of Lorentz-invariant spacetime granularity
NASA Astrophysics Data System (ADS)
Terrano, W. A.; Heckel, B. R.; Adelberger, E. G.
2011-07-01
We used a rotating torsion pendulum containing ≈1023 polarized electrons placed in an orientable quadrupole source to constrain Bonder and Sudarsky's quantum-gravity effect based on a Lorentz-invariant spacetime granularity model proposed by Corichi and Sudarsky. Our null results constrain the model's free parameters 13 orders of magnitude more tightly than those Bonder and Sudarsky obtained by reinterpreting the data from a previous polarized neutron experiment that was designed to test Lorentz invariance.
Modifications of the Lorentz Force Law Invariant under Galilean Transformations
NASA Astrophysics Data System (ADS)
Su, Ching-Chuan
2001-03-01
Postulate that the electromagnetic force exerted on an effector of charge q and velocity ve due to mobile source particles of charge density ρ v and velocity vs is [ F(r,t)=q -nabla breveΦ(r,t)-( frac partial partial tbreveA(r,t)) _e , ] where the augmented scalar potential breveΦ( r,t)=int (1+v _se^2/2c^2) ρ _v( r^' ,t^' )Gdv^' , the augmented vector potential breveA=c-2int v_seρ _vGdv^' , t^' =t-R/c, R=|r-r^' |, G=1/4π ɛ _0R, v_se=v_s-v_e, r ^' , r, v_s, and ve are referred to the local-ether frame [1], and (partial /partial t)e to the effector frame. Note that the proposed force is Galilean invariant. Consider the ordinary case where the source particles drift in a matrix (such as a metal wire) of charge density ρ m and velocity v_m. Under the low-speed condition of low effector speed and very low drift speed ( v_sm<< v_em<< c), it can be shown that breveΦ=Φ -v _em\\cdot A, breveA=A, and hence the force becomes F =q( E+v_em× B), where E=-nabla Φ -(partial A/partial t)_m, B=nabla × A, Φ =int ρ _nGdv^' , A=c-2int J_nGdv^' , ρ _n=ρ _v+ρ _m, J_n=v_smρ _v, and (partial /partial t)m is referred to the matrix frame. This equation presents modifications of the Lorentz force law. The fundamental modifications are that the current density in A, the time derivative applied to A, and the effector velocity before B are all referred to the matrix frame and the propagation delay to the local-ether frame. However, under the low-speed condition, the proposed Galilean model can agree with the Lorentz force law, if the latter is observed in the matrix frame as done in common practice. [1] C.C. Su, 2000 IEEE Antennas Propagat. Soc. Int. Symp. Dig., p. 1570.
Conditions for Lorentz-invariant superluminal information transfer without signaling
NASA Astrophysics Data System (ADS)
Grössing, G.; Fussy, S.; Mesa Pascasio, J.; Schwabl, H.
2016-03-01
We understand emergent quantum mechanics in the sense that quantum mechanics describes processes of physical emergence relating an assumed sub-quantum physics to macroscopic boundary conditions. The latter can be shown to entail top-down causation, in addition to usual bottom-up scenarios. With this example it is demonstrated that definitions of “realism” in the literature are simply too restrictive. A prevailing manner to define realism in quantum mechanics is in terms of pre-determination independent of the measurement. With our counter-example, which actually is ubiquitous in emergent, or self-organizing, systems, we argue for realism without pre-determination. We refer to earlier results of our group showing how the guiding equation of the de Broglie-Bohm interpretation can be derived from a theory with classical ingredients only. Essentially, this corresponds to a “quantum mechanics without wave functions” in ordinary 3-space, albeit with nonlocal correlations. This, then, leads to the central question of how to deal with the nonlocality problem in a relativistic setting. We here show that a basic argument discussing the allegedly paradox time ordering of events in EPR-type two-particle experiments falls short of taking into account the contextuality of the experimental setup. Consequently, we then discuss under which circumstances (i.e. physical premises) superluminal information transfer (but not signaling) may be compatible with a Lorentz-invariant theory. Finally, we argue that the impossibility of superluminal signaling - despite the presence of superluminal information transfer - is not the result of some sort of conspiracy (á la “Nature likes to hide”), but the consequence of the impossibility to exactly reproduce in repeated experimental runs a state's preparation, or of the no-cloning theorem, respectively.
Testing Lorentz invariance using an odd-parity asymmetric optical resonator
Baynes, Fred N.; Luiten, Andre N.; Tobar, Michael E.
2011-10-15
We present the first experimental test of Lorentz invariance using the frequency difference between counter-propagating modes in an asymmetric odd-parity optical resonator. This type of test is {approx}10{sup 4} more sensitive to odd-parity and isotropic (scalar) violations of Lorentz invariance than equivalent conventional even-parity experiments due to the asymmetry of the optical resonator. The disadvantages of odd-parity resonators have been negated by the use of counter-propagating modes, delivering a high level of immunity to environmental fluctuations. With a nonrotating experiment our result limits the isotropic Lorentz violating parameter {kappa}-tilde{sub tr} to 3.4{+-}6.2x10{sup -9}, the best reported constraint from direct measurements. Using this technique the bounds on odd-parity and scalar violations of Lorentz invariance can be improved by many orders of magnitude.
Enhanced sensitivity to Lorentz invariance violations in short-range gravity experiments
NASA Astrophysics Data System (ADS)
Shao, Cheng-Gang; Chen, Ya-Fen; Tan, Yu-Jie; Luo, Jun; Yang, Shan-Qing; Tobar, Michael Edmund
2016-11-01
Recently, first limits on putative Lorentz invariance violation coefficients in the pure gravity sector were determined by the reanalysis of short-range gravity experiments. Such experiments search for new physics at sidereal frequencies. They are not, however, designed to optimize the signal strength of a Lorentz invariance violation force; in fact the Lorentz violating signal is suppressed in the planar test mass geometry employed in those experiments. We describe a short-range torsion pendulum experiment with enhanced sensitivity to possible Lorentz violating signals. A periodic, striped test mass geometry is used to augment the signal. Careful arrangement of the phases of the striped patterns on opposite ends of the pendulum further enhances the signal while simultaneously suppressing the Newtonian background.
Cosmological constraints on deviations from Lorentz invariance in gravity and dark matter
Audren, B.; Lesgourgues, J.; Sibiryakov, S.; Ivanov, M.M. E-mail: diego.blas@cern.ch E-mail: Julien.Lesgourgues@cern.ch
2015-03-01
We consider a scenario where local Lorentz invariance is violated by the existence of a preferred time direction at every space-time point. This scenario can arise in the context of quantum gravity and its description at low energies contains a unit time-like vector field which parameterizes the preferred direction. The particle physics tests of Lorentz invariance preclude a direct coupling of this vector to the fields of the Standard Model, but do not bear implications for dark matter. We discuss how the presence of this vector and its possible coupling to dark matter affect the evolution of the Universe. At the level of homogeneous cosmology the only effect of Lorentz invariance violation is a rescaling of the expansion rate. The physics is richer at the level of perturbations. We identify three effects crucial for observations: the rescaling of the matter contribution to the Poisson equation, the appearance of an extra contribution to the anisotropic stress and the scale-dependent enhancement of dark matter clustering. These effects result in distinctive features in the power spectra of the CMB and density fluctuations. Making use of the data from Planck and WiggleZ we obtain the most stringent cosmological constraints to date on departures from Lorentz symmetry. Our analysis provides the first direct bounds on deviations from Lorentz invariance in the dark matter sector.
Tests of Lorentz and CPT Invariance in Space
NASA Technical Reports Server (NTRS)
Mewes, Matthew
2003-01-01
I give a brief overview of recent work concerning possible signals of Lorentz violation in sensitive clock-based experiments in space. The systems under consideration include atomic clocks and electromagnetic resonators of the type planned for flight on the International Space Station.
High Energy Astrophysics Tests of Lorentz Invariance Violation
NASA Technical Reports Server (NTRS)
Stecker, Floyd W.
2004-01-01
Observations of the multi-TeV spectra of the nearby BL Lac objects Mkn 421 and Mkn 501 exhibit the high energy cutoffs predicted to be the result of intergalactic annihilation interactions, primarily with IR photons having a flux level as determined by various astronomical observations. After correcting for such intergalactic absorption, these spectra can be explained within the framework of synchrotron self-Compton emission models. Stecker & Glashow have shown that the existence of this annihilation via electron-positron pair production puts strong constraints on Lorentz violation. We will show that such constraints have important implications for some quantum gravity models and large extra dimension models. We will also discuss the potentially important effects of a smaller Lorentz violation which is consistent with these constraints on the propagation and spectra of ultrahigh energy cosmic rays.
Lorentz-invariant actions for chiral p-forms
Pasti, P.; Sorokin, D.; Tonin, M.
1997-05-01
We demonstrate how a Lorentz-covariant formulation of the chiral p-form model in D=2(p+1) containing infinitely many auxiliary fields is related to a Lorentz-covariant formulation with only one auxiliary scalar field entering a chiral p-form action in a nonpolynomial way. The latter can be regarded as a consistent Lorentz-covariant truncation of the former. We make the Hamiltonian analysis of the model based on the nonpolynomial action and show that the Dirac constraints have a simple form and are all first class. In contrast with the Siegel model the constraints are not the square of second-class constraints. The canonical Hamiltonian is quadratic and determines the energy of a single chiral p-form. In the case of D=2 chiral scalars the constraint can be improved by use of a {open_quotes}twisting{close_quotes} procedure (without the loss of the property to be first class) in such a way that the central charge of the quantum constraint algebra is zero. This points to the possible absence of an anomaly in an appropriate quantum version of the model. {copyright} {ital 1997} {ital The American Physical Society}
On existence of a possible Lorentz invariant modified gravity in Weitzenböck spacetime
NASA Astrophysics Data System (ADS)
Momeni, Davood; Myrzakulov, Ratbay
2015-11-01
Modified gravity which was constructed by torsion scalar T, namely f(T) doesn't respect Lorentz symmetry. As an attempt to make a new torsion based modified gravity with Lorentz invariance, recently f(T,B) introduced where B=2nabla_{μ}T^{μ} (Bahamonde et al. in arXiv:1508.05120, 2015). We would argue, even when theory is constructed and done in a self-consistent form, but if we handle them properly, we observe that there is no Lorentz invariant teleparallel equivalent of f(R) gravity. All we found is that the f(R) gravity in which R must be computed in Weitzenböck spacetime, using Weitzenböck's connection, nor Levi-Civita connections is the only possible Lorentz invariant type of modified gravity. Consequently, f(T) gravity can not obey Lorentz symmetry not only in its orthodoxica form but even in this new framework f(T,B).
High Energy Astrophysics Tests of Lorentz Invariance and Quantum Gravity Models
NASA Technical Reports Server (NTRS)
Stecker, Floyd W.
2011-01-01
High-energy astrophysics observations provide the best possibilities to detect a very small violation of Lorentz invariance such as may be related to the structure of space-time near the Planck scale of approximately 10-35 m. I will discuss here the possible signatures of Lorentz invariance violation (LIV) from observations of the spectra, polarization, and timing of gamma-rays from active galactic nuclei and gamma-ray bursts. Other sensitive tests are provided by observations ofthe spectra of ultrahigh energy cosmic rays and neutrinos. Using the latest data from the Pierre Auger Observatory one can already derive an upper limit of 4.5 x 10(exp -23) to the amount of LIV at a proton Lorentz factor of -2 x 10(exp 11). This result has fundamental implications for quantum gravity models. I will also discuss the possibilities of using more sensitive space based detection techniques to improve searches for LIV in the future.
Gamma-Ray, Cosmic Ray and Neutrino Tests of Lorentz Invariance and Quantum Gravity Models
NASA Technical Reports Server (NTRS)
Stecker, Floyd
2011-01-01
High-energy astrophysics observations provide the best possibilities to detect a very small violation of Lorentz invariance such as may be related to the structure of space-time near the Planck scale of approximately 10(exp -35) m. I will discuss here the possible signatures of Lorentz invariance violation (LIV) from observations of the spectra, polarization, and timing of gamma-rays from active galactic nuclei and gamma-ray bursts. Other sensitive tests are provided by observations of the spectra of ultrahigh energy cosmic rays and neutrinos. Using the latest data from the Pierre Auger Observatory one can already derive an upper limit of 4.5 x 10(exp -23) to the amount of LIV of at a proton Lorentz factor of approximately 2 x 10(exp 11). This result has fundamental implications for quantum gravity models. I will also discuss the possibilities of using more sensitive space based detection techniques to improve searches for LIV in the future.
New test of local Lorentz invariance using a 21Ne-Rb-K comagnetometer.
Smiciklas, M; Brown, J M; Cheuk, L W; Smullin, S J; Romalis, M V
2011-10-21
We develop a new comagnetometer using (21)Ne atoms with nuclear spin I=3/2 and Rb atoms polarized by spin exchange with K atoms to search for tensor interactions that violate local Lorentz invariance. We frequently reverse the orientation of the experiment and search for signals at the first and second harmonics of the sidereal frequency. We constrain 4 of the 5 spatial Lorentz-violating coefficients c(jk)(n) that parametrize anisotropy of the maximum attainable velocity of a neutron at a level of 10(-29), improving previous limits by 2 to 4 orders of magnitude and placing the most stringent constraint on deviations from local Lorentz invariance. © 2011 American Physical Society
Maccione, Luca; Liberati, Stefano; Mattingly, David M. E-mail: liberati@sissa.it
2013-03-01
Recently there has been a renewed activity in the physics of violations of Lorentz invariance in the neutrino sector. Flavor dependent Lorentz violation, which generically changes the pattern of neutrino oscillations, is extremely tightly constrained by oscillation experiments. Flavor independent Lorentz violation, which does not introduce new oscillation phenomena, is much more weakly constrained with constraints coming from time of flight and anomalous threshold analyses. We use a simplified rotationally invariant model to investigate the effects of finite baselines and energy dependent dispersion on anomalous reaction rates in long baseline experiments and show numerically that anomalous reactions do not necessarily cut off the spectrum quite as sharply as currently assumed. We also present a revised analysis of how anomalous reactions can be used to cast constraints from the observed atmospheric high energy neutrinos and the expected cosmogenic ones.
Photon emission and decay from generic Lorentz invariance violation
NASA Astrophysics Data System (ADS)
Martínez-Huerta, H.; Pérez-Lorenzana, A.
2017-06-01
One of the most studied approaches in phenomenology to introduce the breaking of Lorentz symmetry is the generic approach. This consist on the modification of the free particle dispersion relation by the addition of an extra power law term of order n on energy or momentum. Using this approach in the photon sector, we have calculated the generic rates for vacuum Cherenkov radiation and photon decay, for any order n, at leading order. Explicit results for the decay and emission rates for the lowest values of n are also presented.
Seven Experiments to Test the Local Lorentz Invariance of c
NASA Technical Reports Server (NTRS)
Gezari, Daniel Y.
2005-01-01
The speed of light has never been measured directly with a moving detector to test the fundamental assertion of special relativity that c is invariant to motion of the observer. Seven simple experiments are proposed, four of which could test the invariance of c to motion of the detector. Three other observations of moving sources could test Einstein s second postulate and the relativity of stellar aberration. There are lingering concerns that the speed of light may depend on the motion of the observer, after all. This issue can now be resolved by experiment.
Unusual high-energy phenomenology of Lorentz-invariant noncommutative field theories
Carone, Christopher D.; Kwee, Herry J.
2006-05-01
It has been suggested that one may construct a Lorentz-invariant noncommutative field theory by extending the coordinate algebra to additional, fictitious coordinates that transform nontrivially under the Lorentz group. Integration over these coordinates in the action produces a four-dimensional effective theory with Lorentz invariance intact. Previous applications of this approach, in particular, to a specific construction of noncommutative QED, have been studied only in a low-momentum approximation. Here we discuss Lorentz-invariant field theories in which the relevant physics can be studied without requiring an expansion in the inverse scale of noncommutativity. Qualitatively, we find that tree-level scattering cross sections are dramatically suppressed as the center-of-mass energy exceeds the scale of noncommutativity, that cross sections that are isotropic in the commutative limit can develop a pronounced angular dependence, and that nonrelativistic potentials (for example, the Coloumb potential) become nonsingular at the origin. We consider a number of processes in noncommutative QED that may be studied at a future linear collider. We also give an example of scattering via a four-fermion operator in which the noncommutative modifications of the interaction can unitarize the tree-level amplitude, without requiring any other new physics in the ultraviolet.
Diverging light pulses in vacuum: Lorentz-invariant mass and mean propagation speed
NASA Astrophysics Data System (ADS)
Fedorov, M. V.; Vintskevich, S. V.
2017-03-01
We show that the concept of the Lorentz-invariant mass of groups of particles can be applied to light pulses consisting of very large but finite numbers of noncollinear photons. Explicit expressions are found for the invariant mass of this manifold of photons for the case of diverging Gaussian light pulses propagating in vacuum. As the found invariant mass is finite, the light pulses propagate in vacuum with a speed somewhat smaller than the light speed. A small difference between the light speed and the beam-propagation velocity is found to be directly related to the invariant mass of a pulse. Focusing and/or defocusing light pulses is shown to strengthen the effect in which the pulse slows down while the pulse invariant mass increases. A scheme for measuring these quantities experimentally is proposed and discussed.
Lorentz invariance violation as an explanation of the muon excess in Auger data
NASA Astrophysics Data System (ADS)
Tomar, Gaurav
2017-05-01
The Auger Collaboration has observed the number of muons, which is higher than its prediction by existing hadronic interaction models. We explain this excess of muons by using Lorentz invariance violation (LIV) in the photon sector. As an outcome of Lorentz invariance violation, the dispersion relation of the photon gets modified, which we use for the calculation of π0 decay width. In the Auger data of primary energy 1 09.8
Search for violation of Lorentz invariance in top quark pair production and decay.
Abazov, V M; Abbott, B; Acharya, B S; Adams, M; Adams, T; Alexeev, G D; Alkhazov, G; Alton, A; Alverson, G; Aoki, M; Askew, A; Atkins, S; Augsten, K; Avila, C; Badaud, F; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, S; Barberis, E; Baringer, P; Barreto, J; Bartlett, J F; Bassler, U; Bazterra, V; Bean, A; Begalli, M; Bellantoni, L; Berger, M S; Beri, S B; Bernardi, G; Bernhard, R; Bertram, I; Besançon, M; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatia, S; Bhatnagar, V; Blazey, G; Blessing, S; Bloom, K; Boehnlein, A; Boline, D; Boos, E E; Borissov, G; Bose, T; Brandt, A; Brandt, O; Brock, R; Brooijmans, G; Bross, A; Brown, D; Brown, J; Bu, X B; Buehler, M; Buescher, V; Bunichev, V; Burdin, S; Buszello, C P; Camacho-Pérez, E; Casey, B C K; Castilla-Valdez, H; Caughron, S; Chakrabarti, S; Chakraborty, D; Chan, K M; Chandra, A; Chapon, E; Chen, G; Chevalier-Théry, S; Cho, D K; Cho, S W; Choi, S; Choudhary, B; Cihangir, S; Claes, D; Clutter, J; Cooke, M; Cooper, W E; Corcoran, M; Couderc, F; Cousinou, M-C; Croc, A; Cutts, D; Das, A; Davies, G; de Jong, S J; De la Cruz-Burelo, E; Déliot, F; Demina, R; Denisov, D; Denisov, S P; Desai, S; Deterre, C; DeVaughan, K; Diehl, H T; Diesburg, M; Ding, P F; Dominguez, A; Dubey, A; Dudko, L V; Duggan, D; Duperrin, A; Dutt, S; Dyshkant, A; Eads, M; Edmunds, D; Ellison, J; Elvira, V D; Enari, Y; Evans, H; Evdokimov, A; Evdokimov, V N; Facini, G; Feng, L; Ferbel, T; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Fortner, M; Fox, H; Fuess, S; Garcia-Bellido, A; García-González, J A; García-Guerra, G A; Gavrilov, V; Gay, P; Geng, W; Gerbaudo, D; Gerber, C E; Gershtein, Y; Ginther, G; Golovanov, G; Goussiou, A; Grannis, P D; Greder, S; Greenlee, H; Grenier, G; Gris, Ph; Grivaz, J-F; Grohsjean, A; Grünendahl, S; Grünewald, M W; Guillemin, T; Gutierrez, G; Gutierrez, P; Haas, A; Hagopian, S; Haley, J; Han, L; Harder, K; Harel, A; Hauptman, J M; Hays, J; Head, T; Hebbeker, T; Hedin, D; Hegab, H; Heinson, A P; Heintz, U; Hensel, C; Heredia-De la Cruz, I; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hoang, T; Hobbs, J D; Hoeneisen, B; Hohlfeld, M; Howley, I; Hubacek, Z; Hynek, V; Iashvili, I; Ilchenko, Y; Illingworth, R; Ito, A S; Jabeen, S; Jaffré, M; Jayasinghe, A; Jesik, R; Johns, K; Johnson, E; Johnson, M; Jonckheere, A; Jonsson, P; Joshi, J; Jung, A W; Juste, A; Kaadze, K; Kajfasz, E; Karmanov, D; Kasper, P A; Katsanos, I; Kehoe, R; Kermiche, S; Khalatyan, N; Khanov, A; Kharchilava, A; Kharzheev, Y N; Kiselevich, I; Kohli, J M; Kostelecký, V A; Kozelov, A V; Kraus, J; Kulikov, S; Kumar, A; Kupco, A; Kurča, T; Kuzmin, V A; Lammers, S; Landsberg, G; Lebrun, P; Lee, H S; Lee, S W; Lee, W M; Lellouch, J; Li, H; Li, L; Li, Q Z; Lim, J K; Lincoln, D; Linnemann, J; Lipaev, V V; Lipton, R; Liu, H; Liu, Y; Lobodenko, A; Lokajicek, M; Lopes de Sa, R; Lubatti, H J; Luna-Garcia, R; Lyon, A L; Maciel, A K A; Madar, R; Magaña-Villalba, R; Malik, S; Malyshev, V L; Maravin, Y; Martínez-Ortega, J; McCarthy, R; McGivern, C L; Meijer, M M; Melnitchouk, A; Menezes, D; Mercadante, P G; Merkin, M; Meyer, A; Meyer, J; Miconi, F; Mondal, N K; Mulhearn, M; Nagy, E; Naimuddin, M; Narain, M; Nayyar, R; Neal, H A; Negret, J P; Neustroev, P; Nunnemann, T; Obrant, G; Orduna, J; Osman, N; Osta, J; Padilla, M; Pal, A; Parashar, N; Parihar, V; Park, S K; Partridge, R; Parua, N; Patwa, A; Penning, B; Perfilov, M; Peters, Y; Petridis, K; Petrillo, G; Pétroff, P; Pleier, M-A; Podesta-Lerma, P L M; Podstavkov, V M; Popov, A V; Prewitt, M; Price, D; Prokopenko, N; Qian, J; Quadt, A; Quinn, B; Rangel, M S; Ranjan, K; Ratoff, P N; Razumov, I; Renkel, P; Ripp-Baudot, I; Rizatdinova, F; Rominsky, M; Ross, A; Royon, C; Rubinov, P; Ruchti, R; Sajot, G; Salcido, P; Sánchez-Hernández, A; Sanders, M P; Sanghi, B; Santos, A S; Savage, G; Sawyer, L; Scanlon, T; Schamberger, R D; Scheglov, Y; Schellman, H; Schlobohm, S; Schwanenberger, C; Schwienhorst, R; Sekaric, J; Severini, H; Shabalina, E; Shary, V; Shaw, S; Shchukin, A A; Shivpuri, R K; Simak, V; Skubic, P; Slattery, P; Smirnov, D; Smith, K J; Snow, G R; Snow, J; Snyder, S; Söldner-Rembold, S; Sonnenschein, L; Soustruznik, K; Stark, J; Stoyanova, D A; Strauss, M; Stutte, L; Suter, L; Svoisky, P; Takahashi, M; Titov, M; Tokmenin, V V; Tsai, Y-T; Tschann-Grimm, K; Tsybychev, D; Tuchming, B; Tully, C; Uvarov, L; Uvarov, S; Uzunyan, S; Van Kooten, R; van Leeuwen, W M; Varelas, N; Varnes, E W; Vasilyev, I A; Verdier, P; Verkheev, A Y; Vertogradov, L S; Verzocchi, M; Vesterinen, M; Vilanova, D; Vokac, P; Wahl, H D; Wang, M H L S; Warchol, J; Watts, G; Wayne, M; Weichert, J; Welty-Rieger, L; White, A; Whittington, D; Wicke, D; Williams, M R J; Wilson, G W; Wobisch, M; Wood, D R; Wyatt, T R; Xie, Y; Yamada, R; Yang, W-C; Yasuda, T; Yatsunenko, Y A; Ye, W; Ye, Z; Yin, H; Yip, K; Youn, S W; Zennamo, J; Zhao, T; Zhao, T G; Zhou, B; Zhu, J; Zielinski, M; Zieminska, D; Zivkovic, L
2012-06-29
Using data collected with the D0 detector at the Fermilab Tevatron Collider, corresponding to 5.3 fb(-1) of integrated luminosity, we search for violation of Lorentz invariance by examining the tt[over ¯] production cross section in lepton+jets final states. We quantify this violation using the standard-model extension framework, which predicts a dependence of the tt[over ¯] production cross section on sidereal time as the orientation of the detector changes with the rotation of the Earth. Within this framework, we measure components of the matrices (c(Q))(μν33) and (c(U))(μν33) containing coefficients used to parametrize violation of Lorentz invariance in the top quark sector. Within uncertainties, these coefficients are found to be consistent with zero.
Search for Violation of Lorentz Invariance in Top Quark Pair Production and Decay
Abazov V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Alverson, G.; Aoki, M.; Askew, A.; Atkins, S.; Augsten, K.; Avila, C.; Badaud, F.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Barberis, E.; Baringer, P.; Barreto, J.; Bartlett, J. F.; Bassler, U.; Bazterra, V.; Bean, A.; Begalli, M.; Bellantoni, L.; Berger, M. S.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besancon, M.; Beuselinck, R.; Bezzubov, V. A.; Bhat, P. C.; Bhatia, S.; Bhatnagar, V.; Blazey, G.; Blessing, S.; Bloom, K.; Boehnlein, A.; Boline, D.; Boos, E. E.; Borissov, G.; Bose, T.; Brandt, A.; Brandt, O.; Brock, R.; Brooijmans, G.; Bross, A.; Brown, D.; Brown, J.; Bu, X. B.; Buehler, M.; Buescher, V.; Bunichev, V.; Burdin, S.; Buszello, C. P.; Camacho-Perez, E.; Casey, B. C. K.; Castilla-Valdez, H.; Caughron, S.; Chakrabarti, S.; Chakraborty, D.; Chan, K. M.; Chandra, A.; Chapon, E.; Chen, G.; Chevalier-Thery, S.; Cho, D. K.; Cho, S. W.; Choi, S.; Choudhary, B.; Cihangir, S.; Claes, D.; Clutter, J.; Cooke, M.; Cooper, W. E.; Corcoran, M.; Couderc, F.; Cousinou, M. -C.; Croc, A.; Cutts, D.; Das, A.; Davies, G.; de Jong, S. J.; De La Cruz-Burelo, E.; Deliot, F.; Demina, R.; Denisov, D.; Denisov, S. P.; Desai, S.; Deterre, C.; DeVaughan, K.; Diehl, H. T.; Diesburg, M.; Ding, P. F.; Dominguez, A.; Dubey, A.; Dudko, L. V.; Duggan, D.; Duperrin, A.; Dutt, S.; Dyshkant, A.; Eads, M.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Enari, Y.; Evans, H.; Evdokimov, A.; Evdokimov, V. N.; Facini, G.; Feng, L.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Fortner, M.; Fox, H.; Fuess, S.; Garcia-Bellido, A.; Garcia-Gonzalez, J. A.; Garcia-Guerra, G. A.; Gavrilov, V.; Gay, P.; Geng, W.; Gerbaudo, D.; Gerber, C. E.; Gershtein, Y.; Ginther, G.; Golovanov, G.; Goussiou, A.; Grannis, P. D.; Greder, S.; Greenlee, H.; Grenier, G.; Gris, Ph.; Grivaz, J. -F.; Grohsjean, A.; Gruenendahl, S.; Gruenewald, M. W.; Guillemin, T.; Gutierrez, G.; Gutierrez, P.; Haas, A.; Hagopian, S.; Haley, J.; Han, L.; Harder, K.; Harel, A.; Hauptman, J. M.; Hays, J.; Head, T.; Hebbeker, T.; Hedin, D.; Hegab, H.; Heinson, A. P.; Heintz, U.; Hensel, C.; Heredia-De La Cruz, I.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hoang, T.; Hobbs, J. D.; Hoeneisen, B.; Hohlfeld, M.; Howley, I.; Hubacek, Z.; Hynek, V.; Iashvili, I.; Ilchenko, Y.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffre, M.; Jayasinghe, A.; Jesik, R.; Johns, K.; Johnson, E.; Johnson, M.; Jonckheere, A.; Jonsson, P.; Joshi, J.; Jung, A. W.; Juste, A.; Kaadze, K.; Kajfasz, E.; Karmanov, D.; Kasper, P. A.; Katsanos, I.; Kehoe, R.; Kermiche, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. N.; Kiselevich, I.; Kohli, J. M.; Kostelecky, V. A.; Kozelov, A. V.; Kraus, J.; Kulikov, S.; Kumar, A.; Kupco, A.; Kurca, T.; Kuzmin, V. A.; Lammers, S.; Landsberg, G.; Lebrun, P.; Lee, H. S.; Lee, S. W.; Lee, W. M.; Lellouch, J.; Li, H.; Li, L.; Li, Q. Z.; Lim, J. K.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, H.; Liu, Y.; Lobodenko, A.; Lokajicek, M.; de Sa, R. Lopes; Lubatti, H. J.; Luna-Garcia, R.; Lyon, A. L.; Maciel, A. K. A.; Madar, R.; Magana-Villalba, R.; Malik, S.; Malyshev, V. L.; Maravin, Y.; Martinez-Ortega, J.; McCarthy, R.; McGivern, C. L.; Meijer, M. M.; Melnitchouk, A.; Menezes, D.; Mercadante, P. G.; Merkin, M.; et al.
2012-06-27
Using data collected with the D0 detector at the Fermilab Tevatron Collider, corresponding to 5.3 fb{sup -1} of integrated luminosity, we search for violation of Lorentz invariance by examining the t{bar t} production cross section in lepton+jets final states. We quantify this violation using the standard-model extension framework, which predicts a dependence of the t{bar t} production cross section on sidereal time as the orientation of the detector changes with the rotation of the Earth. Within this framework, we measure components of the matrices (c{sub Q}){sub {mu}{nu}33} and (c{sub U}){sub {mu}{nu}33} containing coefficients used to parametrize violation of Lorentz invariance in the top quark sector. Within uncertainties, these coefficients are found to be consistent with zero.
On the assertion that PCT violation implies Lorentz non-invariance
NASA Astrophysics Data System (ADS)
Dütsch, Michael; Gracia-Bondía, José M.
2012-05-01
Out of conviction or expediency, some current research programs (Kostelecký (2008) [1], Kostelecký and Russell (2011) [2], Ferrero and Altschul (2011) [3], Anselmi (2009) [4]) take for granted that "PCT violation implies violation of Lorentz invariance". We point out that this claim (Greenberg (2002) [5]) is still on somewhat shaky ground. In fact, for many years there has been no strengthening of the evidence in this direction. However, using causal perturbation theory, we prove here that when starting with a local PCT-invariant interaction, PCT symmetry can be maintained in the process of renormalization.
Search for Violations of Lorentz Invariance and CPT Symmetry in B_{(s)}^{0} Mixing.
Aaij, R; Abellán Beteta, C; Adeva, B; Adinolfi, M; Ajaltouni, Z; Akar, S; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amerio, S; Amhis, Y; An, L; Anderlini, L; Andreassi, G; Andreotti, M; Andrews, J E; Appleby, R B; Aquines Gutierrez, O; Archilli, F; d'Argent, P; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Baalouch, M; Bachmann, S; Back, J J; Badalov, A; Baesso, C; Baker, S; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Batozskaya, V; Battista, V; Bay, A; Beaucourt, L; Beddow, J; Bedeschi, F; Bediaga, I; Bel, L J; Bellee, V; Belloli, N; Belyaev, I; Ben-Haim, E; Bencivenni, G; Benson, S; Benton, J; Berezhnoy, A; Bernet, R; Bertolin, A; Betti, F; Bettler, M-O; van Beuzekom, M; Bifani, S; Billoir, P; Bird, T; Birnkraut, A; Bizzeti, A; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Bondar, A; Bondar, N; Bonivento, W; Borgheresi, A; Borghi, S; Borisyak, M; Borsato, M; Boubdir, M; Bowcock, T J V; Bowen, E; Bozzi, C; Braun, S; Britsch, M; Britton, T; Brodzicka, J; Buchanan, E; Burr, C; Bursche, A; Buytaert, J; Cadeddu, S; Calabrese, R; Calvi, M; Calvo Gomez, M; Campana, P; Campora Perez, D; Capriotti, L; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carniti, P; Carson, L; Carvalho Akiba, K; Casse, G; Cassina, L; Castillo Garcia, L; Cattaneo, M; Cauet, Ch; Cavallero, G; Cenci, R; Charles, M; Charpentier, Ph; Chatzikonstantinidis, G; Chefdeville, M; Chen, S; Cheung, S-F; Chrzaszcz, M; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coco, V; Cogan, J; Cogneras, E; Cogoni, V; Cojocariu, L; Collazuol, G; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombes, M; Coquereau, S; Corti, G; Corvo, M; Couturier, B; Cowan, G A; Craik, D C; Crocombe, A; Cruz Torres, M; Cunliffe, S; Currie, R; D'Ambrosio, C; Dall'Occo, E; Dalseno, J; David, P N Y; Davis, A; De Aguiar Francisco, O; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Simone, P; Dean, C-T; 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Martinez Vidal, F; Martins Tostes, D; Massacrier, L M; Massafferri, A; Matev, R; Mathad, A; Mathe, Z; Matteuzzi, C; Mauri, A; Maurin, B; Mazurov, A; McCann, M; McCarthy, J; McNab, A; McNulty, R; Meadows, B; Meier, F; Meissner, M; Melnychuk, D; Merk, M; Merli, A; Michielin, E; Milanes, D A; Minard, M-N; Mitzel, D S; Molina Rodriguez, J; Monroy, I A; Monteil, S; Morandin, M; Morawski, P; Mordà, A; Morello, M J; Moron, J; Morris, A B; Mountain, R; Muheim, F; Müller, D; Müller, J; Müller, K; Müller, V; Mussini, M; Muster, B; Naik, P; Nakada, T; Nandakumar, R; Nandi, A; Nasteva, I; Needham, M; Neri, N; Neubert, S; Neufeld, N; Neuner, M; Nguyen, A D; Nguyen-Mau, C; Niess, V; Nieswand, S; Niet, R; Nikitin, N; Nikodem, T; Novoselov, A; O'Hanlon, D P; Oblakowska-Mucha, A; Obraztsov, V; Ogilvy, S; Okhrimenko, O; Oldeman, R; Onderwater, C J G; Osorio Rodrigues, B; Otalora Goicochea, J M; Otto, A; Owen, P; Oyanguren, A; Palano, A; Palombo, F; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Pappalardo, L L; Pappenheimer, C; Parker, W; Parkes, C; Passaleva, G; Patel, G D; Patel, M; Patrignani, C; Pearce, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perret, P; Pescatore, L; Petridis, K; Petrolini, A; Petruzzo, M; Picatoste Olloqui, E; Pietrzyk, B; Pikies, M; Pinci, D; Pistone, A; Piucci, A; Playfer, S; Plo Casasus, M; Poikela, T; Polci, F; Poluektov, A; Polyakov, I; Polycarpo, E; Popov, A; Popov, D; Popovici, B; Potterat, C; Price, E; Price, J D; Prisciandaro, J; Pritchard, A; Prouve, C; Pugatch, V; Puig Navarro, A; Punzi, G; Qian, W; Quagliani, R; Rachwal, B; Rademacker, J H; Rama, M; Ramos Pernas, M; Rangel, M S; Raniuk, I; Raven, G; Redi, F; Reichert, S; Dos Reis, A C; Renaudin, V; Ricciardi, S; Richards, S; Rihl, M; Rinnert, K; Rives Molina, V; Robbe, P; Rodrigues, A B; Rodrigues, E; Rodriguez Lopez, J A; Rodriguez Perez, P; Rogozhnikov, A; Roiser, S; Romanovsky, V; Romero Vidal, A; Ronayne, J W; Rotondo, M; Ruf, T; Ruiz Valls, P; Saborido Silva, J J; Sagidova, N; Saitta, B; Salustino Guimaraes, V; Sanchez Mayordomo, C; Sanmartin Sedes, B; Santacesaria, R; Santamarina Rios, C; Santimaria, M; Santovetti, E; Sarti, A; Satriano, C; Satta, A; Saunders, D M; Savrina, D; Schael, S; Schiller, M; Schindler, H; Schlupp, M; Schmelling, M; Schmelzer, T; Schmidt, B; Schneider, O; Schopper, A; Schubiger, M; Schune, M-H; Schwemmer, R; Sciascia, B; Sciubba, A; Semennikov, A; Sergi, A; Serra, N; Serrano, J; Sestini, L; Seyfert, P; Shapkin, M; Shapoval, I; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, V; Shires, A; Siddi, B G; Silva Coutinho, R; Silva de Oliveira, L; Simi, G; Sirendi, M; Skidmore, N; Skwarnicki, T; Smith, E; Smith, I T; Smith, J; Smith, M; Snoek, H; Sokoloff, M D; Soler, F J P; Soomro, F; Souza, D; Souza De Paula, B; Spaan, B; Spradlin, P; Sridharan, S; Stagni, F; Stahl, M; Stahl, S; Stefkova, S; Steinkamp, O; Stenyakin, O; Stevenson, S; Stoica, S; Stone, S; Storaci, B; Stracka, S; Straticiuc, M; Straumann, U; Sun, L; Sutcliffe, W; Swientek, K; Swientek, S; Syropoulos, V; Szczekowski, M; Szumlak, T; T'Jampens, S; Tayduganov, A; Tekampe, T; Tellarini, G; Teubert, F; Thomas, C; Thomas, E; van Tilburg, J; Tisserand, V; Tobin, M; Tolk, S; Tomassetti, L; Tonelli, D; Topp-Joergensen, S; Tournefier, E; Tourneur, S; Trabelsi, K; Traill, M; Tran, M T; Tresch, M; Trisovic, A; Tsaregorodtsev, A; Tsopelas, P; Tuning, N; Ukleja, A; Ustyuzhanin, A; Uwer, U; Vacca, C; Vagnoni, V; Valat, S; Valenti, G; Vallier, A; Vazquez Gomez, R; Vazquez Regueiro, P; Vázquez Sierra, C; Vecchi, S; van Veghel, M; Velthuis, J J; Veltri, M; Veneziano, G; Vesterinen, M; Viaud, B; Vieira, D; Vieites Diaz, M; Vilasis-Cardona, X; Volkov, V; Vollhardt, A; Voong, D; Vorobyev, A; Vorobyev, V; Voß, C; de Vries, J A; Waldi, R; Wallace, C; Wallace, R; Walsh, J; Wang, J; Ward, D R; Watson, N K; Websdale, D; Weiden, A; Whitehead, M; Wicht, J; Wilkinson, G; Wilkinson, M; Williams, M; Williams, M P; Williams, M; Williams, T; Wilson, F F; Wimberley, J; Wishahi, J; Wislicki, W; Witek, M; Wormser, G; Wotton, S A; Wraight, K; Wright, S; Wyllie, K; Xie, Y; Xu, Z; Yang, Z; Yin, H; Yu, J; Yuan, X; Yushchenko, O; Zangoli, M; Zavertyaev, M; Zhang, L; Zhang, Y; Zhelezov, A; Zheng, Y; Zhokhov, A; Zhong, L; Zhukov, V; Zucchelli, S
2016-06-17
Violations of CPT symmetry and Lorentz invariance are searched for by studying interference effects in B^{0} mixing and in B_{s}^{0} mixing. Samples of B^{0}→J/ψK_{S}^{0} and B_{s}^{0}→J/ψK^{+}K^{-} decays are recorded by the LHCb detector in proton-proton collisions at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb^{-1}. No periodic variations of the particle-antiparticle mass differences are found, consistent with Lorentz invariance and CPT symmetry. Results are expressed in terms of the standard model extension parameter Δa_{μ} with precisions of O(10^{-15}) and O(10^{-14}) GeV for the B^{0} and B_{s}^{0} systems, respectively. With no assumption on Lorentz (non)invariance, the CPT-violating parameter z in the B_{s}^{0} system is measured for the first time and found to be Re(z)=-0.022±0.033±0.005 and Im(z)=0.004±0.011±0.002, where the first uncertainties are statistical and the second systematic.
High Energy Astrophysics Tests of Lorentz Invariance and Quantum Gravity Models
NASA Technical Reports Server (NTRS)
Stecker, Floyd W.
2012-01-01
High energy astrophysics observations provide the best possibilities to detect a very small violation of Lorentz invariance such as may be related to the structure of space-time near the Planck scale of approx.10(exp -35) m. I will discuss the possible signatures of Lorentz invariance violation (LIV) that can be manifested by observing of the spectra, polarization, and timing of gamma-rays from active galactic nuclei and gamma-ray bursts. Other sensitive tests are provided by observations of the spectra of ultrahigh energy cosmic rays and neutrinos. Using the latest data from the Pierre Auger Observatory one can already derive an upper limit of 4.5 x 10(exp -23) on the fraction of LIV at a Lorentz factor of approx. 2 x 10(exp 11). This result has fundamental implications for quantum gravity models. I will also discuss the possibilities of using more sensitive space-based detection techniques to improve searches for LIV in the future. I will also discuss how the LIV formalism casts doubt on the OPERA superluminal neutrino claim.
High Energy Astrophysics Tests of Lorentz Invariance and Quantum Gravity Models
NASA Technical Reports Server (NTRS)
Stecker, F. W.
2011-01-01
High energy astrophysics observations provide the best possibilities to detect a very small violation of Lorentz invariance such as may be related to the structure of space-time near the Planck scale of approximately 10(exp -35)m. I will discuss the possible signatures of Lorentz invariance violation (LIV) that can be manifested by observing of the spectra, polarization, and timing of gamma-rays from active galactic nuclei and y-ray bursts. Other sensitive tests are provided by observations of the spectra of ultrahigh energy cosmic rays and neutrinos. Using the latest data from the Pierre Auger Observatory one can already derive an upper limit of 4.5 x 10(exp -23) on the fraction of LIV at a Lorentz factor of approximately 2 x 10(exp 11). This result has fundamental implications for quantum gravity models. I will also discuss the possibilities of using more sensitive space-based detection techniques to improve searches for LIV in the future.
Operator constraints for twist-3 functions and Lorentz invariance properties of twist-3 observables
Kanazawa, Koichi; Pitonyak, Daniel; Koike, Yuji; Metz, Andreas; Schlegel, Marc
2016-03-14
We investigate the behavior under Lorentz transformations of perturbative coefficient functions in a collinear twist-3 formalism relevant for high-energy observables including transverse polarization of hadrons. We argue that those perturbative coefficient functions can, a priori, acquire quite different yet Lorentz-invariant forms in various frames. This somewhat surprising difference can be traced back to a general dependence of the perturbative coefficient functions on light cone vectors which are introduced by the twist-3 factorization formulas and which are frame-dependent. One can remove this spurious frame dependence by invoking so-called Lorentz invariance relations (LIRs) between twist-3 parton correlation functions. Some of those relations for twist-3 distribution functions were discussed in the literature before. In this paper we derive the corresponding LIRs for twist-3 fragmentation functions. We explicitly demonstrate that these LIRs remove the light cone vector dependence by considering transverse spin observables in the single-inclusive production of hadrons in lepton-nucleon collisions, ℓN→hX. Furthermore, with the LIRs in hand, we also show that twist-3 observables in general can be written solely in terms of three-parton correlation functions.
Operator constraints for twist-3 functions and Lorentz invariance properties of twist-3 observables
Kanazawa, Koichi; Pitonyak, Daniel; Koike, Yuji; ...
2016-03-14
We investigate the behavior under Lorentz transformations of perturbative coefficient functions in a collinear twist-3 formalism relevant for high-energy observables including transverse polarization of hadrons. We argue that those perturbative coefficient functions can, a priori, acquire quite different yet Lorentz-invariant forms in various frames. This somewhat surprising difference can be traced back to a general dependence of the perturbative coefficient functions on light cone vectors which are introduced by the twist-3 factorization formulas and which are frame-dependent. One can remove this spurious frame dependence by invoking so-called Lorentz invariance relations (LIRs) between twist-3 parton correlation functions. Some of those relationsmore » for twist-3 distribution functions were discussed in the literature before. In this paper we derive the corresponding LIRs for twist-3 fragmentation functions. We explicitly demonstrate that these LIRs remove the light cone vector dependence by considering transverse spin observables in the single-inclusive production of hadrons in lepton-nucleon collisions, ℓN→hX. Furthermore, with the LIRs in hand, we also show that twist-3 observables in general can be written solely in terms of three-parton correlation functions.« less
Operator constraints for twist-3 functions and Lorentz invariance properties of twist-3 observables
NASA Astrophysics Data System (ADS)
Kanazawa, Koichi; Koike, Yuji; Metz, Andreas; Pitonyak, Daniel; Schlegel, Marc
2016-03-01
We investigate the behavior under Lorentz transformations of perturbative coefficient functions in a collinear twist-3 formalism relevant for high-energy observables including transverse polarization of hadrons. We argue that those perturbative coefficient functions can, a priori, acquire quite different yet Lorentz-invariant forms in various frames. This somewhat surprising difference can be traced back to a general dependence of the perturbative coefficient functions on light cone vectors which are introduced by the twist-3 factorization formulas and which are frame-dependent. One can remove this spurious frame dependence by invoking so-called Lorentz invariance relations (LIRs) between twist-3 parton correlation functions. Some of those relations for twist-3 distribution functions were discussed in the literature before. In this paper we derive the corresponding LIRs for twist-3 fragmentation functions. We explicitly demonstrate that these LIRs remove the light cone vector dependence by considering transverse spin observables in the single-inclusive production of hadrons in lepton-nucleon collisions, ℓN →h X . With the LIRs in hand, we also show that twist-3 observables in general can be written solely in terms of three-parton correlation functions.
Tests of local Lorentz invariance violation of gravity in the standard model extension with pulsars.
Shao, Lijing
2014-03-21
The standard model extension is an effective field theory introducing all possible Lorentz-violating (LV) operators to the standard model and general relativity (GR). In the pure-gravity sector of minimal standard model extension, nine coefficients describe dominant observable deviations from GR. We systematically implemented 27 tests from 13 pulsar systems to tightly constrain eight linear combinations of these coefficients with extensive Monte Carlo simulations. It constitutes the first detailed and systematic test of the pure-gravity sector of minimal standard model extension with the state-of-the-art pulsar observations. No deviation from GR was detected. The limits of LV coefficients are expressed in the canonical Sun-centered celestial-equatorial frame for the convenience of further studies. They are all improved by significant factors of tens to hundreds with existing ones. As a consequence, Einstein's equivalence principle is verified substantially further by pulsar experiments in terms of local Lorentz invariance in gravity.
Cold atom clock test of Lorentz invariance in the matter sector.
Wolf, Peter; Chapelet, Fréderic; Bize, Sébastien; Clairon, André
2006-02-17
We report on a new experiment that tests for a violation of Lorentz invariance (LI), by searching for a dependence of atomic transition frequencies on the orientation of the spin of the involved states (Hughes-Drever type experiment). The atomic frequencies are measured using a laser cooled 133Cs atomic fountain clock, operating on a particular combination of Zeeman substates. We analyze the results within the framework of the Lorentz violating standard model extension (SME), where our experiment is sensitive to a largely unexplored region of the SME parameter space, corresponding to first measurements of four proton parameters and improvements by 11 and 13 orders of magnitude on the determination of four others. In spite of the attained uncertainties, and of having extended the search into a new region of the SME, we still find no indication of LI violation.
Scalar Field Theory on κ-MINKOWSKI Space-Time and Translation and Lorentz Invariance
NASA Astrophysics Data System (ADS)
Meljanac, S.; Samsarov, A.
We investigate the properties of κ-Minkowski space-time by using representations of the corresponding deformed algebra in terms of undeformed Heisenberg-Weyl algebra. The deformed algebra consists of κ-Poincaré algebra extended with the generators of the deformed Weyl algebra. The part of deformed algebra, generated by rotation, boost and momentum generators, is described by the Hopf algebra structure. The approach used in our considerations is completely Lorentz covariant. We further use an advantage of this approach to consistently construct a star product, which has a property that under integration sign, it can be replaced by a standard pointwise multiplication, a property that was since known to hold for Moyal but not for κ-Minkowski space-time. This star product also has generalized trace and cyclic properties, and the construction alone is accomplished by considering a classical Dirac operator representation of deformed algebra and requiring it to be Hermitian. We find that the obtained star product is not translationally invariant, leading to a conclusion that the classical Dirac operator representation is the one where translation invariance cannot simultaneously be implemented along with hermiticity. However, due to the integral property satisfied by the star product, noncommutative free scalar field theory does not have a problem with translation symmetry breaking and can be shown to reduce to an ordinary free scalar field theory without nonlocal features and tachyonic modes and basically of the very same form. The issue of Lorentz invariance of the theory is also discussed.
Phenomenological constraints on AN in p↑p → π X from Lorentz invariance relations
NASA Astrophysics Data System (ADS)
Gamberg, Leonard; Kang, Zhong-Bo; Pitonyak, Daniel; Prokudin, Alexei
2017-07-01
We present a new analysis of AN in p↑ p → π X within the collinear twist-3 factorization formalism. We incorporate recently derived Lorentz invariance relations into our calculation and focus on input from the kinematical twist-3 functions, which are weighted integrals of transverse momentum dependent (TMD) functions. In particular, we use the latest extractions of the Sivers and Collins functions with TMD evolution to compute certain terms in AN. Consequently, we are able to constrain the remaining contributions from the lesser known dynamical twist-3 correlators.
NASA Astrophysics Data System (ADS)
Giorgini, Miriam
2006-09-01
The energy spectrum of neutrino-induced upward-going muons in MACRO was analysed in terms of special relativity principles violating effects, keeping standard mass-induced atmospheric neutrino oscillations as the dominant source of nu_mu <--> nu_tau transitions. The data disfavour these exotic possibilities even at a sub-dominant level, and stringent 90% C.L. limits are placed on the Lorentz invariance violation parameters. These limits can also be re-interpreted as upper bounds on the parameters describing violation of the Equivalence Principle.
Testing the Equivalence Principle and Lorentz Invariance with PeV Neutrinos from Blazar Flares.
Wang, Zi-Yi; Liu, Ruo-Yu; Wang, Xiang-Yu
2016-04-15
It was recently proposed that a giant flare of the blazar PKS B1424-418 at redshift z=1.522 is in association with a PeV-energy neutrino event detected by IceCube. Based on this association we here suggest that the flight time difference between the PeV neutrino and gamma-ray photons from blazar flares can be used to constrain the violations of equivalence principle and the Lorentz invariance for neutrinos. From the calculated Shapiro delay due to clusters or superclusters in the nearby universe, we find that violation of the equivalence principle for neutrinos and photons is constrained to an accuracy of at least 10^{-5}, which is 2 orders of magnitude tighter than the constraint placed by MeV neutrinos from supernova 1987A. Lorentz invariance violation (LIV) arises in various quantum-gravity theories, which predicts an energy-dependent velocity of propagation in vacuum for particles. We find that the association of the PeV neutrino with the gamma-ray outburst set limits on the energy scale of possible LIV to >0.01E_{pl} for linear LIV models and >6×10^{-8}E_{pl} for quadratic order LIV models, where E_{pl} is the Planck energy scale. These are the most stringent constraints on neutrino LIV for subluminal neutrinos.
Lorentz Invariance Violation and the Observed Spectrum of Ultrahigh Energy Cosmic Rays
NASA Technical Reports Server (NTRS)
Scully, S. T.; Stecker, F. W.
2009-01-01
There has been much interest in possible violations of Lorentz invariance, particularly motivated by quantum gravity theories. It has been suggested that a small amount of Lorentz invariance violation (LIV) could turn of photomeson interactions of ultrahigh energy cosmic rays (UHECRs) with photons of the cosmic background radiation and thereby eliminate the resulting sharp steepening in the spectrum of the highest energy CRs predicted by Greisen Zatsepin and Kuzmin (GZK). Recent measurements of the UHECR spectrum reported by the HiRes and Auger collaborations, however, indicate the presence of the GZK effect. We present the results of a detailed calculation of the modification of the UHECR spectrum caused by LIV using the formalism of Coleman and Glashow. We then compare these results with the experimental UHECR data from Auger and HiRes. Based on these data, we find a best fit amount of LIV of 4.5+1:5 ..4:5 x 10(exp -23),consistent with an upper limit of 6 x 10(exp -23). This possible amount of LIV can lead to a recovery of the cosmic ray spectrum at higher energies than presently observed. Such an LIV recovery effect can be tested observationally using future detectors.
The Spectrum of Ultrahigh Energy Cosmic Rays and Constraints on Lorentz Invariance Violation
NASA Technical Reports Server (NTRS)
Stecker, F. W.
2008-01-01
There has been much interest in possible violations of Lorentz invariance, particularly motivated by quantum gravity theories. It has been suggested that a small amount of Lorentz invariance violation (LIV) could turn off photomeson interactions of ultrahigh energy cosmic rays (UHECRs) with photons of the cosmic background radiation and thereby eliminate the resulting sharp steepening in the spectrum of the highest energy CRs predicted by Greisen Zatsepin and Kuzmin (GZK). Recent measurements of the UHECR spectrum reported by the HiRes and Auger collaborations, however, indicate the presence of the GZK effect. We present the results of a detailed calculation of the modification of the UHECR spectrum caused by LIV using the formalism of Coleman and Glashow. We then use a chi-squared analysis to compare our results with the experimental UHECR data and thereby place limits on the amount of LIV. We also discuss how a small amount of LIV that is consistent with the experimental data can still lead to a recovery of the cosmic ray flux at higher energies than presently observed.
NASA Astrophysics Data System (ADS)
Dai, Wei-Ming; Guo, Zong-Kuan; Cai, Rong-Gen; Zhang, Yuan-Zhong
2017-06-01
We investigate constraints on Lorentz invariance violation in the neutrino sector from a joint analysis of big bang nucleosynthesis and the cosmic microwave background. The effect of Lorentz invariance violation during the epoch of big bang nucleosynthesis changes the predicted helium-4 abundance, which influences the power spectrum of the cosmic microwave background at the recombination epoch. In combination with the latest measurement of the primordial helium-4 abundance, the Planck 2015 data of the cosmic microwave background anisotropies give a strong constraint on the deformation parameter since adding the primordial helium measurement breaks the degeneracy between the deformation parameter and the physical dark matter density.
A Z{sub 3} generalization of Pauli's principle, quark algebra and the Lorentz invariance
Kerner, Richard
2012-09-24
The fundamental difference between bosons and fermions is that they obey two alternative representations of the Z{sub 2} group, resulting in symmetric or anti-symmetric binary commutation relations. Our aim is to explore possibilities offered by ternary Z{sub 3} generalization commutation relations. This leads to cubic and ternary algebras which are a direct generalization of usual commutation relations, with Z{sub 3}-grading replacing the usual Z{sub 2}-grading. Properties and structure of such algebras are discussed, with special interest in a low-dimensional one, with two generators. Invariant cubic forms on such algebras are introduced, and it is shown how the SL(2,C) group arises naturally as the symmetry group preserving these forms. In the case of lowest dimension, with only two generators, it is shown how the cubic combinations of elements of the same Z{sub 3} grade behave like Lorentz spinors, while binary products of elements of this algebra with an element of the conjugate algebra behave like Lorentz vectors. The wave equation generalizing the Dirac operator to the Z{sub 3}-graded case is introduced, whose diagonalization leads to a third-order equation. The solutions of this equation cannot propagate because their exponents always contain non-oscillating real damping factor. We show how certain cubic products can propagate nevertheless. The model suggests the origin of the color SU(3) symmetry obeyed by quark states.
No static black hole hairs in gravitational theories with broken Lorentz invariance
NASA Astrophysics Data System (ADS)
Lin, Kai; Mukohyama, Shinji; Wang, Anzhong; Zhu, Tao
2017-06-01
In this paper, we revisit the issue of static hairs of black holes in gravitational theories with broken Lorentz invariance in the case that the speed cϕ of the khronon field becomes infinitely large, cϕ=∞ , for which the sound horizon of the khronon field coincides with the universal horizon, and the boundary conditions at the sound horizon reduce to those given normally at the universal horizons. As a result, fewer boundary conditions are present in this extreme case in comparison with the case cϕ=finite . Consequently, it is expected that static hairs might exist. However, we show analytically that, even in this case, static hairs still cannot exist, based on a decoupling limit analysis. We also consider the cases in which cϕ is finite but with cϕ≫1 , and we obtain the same conclusion.
Stanwix, Paul L.; Tobar, Michael E.; Susli, Mohamad; Locke, Clayton R.; Ivanov, Eugene N.; Winterflood, John; Kann, Frank van; Wolf, Peter
2005-07-22
We present the first results from a rotating Michelson-Morley experiment that uses two orthogonally orientated cryogenic sapphire resonator oscillators operating in whispering gallery modes near 10 GHz. The experiment is used to test for violations of Lorentz invariance in the framework of the photon sector of the standard model extension (SME), as well as the isotropy term of the Robertson-Mansouri-Sexl (RMS) framework. In the SME we set a new bound on the previously unmeasured {kappa}-tilde{sub e-}{sup ZZ} component of 2.1(5.7)x10{sup -14}, and set more stringent bounds by up to a factor of 7 on seven other components. In the RMS a more stringent bound of -0.9(2.0)x10{sup -10} on the isotropy parameter, P{sub MM}={delta}-{beta}+(1/2) is set, which is more than a factor of 7 improvement.
Testing Lorentz Invariance with Neutrinos from Ultrahigh Energy Cosmic Ray Interactions
NASA Technical Reports Server (NTRS)
Scully, Sean T.; Stecker, Floyd W.
2010-01-01
We have previously shown that a very small amount of Lorentz invariance violation (UV), which suppresses photomeson interactions of ultrahigh energy cosmic rays (UHECRs) with cosmic background radiation (CBR) photons, can produce a spectrum of cosmic rays that is consistent with that currently observed by the Pierre Auger Observatory (PAO) and HiRes experiments. Here, we calculate the corresponding flux of high energy neutrinos generated by the propagation of UHECR protons through the CBR in the presence of UV. We find that UV produces a reduction in the flux of the highest energy neutrinos and a reduction in the energy of the peak of the neutrino energy flux spectrum, both depending on the strength of the UV. Thus, observations of the UHE neutrino spectrum provide a clear test for the existence and amount of UV at the highest energies. We further discuss the ability of current and future proposed detectors make such observations.
Searching the laws of thermodynamics in the Lorentz-invariant thermal energy propagation equation
NASA Astrophysics Data System (ADS)
Szőllősi, Tibor; Márkus, Ferenc
2015-09-01
In earlier works it has been shown that the Lorentz-invariant description of thermal energy transfer can be deduced from a Lagrangian description, by which the definition of a dynamic temperature is involved at the same time. It is also proved that this formulation includes the classical Fourier heat propagation as a natural limit. However, the relation of the elaborated theory to the basic laws of thermodynamics remained open. This connection is studied in details in the present paper. It is posted that though strictly speaking the model is meaningless in equilibrium and corresponds only to the non-equilibrium parts of the temperature, it respects the laws of thermodynamics and provides a way to transfer some form of them into the validity-area of the model.
Testing Lorentz invariance with neutrinos from ultrahigh energy cosmic ray interactions
NASA Astrophysics Data System (ADS)
Scully, Sean T.; Stecker, Floyd W.
2011-02-01
We have previously shown that a very small amount of Lorentz invariance violation (LIV), which suppresses photomeson interactions of ultrahigh energy cosmic rays (UHECRs) with cosmic background radiation (CBR) photons, can produce a spectrum of cosmic rays that is consistent with that currently observed by the Pierre Auger Observatory (PAO) and HiRes experiments. Here, we calculate the corresponding flux of high energy neutrinos generated by the propagation of UHECR protons through the CBR in the presence of LIV. We find that LIV produces a reduction in the flux of the highest energy neutrinos and a reduction in the energy of the peak of the neutrino energy flux spectrum, both depending on the strength of the LIV. Thus, observations of the UHE neutrino spectrum provide a clear test for the existence and amount of LIV at the highest energies. We further discuss the ability of current and future proposed detectors make such observations.
Search for Violation of CPT and Lorentz Invariance in Bs(0) Meson Oscillations.
Abazov, V M; Abbott, B; Acharya, B S; Adams, M; Adams, T; Agnew, J P; Alexeev, G D; Alkhazov, G; Alton, A; Askew, A; Atkins, S; Augsten, K; Avila, C; Badaud, F; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, S; Barberis, E; Baringer, P; Bartlett, J F; Bassler, U; Bazterra, V; Bean, A; Begalli, M; Bellantoni, L; Beri, S B; Bernardi, G; Bernhard, R; Bertram, I; Besançon, M; Beuselinck, R; Bhat, P C; Bhatia, S; Bhatnagar, V; Blazey, G; Blessing, S; Bloom, K; Boehnlein, A; Boline, D; Boos, E E; Borissov, G; Borysova, M; Brandt, A; Brandt, O; Brock, R; Bross, A; Brown, D; Bu, X B; Buehler, M; Buescher, V; Bunichev, V; Burdin, S; Buszello, C P; Camacho-Pérez, E; Casey, B C K; Castilla-Valdez, H; Caughron, S; Chakrabarti, S; Chan, K M; Chandra, A; Chapon, E; Chen, G; Cho, S W; Choi, S; Choudhary, B; Cihangir, S; Claes, D; Clutter, J; Cooke, M; Cooper, W E; Corcoran, M; Couderc, F; Cousinou, M-C; Cuth, J; Cutts, D; Das, A; Davies, G; de Jong, S J; De La Cruz-Burelo, E; Déliot, F; Demina, R; Denisov, D; Denisov, S P; Desai, S; Deterre, C; DeVaughan, K; Diehl, H T; Diesburg, M; Ding, P F; Dominguez, A; Dubey, A; Dudko, L V; Duperrin, A; Dutt, S; Eads, M; Edmunds, D; Ellison, J; Elvira, V D; Enari, Y; Evans, H; Evdokimov, A; Evdokimov, V N; Fauré, A; Feng, L; Ferbel, T; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Fortner, M; Fox, H; Fuess, S; Garbincius, P H; Garcia-Bellido, A; García-González, J A; Gavrilov, V; Geng, W; Gerber, C E; Gershtein, Y; Ginther, G; Gogota, O; Golovanov, G; Grannis, P D; Greder, S; Greenlee, H; Grenier, G; Gris, Ph; Grivaz, J-F; Grohsjean, A; Grünendahl, S; Grünewald, M W; Guillemin, T; Gutierrez, G; Gutierrez, P; Haley, J; Han, L; Harder, K; Harel, A; Hauptman, J M; Hays, J; Head, T; Hebbeker, T; Hedin, D; Hegab, H; Heinson, A P; Heintz, U; Hensel, C; Heredia-De La Cruz, I; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hoang, T; Hobbs, J D; Hoeneisen, B; Hogan, J; Hohlfeld, M; Holzbauer, J L; Howley, I; Hubacek, Z; Hynek, V; Iashvili, I; Ilchenko, Y; Illingworth, R; Ito, A S; Jabeen, S; Jaffré, M; Jayasinghe, A; Jeong, M S; Jesik, R; Jiang, P; Johns, K; Johnson, E; Johnson, M; Jonckheere, A; Jonsson, P; Joshi, J; Jung, A W; Juste, A; Kajfasz, E; Karmanov, D; Katsanos, I; Kaur, M; Kehoe, R; Kermiche, S; Khalatyan, N; Khanov, A; Kharchilava, A; Kharzheev, Y N; Kiselevich, I; Kohli, J M; Kozelov, A V; Kraus, J; Kumar, A; Kupco, A; Kurča, T; Kuzmin, V A; Lammers, S; Lebrun, P; Lee, H S; Lee, S W; Lee, W M; Lei, X; Lellouch, J; Li, D; Li, H; Li, L; Li, Q Z; Lim, J K; Lincoln, D; Linnemann, J; Lipaev, V V; Lipton, R; Liu, H; Liu, Y; Lobodenko, A; Lokajicek, M; Lopes de Sa, R; Luna-Garcia, R; Lyon, A L; Maciel, A K A; Madar, R; Magaña-Villalba, R; Malik, S; Malyshev, V L; Mansour, J; Martínez-Ortega, J; McCarthy, R; McGivern, C L; Meijer, M M; Melnitchouk, A; Menezes, D; Mercadante, P G; Merkin, M; Meyer, A; Meyer, J; Miconi, F; Mondal, N K; Mulhearn, M; Nagy, E; Narain, M; Nayyar, R; Neal, H A; Negret, J P; Neustroev, P; Nguyen, H T; Nunnemann, T; Orduna, J; Osman, N; Osta, J; Pal, A; Parashar, N; Parihar, V; Park, S K; Partridge, R; Parua, N; Patwa, A; Penning, B; Perfilov, M; Peters, Y; Petridis, K; Petrillo, G; Pétroff, P; Pleier, M-A; Podstavkov, V M; Popov, A V; Prewitt, M; Price, D; Prokopenko, N; Qian, J; Quadt, A; Quinn, B; Ratoff, P N; Razumov, I; Ripp-Baudot, I; Rizatdinova, F; Rominsky, M; Ross, A; Royon, C; Rubinov, P; Ruchti, R; Sajot, G; Sánchez-Hernández, A; Sanders, M P; Santos, A S; Savage, G; Savitskyi, M; Sawyer, L; Scanlon, T; Schamberger, R D; Scheglov, Y; Schellman, H; Schott, M; Schwanenberger, C; Schwienhorst, R; Sekaric, J; Severini, H; Shabalina, E; Shary, V; Shaw, S; Shchukin, A A; Simak, V; Skubic, P; Slattery, P; Smirnov, D; Snow, G R; Snow, J; Snyder, S; Söldner-Rembold, S; Sonnenschein, L; Soustruznik, K; Stark, J; Stoyanova, D A; Strauss, M; Suter, L; Svoisky, P; Titov, M; Tokmenin, V V; Tsai, Y-T; Tsybychev, D; Tuchming, B; Tully, C; Uvarov, L; Uvarov, S; Uzunyan, S; Van Kooten, R; van Leeuwen, W M; Varelas, N; Varnes, E W; Vasilyev, I A; Verkheev, A Y; Vertogradov, L S; Verzocchi, M; Vesterinen, M; Vilanova, D; Vokac, P; Wahl, H D; Wang, M H L S; Warchol, J; Watts, G; Wayne, M; Weichert, J; Welty-Rieger, L; Williams, M R J; Wilson, G W; Wobisch, M; Wood, D R; Wyatt, T R; Xie, Y; Yamada, R; Yang, S; Yasuda, T; Yatsunenko, Y A; Ye, W; Ye, Z; Yin, H; Yip, K; Youn, S W; Yu, J M; Zennamo, J; Zhao, T G; Zhou, B; Zhu, J; Zielinski, M; Zieminska, D; Zivkovic, L
2015-10-16
We present the first search for CPT-violating effects in the mixing of Bs(0) mesons using the full Run II data set with an integrated luminosity of 10.4 fb(-1) of proton-antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. We measure the CPT-violating asymmetry in the decay Bs(0)→μ(±)Ds(±) as a function of celestial direction and sidereal phase. We find no evidence for CPT-violating effects and place limits on the direction and magnitude of flavor-dependent CPT- and Lorentz-invariance violating coupling coefficients. We find 95% confidence intervals of Δa⊥<1.2×10(-12) GeV and (-0.8<ΔaT-0.396ΔaZ<3.9)×10(-13) GeV.
Flambaum, V V
2016-08-12
Local Lorentz invariance violating (LLIV) and Einstein equivalence principle violating (EEPV) effects in atomic experiments are discussed. The EEPV effects are strongly enhanced in the narrow 7.8 eV transition in the _{90}^{229}Th nucleus. The nuclear LLIV tensors describing the anisotropy in the maximal attainable speed for massive particles (analog of the Michelson-Morley experiment for light) are expressed in terms of the experimental values of the nuclear quadrupole moments. Calculations for nuclei of experimental interest _{55}^{133}Cs, _{37}^{85}Rb, _{37}^{87}Rb, _{80}^{201}Hg, _{54}^{131}Xe, and _{10}^{21}Ne are performed. The results for _{10}^{21}Ne are used to improve the limits on the proton LLIV interaction constants by 4 orders of magnitude.
Testing Lorentz Invariance with Neutrinos from Ultrahigh Energy Cosmic Ray Interactions
NASA Technical Reports Server (NTRS)
Scully, Sean T.; Stecker, Floyd W.
2010-01-01
We have previously shown that a very small amount of Lorentz invariance violation (UV), which suppresses photomeson interactions of ultrahigh energy cosmic rays (UHECRs) with cosmic background radiation (CBR) photons, can produce a spectrum of cosmic rays that is consistent with that currently observed by the Pierre Auger Observatory (PAO) and HiRes experiments. Here, we calculate the corresponding flux of high energy neutrinos generated by the propagation of UHECR protons through the CBR in the presence of UV. We find that UV produces a reduction in the flux of the highest energy neutrinos and a reduction in the energy of the peak of the neutrino energy flux spectrum, both depending on the strength of the UV. Thus, observations of the UHE neutrino spectrum provide a clear test for the existence and amount of UV at the highest energies. We further discuss the ability of current and future proposed detectors make such observations.
Search for Violation of C P T and Lorentz Invariance in Bs0 Meson Oscillations
NASA Astrophysics Data System (ADS)
Abazov, V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Agnew, J. P.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Askew, A.; Atkins, S.; Augsten, K.; Avila, C.; Badaud, F.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Barberis, E.; Baringer, P.; Bartlett, J. F.; Bassler, U.; Bazterra, V.; Bean, A.; Begalli, M.; Bellantoni, L.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besançon, M.; Beuselinck, R.; Bhat, P. C.; Bhatia, S.; Bhatnagar, V.; Blazey, G.; Blessing, S.; Bloom, K.; Boehnlein, A.; Boline, D.; Boos, E. E.; Borissov, G.; Borysova, M.; Brandt, A.; Brandt, O.; Brock, R.; Bross, A.; Brown, D.; Bu, X. B.; Buehler, M.; Buescher, V.; Bunichev, V.; Burdin, S.; Buszello, C. P.; Camacho-Pérez, E.; Casey, B. C. K.; Castilla-Valdez, H.; Caughron, S.; Chakrabarti, S.; Chan, K. M.; Chandra, A.; Chapon, E.; Chen, G.; Cho, S. W.; Choi, S.; Choudhary, B.; Cihangir, S.; Claes, D.; Clutter, J.; Cooke, M.; Cooper, W. E.; Corcoran, M.; Couderc, F.; Cousinou, M.-C.; Cuth, J.; Cutts, D.; Das, A.; Davies, G.; de Jong, S. J.; De La Cruz-Burelo, E.; Déliot, F.; Demina, R.; Denisov, D.; Denisov, S. P.; Desai, S.; Deterre, C.; DeVaughan, K.; Diehl, H. T.; Diesburg, M.; Ding, P. F.; Dominguez, A.; Dubey, A.; Dudko, L. V.; Duperrin, A.; Dutt, S.; Eads, M.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Enari, Y.; Evans, H.; Evdokimov, A.; Evdokimov, V. N.; Fauré, A.; Feng, L.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Fortner, M.; Fox, H.; Fuess, S.; Garbincius, P. H.; Garcia-Bellido, A.; García-González, J. A.; Gavrilov, V.; Geng, W.; Gerber, C. E.; Gershtein, Y.; Ginther, G.; Gogota, O.; Golovanov, G.; Grannis, P. D.; Greder, S.; Greenlee, H.; Grenier, G.; Gris, Ph.; Grivaz, J.-F.; Grohsjean, A.; Grünendahl, S.; Grünewald, M. W.; Guillemin, T.; Gutierrez, G.; Gutierrez, P.; Haley, J.; Han, L.; Harder, K.; Harel, A.; Hauptman, J. M.; Hays, J.; Head, T.; Hebbeker, T.; Hedin, D.; Hegab, H.; Heinson, A. P.; Heintz, U.; Hensel, C.; Heredia-De La Cruz, I.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hoang, T.; Hobbs, J. D.; Hoeneisen, B.; Hogan, J.; Hohlfeld, M.; Holzbauer, J. L.; Howley, I.; Hubacek, Z.; Hynek, V.; Iashvili, I.; Ilchenko, Y.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffré, M.; Jayasinghe, A.; Jeong, M. S.; Jesik, R.; Jiang, P.; Johns, K.; Johnson, E.; Johnson, M.; Jonckheere, A.; Jonsson, P.; Joshi, J.; Jung, A. W.; Juste, A.; Kajfasz, E.; Karmanov, D.; Katsanos, I.; Kaur, M.; Kehoe, R.; Kermiche, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. N.; Kiselevich, I.; Kohli, J. M.; Kozelov, A. V.; Kraus, J.; Kumar, A.; Kupco, A.; Kurča, T.; Kuzmin, V. A.; Lammers, S.; Lebrun, P.; Lee, H. S.; Lee, S. W.; Lee, W. M.; Lei, X.; Lellouch, J.; Li, D.; Li, H.; Li, L.; Li, Q. Z.; Lim, J. K.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, H.; Liu, Y.; Lobodenko, A.; Lokajicek, M.; Lopes de Sa, R.; Luna-Garcia, R.; Lyon, A. L.; Maciel, A. K. A.; Madar, R.; Magaña-Villalba, R.; Malik, S.; Malyshev, V. L.; Mansour, J.; Martínez-Ortega, J.; McCarthy, R.; McGivern, C. L.; Meijer, M. M.; Melnitchouk, A.; Menezes, D.; Mercadante, P. G.; Merkin, M.; Meyer, A.; Meyer, J.; Miconi, F.; Mondal, N. K.; Mulhearn, M.; Nagy, E.; Narain, M.; Nayyar, R.; Neal, H. A.; Negret, J. P.; Neustroev, P.; Nguyen, H. T.; Nunnemann, T.; Orduna, J.; Osman, N.; Osta, J.; Pal, A.; Parashar, N.; Parihar, V.; Park, S. K.; Partridge, R.; Parua, N.; Patwa, A.; Penning, B.; Perfilov, M.; Peters, Y.; Petridis, K.; Petrillo, G.; Pétroff, P.; Pleier, M.-A.; Podstavkov, V. M.; Popov, A. V.; Prewitt, M.; Price, D.; Prokopenko, N.; Qian, J.; Quadt, A.; Quinn, B.; Ratoff, P. N.; Razumov, I.; Ripp-Baudot, I.; Rizatdinova, F.; Rominsky, M.; Ross, A.; Royon, C.; Rubinov, P.; Ruchti, R.; Sajot, G.; Sánchez-Hernández, A.; Sanders, M. P.; Santos, A. S.; Savage, G.; Savitskyi, M.; Sawyer, L.; Scanlon, T.; Schamberger, R. D.; Scheglov, Y.; Schellman, H.; Schott, M.; Schwanenberger, C.; Schwienhorst, R.; Sekaric, J.; Severini, H.; Shabalina, E.; Shary, V.; Shaw, S.; Shchukin, A. A.; Simak, V.; Skubic, P.; Slattery, P.; Smirnov, D.; Snow, G. R.; Snow, J.; Snyder, S.; Söldner-Rembold, S.; Sonnenschein, L.; Soustruznik, K.; Stark, J.; Stoyanova, D. A.; Strauss, M.; Suter, L.; Svoisky, P.; Titov, M.; Tokmenin, V. V.; Tsai, Y.-T.; Tsybychev, D.; Tuchming, B.; Tully, C.; Uvarov, L.; Uvarov, S.; Uzunyan, S.; Van Kooten, R.; van Leeuwen, W. M.; Varelas, N.; Varnes, E. W.; Vasilyev, I. A.; Verkheev, A. Y.; Vertogradov, L. S.; Verzocchi, M.; Vesterinen, M.; Vilanova, D.; Vokac, P.; Wahl, H. D.; Wang, M. H. L. S.; Warchol, J.; Watts, G.; Wayne, M.; Weichert, J.; Welty-Rieger, L.; Williams, M. R. J.; Wilson, G. W.; Wobisch, M.; Wood, D. R.; Wyatt, T. R.; Xie, Y.; Yamada, R.; Yang, S.; Yasuda, T.; Yatsunenko, Y. A.; Ye, W.; Ye, Z.; Yin, H.; Yip, K.; Youn, S. W.; Yu, J. M.; Zennamo, J.; Zhao, T. G.; Zhou, B.; Zhu, J.; Zielinski, M.; Zieminska, D.; Zivkovic, L.; D0 Collaboration
2015-10-01
We present the first search for C P T -violating effects in the mixing of Bs0 mesons using the full Run II data set with an integrated luminosity of 10.4 fb-1 of proton-antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. We measure the C P T -violating asymmetry in the decay Bs0→μ±Ds± as a function of celestial direction and sidereal phase. We find no evidence for C P T -violating effects and place limits on the direction and magnitude of flavor-dependent C P T - and Lorentz-invariance violating coupling coefficients. We find 95% confidence intervals of Δ a⊥<1.2 ×10-12 GeV and (-0.8 <Δ aT-0.396 Δ aZ<3.9 )×1 0-13 GeV .
NASA Astrophysics Data System (ADS)
Battistoni, G.; Becherini, Y.; Cecchini, S.; Cozzi, M.; Dekhissi, H.; Esposito, L. S.; Giacomelli, G.; Giorgini, M.; Mandrioli, G.; Manzoor, S.; Margiotta, A.; Patrizii, L.; Popa, V.; Sioli, M.; Sirri, G.; Spurio, M.; Togo, V.
2005-05-01
The energy spectrum of neutrino-induced upward-going muons in MACRO has been analysed in terms of relativity principles violating effects, keeping standard mass-induced atmospheric neutrino oscillations as the dominant source of νμ →ντ transitions. The data disfavor these exotic possibilities even at a subdominant level, and stringent 90% C.L. limits are placed on the Lorentz invariance violation parameter | Δv | < 6 ×10-24 at sin 2θv = 0 and | Δv | < 2.5- 5 ×10-26 at sin 2θv = ± 1. These limits can also be re-interpreted as upper bounds on the parameters describing violation of the equivalence principle.
Search for Violation of $CPT$ and Lorentz Invariance in $${B_s^0}$$ Meson Oscillations
Abazov, Victor Mukhamedovich
2015-06-12
We present the first search for CPT-violating effects in the mixing of B0s mesons using the full Run II data set with an integrated luminosity of 10.4 fb-1 of proton-antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. We measure the CPT-violating asymmetry in the decay B0s → µ±D±s as a function of celestial direction and sidereal phase. We find no evidence for CPT-violating effects and place limits on the direction and magnitude of flavor-dependent CPTand Lorentz-invariance violating coupling coefficients. We find 95% confidence intervals of Δa⊥ < 1.2 × 10-12 GeV and (-0.8 < ΔaT -more » 0.396ΔaZ < 3.9) × 10-13 GeV.« less
NASA Astrophysics Data System (ADS)
Cortés, J. L.; López-Sarrión, Justo
2017-05-01
In this paper, we study the consistency of having Lorentz invariance as a low energy approximation within the quantum field theory framework. A model with a scalar and a fermion field is used to show how a Lorentz invariance violating high momentum scale, a physical cutoff rendering the quantum field theory finite, can be made compatible with a suppression of Lorentz invariance violations at low momenta. The fine tuning required to get this suppression and to have a light scalar particle in the spectrum are determined at one loop.
Vasileiou, V.; Jacholkowska, A.; Piron, F.; ...
2013-06-04
For this research, we analyze the MeV/GeV emission from four bright gamma-ray bursts (GRBs) observed by the Fermi Large Area Telescope to produce robust, stringent constraints on a dependence of the speed of light in vacuo on the photon energy (vacuum dispersion), a form of Lorentz invariance violation (LIV) allowed by some quantum gravity (QG) theories. First, we use three different and complementary techniques to constrain the total degree of dispersion observed in the data. Additionally, using a maximally conservative set of assumptions on possible source-intrinsic, spectral-evolution effects, we constrain any vacuum dispersion solely attributed to LIV. We then derivemore » limits on the QG energy scale (the energy scale where LIV-inducing QG effects become strong, EQG) and the coefficients of the Standard Model Extension. For the subluminal case (where high-energy photons propagate more slowly than lower-energy photons) and without taking into account any source-intrinsic dispersion, our most stringent limits (at 95% C.L.) are obtained from GRB 090510 and are EQG,1 > 7.6 times the Planck energy (EPl) and EQG,2 > 1.3 × 1011 GeV for linear and quadratic leading-order LIV-induced vacuum dispersion, respectively. In conclusion, these limits improve the latest constraints by Fermi and H.E.S.S. by a factor of ~2 . Our results disfavor any class of models requiring EQG,1 ≲ EPl .« less
Lorentz invariance violation and simultaneous emission of electromagnetic and gravitational waves
NASA Astrophysics Data System (ADS)
Passos, E.; Anacleto, M. A.; Brito, F. A.; Holanda, O.; Souza, G. B.; Zarro, C. A. D.
2017-09-01
In this work, we compute some phenomenological bounds for the electromagnetic and massive gravitational high-derivative extensions supposing that it is possible to have an astrophysical process that generates simultaneously gravitational and electromagnetic waves. We present Lorentz invariance violating (LIV) higher-order derivative models, following the Myers-Pospelov approach, to electrodynamics and massive gravitational waves. We compute the corrected equation of motion of these models, their dispersion relations and the velocities. The LIV parameters for the gravitational and electromagnetic sectors, ξg and ξγ, respectively, were also obtained for three different approaches: luminal photons, time delay of flight and the difference of graviton and photon velocities. These LIV parameters depend on the mass scales where the LIV-terms become relevant, M for the electromagnetic sector and M1 for the gravitational one. We obtain, using the values for M and M1 found in the literature, that ξg ∼10-2, which is expected to be phenomenologically relevant and ξγ ∼103, which cannot be suitable for an effective LIV theory. However, we show that ξγ can be interesting in a phenomenological point of view if M ≫M1. Finally the relation between the variation of the velocities of the photon and the graviton in relation to the speed of light was calculated and resulted in Δvg / Δvγ ≲ 1.82 ×10-3.
A New Test of Lorentz Invariance Violation: The Spectral Lag Transition of GRB 160625B
NASA Astrophysics Data System (ADS)
Wei, Jun-Jie; Zhang, Bin-Bin; Shao, Lang; Wu, Xue-Feng; Mészáros, Peter
2017-01-01
Possible violations of Lorentz invariance (LIV) have been investigated for a long time using the observed spectral lags of gamma-ray bursts (GRBs). However, these generally have relied on using a single photon in the highest energy range. Furthermore, the search for LIV lags has been hindered by our ignorance concerning the intrinsic time lag in different energy bands. GRB 160625B, the only burst so far with a well-defined transition from positive lags to negative lags provides a unique opportunity to put new constraints on LIV. Using multi-photon energy bands we consider the contributions to the observed spectral lag from both the intrinsic time lag and the lag by LIV effects, and assuming the intrinsic time lag to have a positive dependence on the photon energy, we obtain robust limits on LIV by directly fitting the spectral lag data of GRB 160625B. Here we show that these robust limits on the quantum gravity energy scales are {E}{QG,1}≥slant 0.5× {10}16 GeV for the linear, and {E}{QG,2}≥slant 1.4× {10}7 GeV for the quadratic LIV effects, respectively. In addition, we give, for the first time, a reasonable formulation of the intrinsic energy-dependent time lag.
Search for Violation of $CPT$ and Lorentz Invariance in ${B_s^0}$ Meson Oscillations
Abazov, Victor Mukhamedovich
2015-06-12
We present the first search for CPT-violating effects in the mixing of B^{0}_{s} mesons using the full Run II data set with an integrated luminosity of 10.4 fb^{-1} of proton-antiproton collisions collected using the D0 detector at the Fermilab Tevatron Collider. We measure the CPT-violating asymmetry in the decay B^{0}_{s} → µ^{±}D^{±}_{s} as a function of celestial direction and sidereal phase. We find no evidence for CPT-violating effects and place limits on the direction and magnitude of flavor-dependent CPTand Lorentz-invariance violating coupling coefficients. We find 95% confidence intervals of Δa⊥ < 1.2 × 10^{-12} GeV and (-0.8 < ΔaT - 0.396Δa_{Z} < 3.9) × 10^{-13} GeV.
Collective Lorentz invariant dynamics on a single ‘polynomial’ worldline
NASA Astrophysics Data System (ADS)
Kassandrov, Vladimir V.; Khasanov, Ildus Sh; Markova, Nina V.
2015-10-01
Consider a worldline of a pointlike particle parameterized by polynomial functions, together with the light cone (‘retardation’) equation of an inertially moving observer. Then a set of apparent copies, R- or C-particles, defined by the (real or complex conjugate) roots of the retardation equation will be detected by the observer. We prove that for any ‘polynomial’ worldline the induced collective dynamics of R-C particles obeys a whole set of canonical conservation laws (for total momentum, angular momentum and the analogue of mechanical energy). Explicit formulas for the values of total angular momentum and the analogue of total rest energy (rest mass) are obtained; the latter is ‘self-quantized’, i.e. for any worldline takes only integer values. The dynamics is Lorentz invariant though different from the canonical relativistic mechanics. Asymptotically, at large values of the observer’s proper time, the R-C particles couple and then assemble into compact incoming/outgoing clusters. As a whole, the evolution resembles the process of (either elastic or inelastic) scattering of a beam of composite particles. Throughout the paper the consideration is purely algebraic, with no resort to differential equations of motion, field equations, etc.
Search for Violations of Lorentz Invariance and C P T Symmetry in B(s) 0 Mixing
NASA Astrophysics Data System (ADS)
Aaij, R.; Abellán Beteta, C.; Adeva, B.; Adinolfi, M.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Andreassi, G.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Aquines Gutierrez, O.; Archilli, F.; d'Argent, P.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baker, S.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Batozskaya, V.; Battista, V.; Bay, A.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Bel, L. J.; Bellee, V.; Belloli, N.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernet, R.; Bertolin, A.; Betti, F.; Bettler, M.-O.; van Beuzekom, M.; Bifani, S.; Billoir, P.; Bird, T.; Birnkraut, A.; Bizzeti, A.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Bondar, A.; Bondar, N.; Bonivento, W.; Borgheresi, A.; Borghi, S.; Borisyak, M.; Borsato, M.; Boubdir, M.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Braun, S.; Britsch, M.; Britton, T.; Brodzicka, J.; Buchanan, E.; Burr, C.; Bursche, A.; Buytaert, J.; Cadeddu, S.; Calabrese, R.; Calvi, M.; Calvo Gomez, M.; Campana, P.; Campora Perez, D.; Capriotti, L.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carniti, P.; Carson, L.; Carvalho Akiba, K.; Casse, G.; Cassina, L.; Castillo Garcia, L.; Cattaneo, M.; Cauet, Ch.; Cavallero, G.; Cenci, R.; Charles, M.; Charpentier, Ph.; Chatzikonstantinidis, G.; Chefdeville, M.; Chen, S.; Cheung, S.-F.; Chrzaszcz, M.; Cid Vidal, X.; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coco, V.; Cogan, J.; Cogneras, E.; Cogoni, V.; Cojocariu, L.; Collazuol, G.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombes, M.; Coquereau, S.; Corti, G.; Corvo, M.; Couturier, B.; Cowan, G. A.; Craik, D. C.; Crocombe, A.; Cruz Torres, M.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; Dall'Occo, E.; Dalseno, J.; David, P. N. Y.; Davis, A.; De Aguiar Francisco, O.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Simone, P.; Dean, C.-T.; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Déléage, N.; Demmer, M.; Derkach, D.; Deschamps, O.; Dettori, F.; Dey, B.; Di Canto, A.; Di Ruscio, F.; Dijkstra, H.; Dordei, F.; Dorigo, M.; Dosil Suárez, A.; Dovbnya, A.; Dreimanis, K.; Dufour, L.; Dujany, G.; Dungs, K.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Easo, S.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; El Rifai, I.; Elsasser, Ch.; Ely, S.; Esen, S.; Evans, H. M.; Evans, T.; Falabella, A.; Färber, C.; Farley, N.; Farry, S.; Fay, R.; Fazzini, D.; Ferguson, D.; Fernandez Albor, V.; Ferrari, F.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fiore, M.; Fiorini, M.; Firlej, M.; Fitzpatrick, C.; Fiutowski, T.; Fleuret, F.; Fohl, K.; Fontana, M.; Fontanelli, F.; Forshaw, D. C.; Forty, R.; Frank, M.; Frei, C.; Frosini, M.; Fu, J.; Furfaro, E.; Gallas Torreira, A.; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Gao, Y.; García Pardiñas, J.; Garra Tico, J.; Garrido, L.; Garsed, P. J.; Gascon, D.; Gaspar, C.; Gavardi, L.; Gazzoni, G.; Gerick, D.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gianı, S.; Gibson, V.; Girard, O. G.; Giubega, L.; Gligorov, V. V.; Göbel, C.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gotti, C.; Grabalosa Gándara, M.; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graverini, E.; Graziani, G.; Grecu, A.; Griffith, P.; Grillo, L.; Grünberg, O.; Gushchin, E.; Guz, Yu.; Gys, T.; Hadavizadeh, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hall, S.; Hamilton, B.; Han, X.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; He, J.; Head, T.; Heister, A.; Hennessy, K.; Henrard, P.; Henry, L.; Hernando Morata, J. A.; van Herwijnen, E.; Heß, M.; Hicheur, A.; Hill, D.; Hoballah, M.; Hombach, C.; Hongming, L.; Hulsbergen, W.; Humair, T.; Hushchyn, M.; Hussain, N.; Hutchcroft, D.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jaeger, A.; Jalocha, J.; Jans, E.; Jawahery, A.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Jurik, N.; Kandybei, S.; Kanso, W.; Karacson, M.; Karbach, T. M.; Karodia, S.; Kecke, M.; Kelsey, M.; Kenyon, I. R.; Kenzie, M.; Ketel, T.; Khairullin, E.; Khanji, B.; Khurewathanakul, C.; Kirn, T.; Klaver, S.; Klimaszewski, K.; Kolpin, M.; Komarov, I.; Koopman, R. F.; Koppenburg, P.; Kozeiha, M.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krokovny, P.; Kruse, F.; Krzemien, W.; Kucewicz, W.; Kucharczyk, M.; Kudryavtsev, V.; Kuonen, A. K.; Kurek, K.; Kvaratskheliya, T.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lambert, D.; Lanfranchi, G.; Langenbruch, C.; Langhans, B.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Lees, J.-P.; Lefèvre, R.; Leflat, A.; Lefrançois, J.; Lemos Cid, E.; Leroy, O.; Lesiak, T.; Leverington, B.; Li, Y.; Likhomanenko, T.; Lindner, R.; Linn, C.; Lionetto, F.; Liu, B.; Liu, X.; Loh, D.; Longstaff, I.; Lopes, J. H.; Lucchesi, D.; Lucio Martinez, M.; Luo, H.; Lupato, A.; Luppi, E.; Lupton, O.; Lusardi, N.; Lusiani, A.; Lyu, X.; Machefert, F.; Maciuc, F.; Maev, O.; Maguire, K.; Malde, S.; Malinin, A.; Manca, G.; Mancinelli, G.; Manning, P.; Mapelli, A.; Maratas, J.; Marchand, J. F.; Marconi, U.; Marin Benito, C.; Marino, P.; Marks, J.; Martellotti, G.; Martin, M.; Martinelli, M.; Martinez Santos, D.; Martinez Vidal, F.; Martins Tostes, D.; Massacrier, L. M.; Massafferri, A.; Matev, R.; Mathad, A.; Mathe, Z.; Matteuzzi, C.; Mauri, A.; Maurin, B.; Mazurov, A.; McCann, M.; McCarthy, J.; McNab, A.; McNulty, R.; Meadows, B.; Meier, F.; Meissner, M.; Melnychuk, D.; Merk, M.; Merli, A.; Michielin, E.; Milanes, D. A.; Minard, M.-N.; Mitzel, D. S.; Molina Rodriguez, J.; Monroy, I. A.; Monteil, S.; Morandin, M.; Morawski, P.; Mordà, A.; Morello, M. J.; Moron, J.; Morris, A. B.; Mountain, R.; Muheim, F.; Müller, D.; Müller, J.; Müller, K.; Müller, V.; Mussini, M.; Muster, B.; Naik, P.; Nakada, T.; Nandakumar, R.; Nandi, A.; Nasteva, I.; Needham, M.; Neri, N.; Neubert, S.; Neufeld, N.; Neuner, M.; Nguyen, A. D.; Nguyen-Mau, C.; Niess, V.; Nieswand, S.; Niet, R.; Nikitin, N.; Nikodem, T.; Novoselov, A.; O'Hanlon, D. P.; Oblakowska-Mucha, A.; Obraztsov, V.; Ogilvy, S.; Okhrimenko, O.; Oldeman, R.; Onderwater, C. J. G.; Osorio Rodrigues, B.; Otalora Goicochea, J. M.; Otto, A.; Owen, P.; Oyanguren, A.; Palano, A.; Palombo, F.; Palutan, M.; Panman, J.; Papanestis, A.; Pappagallo, M.; Pappalardo, L. L.; Pappenheimer, C.; Parker, W.; Parkes, C.; Passaleva, G.; Patel, G. D.; Patel, M.; Patrignani, C.; Pearce, A.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Perret, P.; Pescatore, L.; Petridis, K.; Petrolini, A.; Petruzzo, M.; Picatoste Olloqui, E.; Pietrzyk, B.; Pikies, M.; Pinci, D.; Pistone, A.; Piucci, A.; Playfer, S.; Plo Casasus, M.; Poikela, T.; Polci, F.; Poluektov, A.; Polyakov, I.; Polycarpo, E.; Popov, A.; Popov, D.; Popovici, B.; Potterat, C.; Price, E.; Price, J. D.; Prisciandaro, J.; Pritchard, A.; Prouve, C.; Pugatch, V.; Puig Navarro, A.; Punzi, G.; Qian, W.; Quagliani, R.; Rachwal, B.; Rademacker, J. H.; Rama, M.; Ramos Pernas, M.; Rangel, M. S.; Raniuk, I.; Raven, G.; Redi, F.; Reichert, S.; dos Reis, A. C.; Renaudin, V.; Ricciardi, S.; Richards, S.; Rihl, M.; Rinnert, K.; Rives Molina, V.; Robbe, P.; Rodrigues, A. B.; Rodrigues, E.; Rodriguez Lopez, J. A.; Rodriguez Perez, P.; Rogozhnikov, A.; Roiser, S.; Romanovsky, V.; Romero Vidal, A.; Ronayne, J. W.; Rotondo, M.; Ruf, T.; Ruiz Valls, P.; Saborido Silva, J. J.; Sagidova, N.; Saitta, B.; Salustino Guimaraes, V.; Sanchez Mayordomo, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santimaria, M.; Santovetti, E.; Sarti, A.; Satriano, C.; Satta, A.; Saunders, D. M.; Savrina, D.; Schael, S.; Schiller, M.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmelzer, T.; Schmidt, B.; Schneider, O.; Schopper, A.; Schubiger, M.; Schune, M.-H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Semennikov, A.; Sergi, A.; Serra, N.; Serrano, J.; Sestini, L.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Shires, A.; Siddi, B. G.; Silva Coutinho, R.; Silva de Oliveira, L.; Simi, G.; Sirendi, M.; Skidmore, N.; Skwarnicki, T.; Smith, E.; Smith, I. T.; Smith, J.; Smith, M.; Snoek, H.; Sokoloff, M. D.; Soler, F. J. P.; Soomro, F.; Souza, D.; Souza De Paula, B.; Spaan, B.; Spradlin, P.; Sridharan, S.; Stagni, F.; Stahl, M.; Stahl, S.; Stefkova, S.; Steinkamp, O.; Stenyakin, O.; Stevenson, S.; Stoica, S.; Stone, S.; Storaci, B.; Stracka, S.; Straticiuc, M.; Straumann, U.; Sun, L.; Sutcliffe, W.; Swientek, K.; Swientek, S.; Syropoulos, V.; Szczekowski, M.; Szumlak, T.; T'Jampens, S.; Tayduganov, A.; Tekampe, T.; Tellarini, G.; Teubert, F.; Thomas, C.; Thomas, E.; van Tilburg, J.; Tisserand, V.; Tobin, M.; Tolk, S.; Tomassetti, L.; Tonelli, D.; Topp-Joergensen, S.; Tournefier, E.; Tourneur, S.; Trabelsi, K.; Traill, M.; Tran, M. T.; Tresch, M.; Trisovic, A.; Tsaregorodtsev, A.; Tsopelas, P.; Tuning, N.; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vacca, C.; Vagnoni, V.; Valat, S.; Valenti, G.; Vallier, A.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vázquez Sierra, C.; Vecchi, S.; van Veghel, M.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Vesterinen, M.; Viaud, B.; Vieira, D.; Vieites Diaz, M.; Vilasis-Cardona, X.; Volkov, V.; Vollhardt, A.; Voong, D.; Vorobyev, A.; Vorobyev, V.; Voß, C.; de Vries, J. A.; Waldi, R.; Wallace, C.; Wallace, R.; Walsh, J.; Wang, J.; Ward, D. R.; Watson, N. K.; Websdale, D.; Weiden, A.; Whitehead, M.; Wicht, J.; Wilkinson, G.; Wilkinson, M.; Williams, M.; Williams, M. P.; Williams, M.; Williams, T.; Wilson, F. F.; Wimberley, J.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wraight, K.; Wright, S.; Wyllie, K.; Xie, Y.; Xu, Z.; Yang, Z.; Yin, H.; Yu, J.; Yuan, X.; Yushchenko, O.; Zangoli, M.; Zavertyaev, M.; Zhang, L.; Zhang, Y.; Zhelezov, A.; Zheng, Y.; Zhokhov, A.; Zhong, L.; Zhukov, V.; Zucchelli, S.; LHCb Collaboration
2016-06-01
Violations of C P T symmetry and Lorentz invariance are searched for by studying interference effects in B0 mixing and in Bs0 mixing. Samples of B0→J /ψ KS0 and Bs0→J /ψ K+K- decays are recorded by the LHCb detector in proton-proton collisions at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb-1 . No periodic variations of the particle-antiparticle mass differences are found, consistent with Lorentz invariance and C P T symmetry. Results are expressed in terms of the standard model extension parameter Δ aμ with precisions of O (10-15) and O (10-14) GeV for the B0 and Bs0 systems, respectively. With no assumption on Lorentz (non)invariance, the C P T -violating parameter z in the Bs0 system is measured for the first time and found to be R e (z ) =-0.022 ±0.033 ±0.005 and I m (z ) =0.004 ±0.011 ±0.002 , where the first uncertainties are statistical and the second systematic.
Minkowski spacetime and Lorentz invariance: The cart and the horse or two sides of a single coin?
NASA Astrophysics Data System (ADS)
Acuña, Pablo
2016-08-01
Michel Janssen and Harvey Brown have driven a prominent recent debate concerning the direction of an alleged arrow of explanation between Minkowski spacetime and Lorentz invariance of dynamical laws in special relativity. In this article, I critically assess this controversy with the aim of clarifying the explanatory foundations of the theory. First, I show that two assumptions shared by the parties-that the dispute is independent of issues concerning spacetime ontology, and that there is an urgent need for a constructive interpretation of special relativity-are problematic and negatively affect the debate. Second, I argue that the whole discussion relies on a misleading conception of the link between Minkowski spacetime structure and Lorentz invariance, a misconception that in turn sheds more shadows than light on our understanding of the explanatory nature and power of Einstein's theory. I state that the arrow connecting Lorentz invariance and Minkowski spacetime is not explanatory and unidirectional, but analytic and bidirectional, and that this analytic arrow grounds the chronogeometric explanations of physical phenomena that special relativity offers. The first goal of this article is to show that the dispute relies on a misleading overinterpretation of the relation between Minkowski structure and Lorentz invariance in special relativity, which in turn results in a misconception of the explanatory nature of Einstein's theory. I point out two problematic issues underlying the debate that have a significant negative import on its overall evaluation. More precisely, despite the authors' explicit comments to the contrary, I show that the discussion is knotted with the question of the ontology of spacetime: Janssen's view is connected to a form of substantivalism, whereas Brown's view assumes a form of relationism. I also show that the urgent demand for a constructive interpretation of special relativity that Janssen and Brown argue
A New Limit on Lorentz Invariance and Chromatic Dispersion Across the Universe from GRB 090510A
NASA Astrophysics Data System (ADS)
Nemiroff, Robert J.; Connolly, R.; Holmes, J.
2012-01-01
A high-energy, fast-variability time scale for Fermi-detected gamma-ray burst GRB 090510A is found that creates a new strictest upper limit on the energy dependence of the speed and dispersion of light across the universe. In particular, evidence is presented for variability at or below Δ t = 0.00136 for super-GeV photons, a factor of 10 more limiting than any time scale previously claimed for a GRB at GeV energies, including a previous limit reported by Abdo et al (2008). This variability derives from the duration of three separate closely-arriving photon groups prominent only in photon data above 1 GeV. One pulse pair has an energy difference of Δ E >/ 23.5 GeV. Coupled with a redshift of z >/ 0.897, the resulting limits on the differential speed of light and Lorentz invariance were found for a concordance cosmology. It was found that Δ c / c < 6.09 x 10-21, a limit consistent with, but slightly stronger than, a previous limit found for a GRB by Schaefer in 1999. Given a generic dispersion relation across the universe where the time delay is proportional to the photon energy to the first power, the variability translates into a dispersion strength of k1 < 1.38 x 10-5 sec Gpc-1 GeV-1. This limit results in an upper bound on dispersive effects created, for example, by dark energy, dark matter, or the spacetime foam of quantum gravity. This dispersion constraint also results in the most stringent lower limit yet claimed for the onset energy scale of quantum gravity: MQG c2 > 7.43 x 1021 GeV.
NASA Technical Reports Server (NTRS)
Vasileiou, V.; Jacholkowska, A.; Piron, F.; Bolmont, J.; Courturier, C.; Granot, J.; Stecker, Floyd William; Cohen-Tanugi, J.; Longo, F.
2013-01-01
We analyze the MeV/GeV emission from four bright Gamma-Ray Bursts (GRBs) observed by the Fermi-Large Area Telescope to produce robust, stringent constraints on a dependence of the speed of light in vacuo on the photon energy (vacuum dispersion), a form of Lorentz invariance violation (LIV) allowed by some Quantum Gravity (QG) theories. First, we use three different and complementary techniques to constrain the total degree of dispersion observed in the data. Additionally, using a maximally conservative set of assumptions on possible source-intrinsic spectral-evolution effects, we constrain any vacuum dispersion solely attributed to LIV. We then derive limits on the "QG energy scale" (the energy scale that LIV-inducing QG effects become important, E(sub QG)) and the coefficients of the Standard Model Extension. For the subluminal case (where high energy photons propagate more slowly than lower energy photons) and without taking into account any source-intrinsic dispersion, our most stringent limits (at 95% CL) are obtained from GRB 090510 and are E(sub QG,1) > 7.6 times the Planck energy (E(sub Pl)) and E(sub QG,2) > 1.3×10(exp 11) GeV for linear and quadratic leading order LIV-induced vacuum dispersion, respectively. These limits improve the latest constraints by Fermi and H.E.S.S. by a factor of approx. 2. Our results disfavor any class of models requiring E(sub QG,1) < or approx. E(sub Pl)
Comment on ''Subtleties of Lorentz invariance and Shapes of the Nucleon''
Franz Gross; G. Ramalho; M.T. Pena
2007-08-07
The paper on ''Subtleties of Lorentz invariance and Shapes of the Nucleon'' by Kvinikhidze and Miller (referred to as KM) was originally submitted as a comment on our manuscript ''A pure S-wave covariant model for the nucleon'' (referred to as GRP1). KM claimed that the definition of polarization states used in GRP1 was not covariant. Subsequently, GRP1 was rejected by the Physical Review (for reasons having nothing to do with the definition of the polarization states), the KM ''comment'' was accepted by Physical Review (now reclassified as a brief report), and we have nearly completed two new papers, one that is a substantial revision and replacement of GRP1 and another that applies these ideas to the {gamma}* + N {yields} {Delta} transition (we refer to these two papers collectively as GRP2). To add to the confusion, Kvinikhidze and Miller used the unpublished ''advisory report'' [prepared by one of us (FG) as part of the original review process] to revise their original draft. This advisory report contained a more complete discussion of our new definition of polarization states, a discussion not yet published anywhere (but included in more detail in GRP2, the papers we are preparing for publication). At this moment we find ourselves in the unusual position of being criticized for work that is either not yet published or exists only in a referee's report. The purposes of this comment are (i) to present the issues (referred to by KM but unpublished by us) in a coherent way that explains the physics, leaving a more complete discussion for GRP2, (ii) to answer the objections of KM, and (iii) to set the record straight (partly accomplished in this Introduction). The remainder of this comment is divided into three sections. In Sec. II, building on the physical intuition introduced in GRP1, we present a coherent discussion of wave functions and currents based on the new fixed-axis polarization vectors and show that they are covariant. In Sec. III we discuss one issue
NASA Astrophysics Data System (ADS)
Kislat, Fabian; Krawczynski, Henric
2017-04-01
Lorentz invariance is the fundamental symmetry of Einstein's theory of special relativity and has been tested to a great level of detail. However, theories of quantum gravity at the Planck scale indicate that Lorentz symmetry may be broken at that scale, motivating further tests. While the Planck energy is currently unreachable by experiment, tiny residual effects at attainable energies can become measurable when photons propagate over sufficiently large distances. The Standard-Model extension (SME) is an effective field-theory approach to describe low-energy effects of quantum gravity theories. Lorentz- and C P T -symmetry-violating effects are introduced by adding additional terms to the Standard-Model Lagrangian. These terms can be ordered by the mass dimension of the corresponding operator, and the leading terms of interest have dimension d =5 . Effects of these operators are a linear variation of the speed of light with photon energy, and a rotation of the linear polarization of photons quadratic in photon energy, as well as anisotropy. We analyze optical polarization data from 72 active galactic nuclei and GRBs and derive the first set of limits on all 16 coefficients of mass dimension d =5 of the SME photon sector. Our constraints imply a lower limit on the energy scale of quantum gravity of 1 06 times the Planck energy, severely limiting the phase space for any theory that predicts a rotation of the photon polarization quadratic in energy.
NASA Astrophysics Data System (ADS)
Célérier, Marie-Noëlle; Nottale, Laurent
2014-05-01
Owing to the non-differentiable nature of the theory of Scale Relativity, the emergence of complex wave functions, then of spinors and bi-spinors occurs naturally in its framework. The wave function is here a manifestation of the velocity field of geodesics of a continuous and non-differentiable (therefore fractal) space-time. In a first paper (Paper I), we have presented the general argument which leads to this result using an elaborate and more detailed derivation than previously displayed. We have therefore been able to show how the complex wave function emerges naturally from the doubling of the velocity field and to revisit the derivation of the non-relativistic Schrödinger equation of motion. In the present paper (Paper II), we deal with relativistic motion and detail the natural emergence of the bi-spinors from such first principles of the theory. Moreover, while Lorentz invariance has been up to now inferred from mathematical results obtained in stochastic mechanics, we display here a new and detailed derivation of the way one can obtain a Lorentz invariant expression for the expectation value of the product of two independent fractal fluctuation fields in the sole framework of the theory of Scale Relativity. These new results allow us to enhance the robustness of our derivation of the two main equations of motion of relativistic quantum mechanics (the Klein-Gordon and Dirac equations) which we revisit here at length.
Célérier, Marie-Noëlle; Nottale, Laurent E-mail: laurent.nottale@obspm.fr
2014-05-15
Owing to the non-differentiable nature of the theory of Scale Relativity, the emergence of complex wave functions, then of spinors and bi-spinors occurs naturally in its framework. The wave function is here a manifestation of the velocity field of geodesics of a continuous and non-differentiable (therefore fractal) space-time. In a first paper (Paper I), we have presented the general argument which leads to this result using an elaborate and more detailed derivation than previously displayed. We have therefore been able to show how the complex wave function emerges naturally from the doubling of the velocity field and to revisit the derivation of the non-relativistic Schrödinger equation of motion. In the present paper (Paper II), we deal with relativistic motion and detail the natural emergence of the bi-spinors from such first principles of the theory. Moreover, while Lorentz invariance has been up to now inferred from mathematical results obtained in stochastic mechanics, we display here a new and detailed derivation of the way one can obtain a Lorentz invariant expression for the expectation value of the product of two independent fractal fluctuation fields in the sole framework of the theory of Scale Relativity. These new results allow us to enhance the robustness of our derivation of the two main equations of motion of relativistic quantum mechanics (the Klein-Gordon and Dirac equations) which we revisit here at length.
Laemmerzahl, Claus; Macias, Alfredo; Mueller, Holger
2005-01-15
All quantum gravity approaches lead to small modifications in the standard laws of physics which in most cases lead to violations of Lorentz invariance. One particular example is the extended standard model (SME). Here, a general phenomenological approach for extensions of the Maxwell equations is presented which turns out to be more general than the SME and which covers charge nonconservation (CNC), too. The new Lorentz invariance violating terms cannot be probed by optical experiments but need, instead, the exploration of the electromagnetic field created by a point charge or a magnetic dipole. Some scalar tensor theories and higher dimensional brane theories predict CNC in four dimensions and some models violating special relativity have been shown to be connected with CNC. Its relation to the Einstein Equivalence Principle has been discussed. Because of this upcoming interest, the experimental status of electric charge conservation is reviewed. Up to now there seem to exist no unique tests of charge conservation. CNC is related to the precession of polarization, to a modification of the 1/r-Coulomb potential, and to a time dependence of the fine structure constant. This gives the opportunity to describe a dedicated search for CNC.
Search for Lorentz invariance and CPT violation with the MINOS far detector.
Adamson, P; Auty, D J; Ayres, D S; Backhouse, C; Barr, G; Barrett, W L; Bishai, M; Blake, A; Bock, G J; Boehnlein, D J; Bogert, D; Bower, C; Budd, S; Cavanaugh, S; Cherdack, D; Childress, S; Choudhary, B C; Coelho, J A B; Cobb, J H; Coleman, S J; Corwin, L; Cravens, J P; Cronin-Hennessy, D; Danko, I Z; de Jong, J K; Devenish, N E; Diwan, M V; Dorman, M; Escobar, C O; Evans, J J; Falk, E; Feldman, G J; Frohne, M V; Gallagher, H R; Gomes, R A; Goodman, M C; Gouffon, P; Gran, R; Grant, N; Grzelak, K; Habig, A; Harris, D; Harris, P G; Hartnell, J; Hatcher, R; Himmel, A; Holin, A; Huang, X; Hylen, J; Ilic, J; Irwin, G M; Isvan, Z; Jaffe, D E; James, C; Jensen, D; Kafka, T; Kasahara, S M S; Koizumi, G; Kopp, S; Kordosky, M; Krahn, Z; Kreymer, A; Lang, K; Lefeuvre, G; Ling, J; Litchfield, P J; Loiacono, L; Lucas, P; Mann, W A; Marshak, M L; Mayer, N; McGowan, A M; Mehdiyev, R; Meier, J R; Messier, M D; Michael, D G; Miller, J L; Miller, W H; Mishra, S R; Mitchell, J; Moore, C D; Mualem, L; Mufson, S; Musser, J; Naples, D; Nelson, J K; Newman, H B; Nichol, R J; Oliver, W P; Orchanian, M; Paley, J; Patterson, R B; Patzak, T; Pawloski, G; Pearce, G F; Pittam, R; Plunkett, R K; Ratchford, J; Raufer, T M; Rebel, B; Rodrigues, P A; Rosenfeld, C; Rubin, H A; Ryabov, V A; Sanchez, M C; Saoulidou, N; Schneps, J; Schreiner, P; Semenov, V K; Shanahan, P; Smart, W; Sousa, A; Strait, M; Tagg, N; Talaga, R L; Thomas, J; Thomson, M A; Tinti, G; Toner, R; Tzanakos, G; Urheim, J; Vahle, P; Viren, B; Weber, A; Webb, R C; White, C; Whitehead, L; Wojcicki, S G; Wright, D M; Yang, T; Zois, M; Zwaska, R
2010-10-08
We searched for a sidereal modulation in the MINOS far detector neutrino rate. Such a signal would be a consequence of Lorentz and CPT violation as described by the standard-model extension framework. It also would be the first detection of a perturbative effect to conventional neutrino mass oscillations. We found no evidence for this sidereal signature, and the upper limits placed on the magnitudes of the Lorentz and CPT violating coefficients describing the theory are an improvement by factors of 20-510 over the current best limits found by using the MINOS near detector.
Limits on Lorentz Invariance Violation from Coulomb Interactions in Nuclei and Atoms.
Flambaum, V V; Romalis, M V
2017-04-07
Anisotropy in the speed of light that has been constrained by Michelson-Morley-type experiments also generates anisotropy in the Coulomb interactions. This anisotropy can manifest itself as an energy anisotropy in nuclear and atomic experiments. Here the experimental limits on Lorentz violation in _{10}^{21}Ne are used to improve the limits on Lorentz symmetry violations in the photon sector, namely, the anisotropy of the speed of light and the Coulomb interactions, by 7 orders of magnitude in comparison with previous experiments: the speed of light is isotropic to a part in 10^{28}.
Effects of the Lorentz Invariance Violation on Coulomb Interactions in Nuclei and Atoms
NASA Astrophysics Data System (ADS)
Flambaum, V. V.; Romalis, M. V.
2017-04-01
Anisotropy in the speed of light that has been constrained by Michelson-Morley-type experiments also generates anisotropy in the Coulomb interactions. This anisotropy can manifest itself as an energy anisotropy in nuclear and atomic experiments. Here the experimental limits on Lorentz violation in Ne2110 are used to improve the limits on Lorentz symmetry violations in the photon sector, namely, the anisotropy of the speed of light and the Coulomb interactions, by 7 orders of magnitude in comparison with previous experiments: the speed of light is isotropic to a part in 10-28.
Test of Lorentz Invariance with a RB-21NE Comagnetometer at the South Pole
NASA Astrophysics Data System (ADS)
Smiciklas, M. A.; Romalis, M. V.
2014-01-01
Atomic spin comagnetometers are among the most sensitive devices for testing Lorentz symmetry of fermions. In Princeton, we have used our rotating comagnetometer to set the most stringent limits on CPT-odd and CPT-even Lorentz violating effects in neutrons. However, gyroscopic pickup of the Earth's rotation represents a significant systematic effect limiting sensitivity. To suppress this systematic, we have installed a Rb-21Ne comagnetometer at the Amundsen-Scott South Pole Station with data collection being performed over the course of the austral winter.
A Search for Lorentz Invariance and CPT Violation with the MINOS Far Detector
Adamson, P.; Auty, D.J.; Ayres, D.S.; Backhouse, C.; Barr, G.; Barrett, W.L.; Bishai, M.; Blake, A.; Bock, G.J.; Boehnlein, D.J.; Bogert, D.; /Fermilab /Indiana U.
2010-07-01
We searched for a sidereal modulation in the MINOS far detector neutrino rate. Such a signal would be a consequence of Lorentz and CPT violation as described by the Standard-Model Extension framework. It also would be the first detection of a perturbative effect to conventional neutrino mass oscillations. We found no evidence for this sidereal signature and the upper limits placed on the magnitudes of the Lorentz and CPT violating coefficients describing the theory are an improvement by factors of 20-510 over the current best limits found using the MINOS near detector.
Testing Lorentz invariance and CPT conservation with NuMI neutrinos in the MINOS near detector.
Adamson, P; Andreopoulos, C; Arms, K E; Armstrong, R; Auty, D J; Ayres, D S; Baller, B; Barr, G; Barrett, W L; Becker, B R; Belias, A; Bernstein, R H; Bhattacharya, D; Bishai, M; Blake, A; Bock, G J; Boehm, J; Boehnlein, D J; Bogert, D; Bower, C; Buckley-Geer, E; Cavanaugh, S; Chapman, J D; Cherdack, D; Childress, S; Choudhary, B C; Coleman, S J; Culling, A J; de Jong, J K; Diwan, M V; Dorman, M; Dytman, S A; Escobar, C O; Evans, J J; Falk Harris, E; Feldman, G J; Frohne, M V; Gallagher, H R; Goodman, M C; Gouffon, P; Gran, R; Grashorn, E W; Grossman, N; Grzelak, K; Habig, A; Harris, D; Harris, P G; Hartnell, J; Hatcher, R; Heller, K; Himmel, A; Holin, A; Hylen, J; Irwin, G M; Ishitsuka, M; Jaffe, D E; James, C; Jensen, D; Kafka, T; Kasahara, S M S; Kim, J J; Koizumi, G; Kopp, S; Kordosky, M; Koskinen, D J; Kreymer, A; Kumaratunga, S; Lang, K; Ling, J; Litchfield, P J; Litchfield, R P; Loiacono, L; Lucas, P; Ma, J; Mann, W A; Marshak, M L; Marshall, J S; Mayer, N; McGowan, A M; Meier, J R; Messier, M D; Metelko, C J; Michael, D G; Miller, J L; Miller, W H; Mishra, S R; Moore, C D; Morfín, J; Mualem, L; Mufson, S; Murgia, S; Musser, J; Naples, D; Nelson, J K; Newman, H B; Nichol, R J; Nicholls, T C; Ochoa-Ricoux, J P; Oliver, W P; Ospanov, R; Paley, J; Paolone, V; Para, A; Patzak, T; Pavlović, Z; Pawloski, G; Pearce, G F; Peck, C W; Petyt, D A; Pittam, R; Plunkett, R K; Rahaman, A; Rameika, R A; Raufer, T M; Rebel, B; Reichenbacher, J; Rodrigues, P A; Rosenfeld, C; Rubin, H A; Sanchez, M C; Saoulidou, N; Schneps, J; Schreiner, P; Shanahan, P; Smart, W; Sousa, A; Speakman, B; Stamoulis, P; Strait, M; Tagg, N; Talaga, R L; Tavera, M A; Thomas, J; Thompson, J; Thomson, M A; Thron, J L; Tinti, G; Tzanakos, G; Urheim, J; Vahle, P; Viren, B; Watabe, M; Weber, A; Webb, R C; Wehmann, A; West, N; White, C; Wojcicki, S G; Yang, T; Zois, M; Zhang, K; Zwaska, R
2008-10-10
A search for a sidereal modulation in the MINOS near detector neutrino data was performed. If present, this signature could be a consequence of Lorentz and CPT violation as predicted by the effective field theory called the standard-model extension. No evidence for a sidereal signal in the data set was found, implying that there is no significant change in neutrino propagation that depends on the direction of the neutrino beam in a sun-centered inertial frame. Upper limits on the magnitudes of the Lorentz and CPT violating terms in the standard-model extension lie between 10(-4) and 10(-2) of the maximum expected, assuming a suppression of these signatures by a factor of 10(-17).
Mufson, Stuart; Rebel, Brian
2014-01-01
We searched for a sidereal modulation in the rate of neutrinos observed by the MINOS far detector. The detection of these signals could be a signature of neutrino-antineutrino mixing due to Lorentz and CPT violation as described by the Standard-Model Extension framework. We found no evidence for these sidereal signals and we placed limits on the coefficients in this theory describing the effect.
Pan, Yu; Gong, Yungui; Cao, Shuo; Zhu, Zong-Hong; Gao, He
2015-07-20
In the quantum theory of gravity, for photons we expect the Lorentz Invariance Violation (LIV) and the modification of the dispersion relation between energy and momentum. The effect of the energy-dependent velocity due to the modified dispersion relation for photons was studied in the standard cosmological context by using a sample of gamma-ray bursts (GRBs). In this paper we mainly discuss the possible LIV effect of using different cosmological models for the accelerating universe. Due to the degeneracies among model parameters, the GRBs’ time delay data are combined with the cosmic microwave background data from the Planck first-year release, the baryon acoustic oscillation data at six different redshifts, and Union2 Type Ia supernovae data to constrain both the model parameters and the LIV effect. We find no evidence of the LIV.
NASA Astrophysics Data System (ADS)
MAGIC Collaboration; Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Arcaro, C.; Babić, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Berti, A.; Bhattacharyya, W.; Biasuzzi, B.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Carosi, R.; Carosi, A.; Chatterjee, A.; Colak, S. M.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Cumani, P.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Lotto, B.; de Oña Wilhelmi, E.; Di Pierro, F.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher Glawion, D.; Elsaesser, D.; Engelkemeier, M.; Fallah Ramazani, V.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Font, L.; Fruck, C.; Galindo, D.; García López, R. J.; Garczarczyk, M.; Garrido, D.; Gaug, M.; Giammaria, P.; Godinović, N.; Gora, D.; Guberman, D.; Hadasch, D.; Hahn, A.; Hassan, T.; Hayashida, M.; Herrera, J.; Hose, J.; Hrupec, D.; Inada, T.; Ishio, K.; Konno, Y.; Kubo, H.; Kushida, J.; Kuveždić, D.; Lelas, D.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; Maggio, C.; Majumdar, P.; Makariev, M.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Minev, M.; Mirzoyan, R.; Moralejo, A.; Moreno, V.; Moretti, E.; Neustroev, V.; Niedzwiecki, A.; Nievas Rosillo, M.; Nilsson, K.; Ninci, D.; Nishijima, K.; Noda, K.; Nogués, L.; Paiano, S.; Palacio, J.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Pedaletti, G.; Peresano, M.; Perri, L.; Persic, M.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Garcia, J. R.; Reichardt, I.; Rhode, W.; Ribó, M.; Rico, J.; Righi, C.; Saito, T.; Satalecka, K.; Schroeder, S.; Schweizer, T.; Shore, S. N.; Sitarek, J.; Šnidarić, I.; Sobczynska, D.; Stamerra, A.; Strzys, M.; Surić, T.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Torres, D. F.; Torres-Albà, N.; Treves, A.; Vanzo, G.; Vazquez Acosta, M.; Vovk, I.; Ward, J. E.; Will, M.; Zarić, D.
2017-09-01
Spontaneous breaking of Lorentz symmetry at energies on the order of the Planck energy or lower is predicted by many quantum gravity theories, implying non-trivial dispersion relations for the photon in vacuum. Consequently, gamma-rays of different energies, emitted simultaneously from astrophysical sources, could accumulate measurable differences in their time of flight until they reach the Earth. Such tests have been carried out in the past using fast variations of gamma-ray flux from pulsars, and more recently from active galactic nuclei and gamma-ray bursts. We present new constraints studying the gamma-ray emission of the galactic Crab Pulsar, recently observed up to TeV energies by the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) collaboration. A profile likelihood analysis of pulsar events reconstructed for energies above 400 GeV finds no significant variation in arrival time as their energy increases. Ninety-five percent CL limits are obtained on the effective Lorentz invariance violating energy scale at the level of {E}{{QG}1}> 5.5× {10}17 {GeV} (4.5× {10}17 {GeV}) for a linear, and {E}{{QG}2}> 5.9× {10}10 {GeV} (5.3× {10}10 {GeV}) for a quadratic scenario, for the subluminal and the superluminal cases, respectively. A substantial part of this study is dedicated to calibration of the test statistic, with respect to bias and coverage properties. Moreover, the limits take into account systematic uncertainties, which are found to worsen the statistical limits by about 36%–42%. Our constraints would have been much more stringent if the intrinsic pulse shape of the pulsar between 200 GeV and 400 GeV was understood in sufficient detail and allowed inclusion of events well below 400 GeV.
NASA Astrophysics Data System (ADS)
Sidharth, B. G.; Das, Abhishek; Roy, Arka Dev
2016-05-01
This paper deals with the violation of Lorentz symmetry. The approach is based on Compton scattering which becomes modified due to a modified dispersion relation arising from a minimum spacetime cut off as in modern Quantum Gravity approaches. With this amendment, we find that two high-energy rays of different energies develop a time-lag. This time separation becomes prominent when the energies of the considered photons is ≥ 1 GeV. Extending our approach to gamma rays of cosmic origin we predict that they undergo innumerable such scattering processes before reaching us. Therefore, it accounts for the time-lag phenomena of gamma ray bursts ( GRB)'s which have been claimed to be observed. Also, we find that resorting to the modified Snyder-Sidharth Hamiltonian it is possible to extend the GZK cut off beyond its normal limit, 1020 eV. Some observations of ultra high energy cosmic rays support this. This extends the limits of special theory of relativity.
NASA Astrophysics Data System (ADS)
Connolly, Ryan; Nemiroff, R. J.; Holmes, J.
2012-01-01
High-energy photon data from the Fermi LAT provides an excellent source for constraining Lorentz invariance and limiting photon dispersion across the Universe. Photon groupings at the super-GeV level in Fermi gamma-ray bursts suggest upper limits on the time scales for dispersion over cosmological distances. A computational Monte Carlo approach allows us to find conservative limits on dispersion time scales at various levels of significance. By generating many random sets of "photons" with the same conditions as a chosen LAT data set, any number of small time scales can be tested and compared between the random bursts and the actual burst to observe the uniqueness of this burst within a desired tolerance or significance level. Similarly, applying a method of gap multiplication to both actual and Monte Carlo cases provides another quantitative evaluation of the overall bunching reminiscent of entropy. We have developed such algorithms using GRB 090510A as a focused case due to the presence of heavily bunched structure at energies above 1 GeV. Bunching time scales in GRB 090510A were calculated at a 3-sigma significance level with both numerical approaches and the resulting limits on dispersion and variance in photon travel speeds are the strongest to date. The application of such algorithms to many GRBs - above 1 GeV or otherwise - not only allows for a broader overview of photon dispersion time scales but also easily singles out unique cases with significant bunching at higher energies.
NASA Astrophysics Data System (ADS)
Pressler, David E.
2012-03-01
A great discrepancy exists - the speed of light and the neutrino speed must be identical; as indicated by supernova1987A; yet, OPERA predicts faster-than-light neutrinos. Einstein's theories are based on the invariance of the speed of light, and no privileged Galilean frame of reference exists. Both of these hypotheses are in error and must be reconciled in order to solve the dilemma. The Michelson-Morley Experiment was misinterpreted - my Neoclassical Theory postulates that BOTH mirrors of the interferometer physically and absolutely move towards its center. The result is a three-directional-Contraction, (x, y, z axis), an actual distortion of space itself; a C-Space condition. ``PRESSLER'S LAW OF C-SPACE: The speed of light, c, will always be measured the same speed in all three directions (˜300,000 km/sec), in ones own inertial reference system, and will always be measured as having a different speed in all other inertial frames which are at a different kinetic energy level or at a location with a different strength gravity field'' Thus, the faster you go, motion, or the stronger the gravity field the smaller you get in all three directions. OPERA results are explained; at the surface of Earth, the strength of gravity field is at maximum -- below the earth's surface, time and space is less distorted; therefore, time is absolutely faster accordingly. Reference OPERA's preprint: Neutrino's faster time-effect due to altitude difference; (10-13ns) x c (299792458m) = 2.9 x 10-5 m/ns x distance (730085m) + 21.8m.) This is consistent with the OPERA result.
NASA Astrophysics Data System (ADS)
Holmes, Justin; Nemiroff, R. J.; Connolly, R.
2012-01-01
Statistical bunching of super-GeV photons from Fermi gamma ray burst 090510A is used to derive a new strict upper limit on the energy dependence of speed and dispersion of light across the universe. Photons over 1 GeV from four GRBs are selected within an energy dependent 2σ solid angle from the GRB center. In particular, bunched photons in 090510A have a significantly low Δ t which indicates variability below 0.00136 seconds. This extremely short Δ t is supported by statistical comparison using a modified correlation function of bunched photons with the natural time scale of photon arrival times throughout the burst. Δ E is observed in one photon pair to be close to 23.5 GeV. These parameters combined with a known redshift of z >/ 0.897 were used to compute a limiting dispersion relation for Lorentz-invariance-violating effects. This new limit of Δ c / c < 6.09 x 10-21 is consistent, but stronger than the previous limits set by Schaeffer in 1999 for a different GRB. Specific limits in the cases of Δ t \\propto Δ E and Δ t \\propto Δ E2 were computed using the most conservative values for parameters at their 2σ limits. These relations correspond to dispersion which may be due to dark energy, dark matter, or the foaminess of spacetime predicted by quantum gravity. In the specific case of quantum gravity, limits on photon dispersion of this type are calculated to be M1 c2 > 7.43 x $1021 GeV and M2 c2 > 7.13 x 1011 GeV. These results are the most stringent limits yet claimed by several orders of magnitude, primarily supported by a strong Δ t.
Vasileiou, V.; Stecker, F. W.; Cohen-Tanugi, J.
2013-06-04
For this research, we analyze the MeV/GeV emission from four bright gamma-ray bursts (GRBs) observed by the Fermi Large Area Telescope to produce robust, stringent constraints on a dependence of the speed of light in vacuo on the photon energy (vacuum dispersion), a form of Lorentz invariance violation (LIV) allowed by some quantum gravity (QG) theories. First, we use three different and complementary techniques to constrain the total degree of dispersion observed in the data. Additionally, using a maximally conservative set of assumptions on possible source-intrinsic, spectral-evolution effects, we constrain any vacuum dispersion solely attributed to LIV. We then derive limits on the QG energy scale (the energy scale where LIV-inducing QG effects become strong, E_{QG}) and the coefficients of the Standard Model Extension. For the subluminal case (where high-energy photons propagate more slowly than lower-energy photons) and without taking into account any source-intrinsic dispersion, our most stringent limits (at 95% C.L.) are obtained from GRB 090510 and are E_{QG,1} > 7.6 times the Planck energy (E_{Pl}) and E_{QG,2} > 1.3 × 10^{11} GeV for linear and quadratic leading-order LIV-induced vacuum dispersion, respectively. In conclusion, these limits improve the latest constraints by Fermi and H.E.S.S. by a factor of ~2 . Our results disfavor any class of models requiring E_{QG,1} ≲ E_{Pl} .
NASA Astrophysics Data System (ADS)
Lorentz, Matthias; Brun, Pierre
2017-03-01
Some extensions to the Standard Model lead to the introduction of Lorentz symmetry breaking terms, expected to induce deviations from Lorentz symmetry around the Planck scale. A parameterization of effects due to Lorentz invariance violation (LIV) can be introduced by adding an effective term to the photon dispersion relation. This affects the kinematics of electron-positron pair creation by TeV γ rays on the extragalactic background light (EBL) and translates into modifications of the standard EBL opacity for the TeV photon spectra of extragalactic sources. Exclusion limits are presented, obtained with the spectral analysis of H.E.S.S. observations taken on the blazar Mrk 501 during the exceptional 2014 flare. The energy spectrum, extending very significantly above 10 TeV, allows to place strong limits on LIV in the photon sector at the level of the Planck energy scale for linear perturbations in the photon dispersion relation, and provides the strongest constraints presently for the case of quadratic perturbations.
NASA Astrophysics Data System (ADS)
Matsuki, T.; Seo, K.
2007-12-01
Succeeding in predicting 0^+ and 1^+ states of D and D_s heavy mesons with our semi-relativistic quark potential model, we examine a method for constructing Lorentz-invariant scattering amplitudes and/or decay widths and develop a formulation to calculate Lorentz-boosted ones given the rest-frame wave functions in our model. To illustrate the effectiveness of our method, we apply the formulation to the problem of calculating the semileptonic weak form factors from the rest-frame wave functions of heavy mesons and numerically calculate the dynamical 1/m_Q corrections to those for the process bar B → D^{(*)}ℓbarν based on our model of heavy mesons. It is shown that nonvanishing expressions for ρ_1(ω) = ρ_2(ω) and ρ_3(ω) = ρ_4(ω)= 0 are obtained in a special Lorentz frame, where ρ_i(ω) are the parameters used in the Neubert-Rieckert decomposition of form factors. Various values of form factors are estimated. These values are compatible with recent experimental data as well as other theoretical calculations.
Murase, Kohta
2009-08-21
Detecting neutrinos and photons is crucial to identifying the sources of ultrahigh-energy cosmic rays (UHECRs), especially for transient sources. We focus on ultrahigh-energy gamma-ray emission from transient sources such as gamma-ray bursts, since >EeV gamma rays can be more direct evidence of UHECRs than approximately PeV neutrinos and GeV-TeV gamma rays. We demonstrate that coincident detections of approximately 1-100 events can be expected by current and future UHECR detectors such as Auger and JEM-EUSO, and the detection probability can be higher than that of neutrinos for nearby transient sources at < or approximately equal to 50-100 Mpc. They may be useful for constraining the uncertain cosmic radio background as well as knowing the source properties and maximum energy of UHECRs. They can also give us more than 10(4) times stronger limits on the Lorentz-invariance violation than current constraints.
Allmendinger, F; Heil, W; Karpuk, S; Kilian, W; Scharth, A; Schmidt, U; Schnabel, A; Sobolev, Yu; Tullney, K
2014-03-21
We report on the search for a CPT- and Lorentz-invariance-violating coupling of the He3 and Xe129 nuclear spins (each largely determined by a valence neutron) to posited background tensor fields that permeate the Universe. Our experimental approach is to measure the free precession of nuclear spin polarized He3 and Xe129 atoms in a homogeneous magnetic guiding field of about 400 nT using LTC SQUIDs as low-noise magnetic flux detectors. As the laboratory reference frame rotates with respect to distant stars, we look for a sidereal modulation of the Larmor frequencies of the colocated spin samples. As a result we obtain an upper limit on the equatorial component of the background field interacting with the spin of the bound neutron b(⊥)(n)<8.4 × 10(-34) GeV (68% C.L.). Our result improves our previous limit (data measured in 2009) by a factor of 30 and the world's best limit by a factor of 4.
From noncommutative spacetimes to Lorentz symmetry violation
NASA Astrophysics Data System (ADS)
Schreck, M.
2014-11-01
The current article provides a brief review on noncommutative spacetimes in light of Lorentz invariance violation and especially on how these models are linked to the Lorentz- violating Standard-Model Extension. By embedding a general noncommutative spacetime with a constant background tensor into the Standard-Model Extension, a couple of implications are drawn on Lorentz violation in such models.
On Lorentz Transformations in Symplectic Deformations
Cuesta, R.; Sabido, M.; Guzman, W.
2010-07-12
In this paper we study noncommutative Lorentz transformations using symplectic deformations. In this framework we define an infinitesimal line element that is invariant under this noncommutative Lorentz transformations. Using the symplectic geometry formalism, we find that noncommutative Lorentz transformations intertwine the canonical momentums with canonical position coordinates.
NASA Astrophysics Data System (ADS)
Wei, Jun-Jie; Wu, Xue-Feng; Gao, He; Mészáros, Peter
2016-08-01
Five TeV neutrino events weakly correlated with five gamma-ray bursts (GRBs) were detected recently by IceCube. This work is an attempt to show that if the GRB identifications are verified, the observed time delays between the TeV neutrinos and gamma-ray photons from GRBs provide attractive candidates for testing fundamental physics with high accuracy. Based on the assumed associations between the TeV neutrinos and GRBs, we find that the limiting velocity of the neutrinos is equal to that of photons to an accuracy of ~ 1.9 × 10-15 - 2.5 × 10-18, which is about 104 - 107 times better than the constraint obtained with the neutrino possibly from a blazar flare. In addition, we set the most stringent limits up to date on the energy scale of quantum gravity for both the linear and quadratic violations of Lorentz invariance, namely EQG, 1 > 6.3 × 1018 - 1.5 × 1021 GeV and EQG, 2 > 2.0 × 1011 - 4.2 × 1012 GeV, which are essentially as good as or are an improvement of one order of magnitude over the results previously obtained by the GeV photons of GRB 090510 and the PeV neutrino from a blazar flare. Assuming that the Shapiro time delay is caused by the gravitational potential of the Laniakea supercluster of galaxies, we also place the tightest limits to date on Einstein's weak equivalence principle through the relative differential variations of the parameterized post-Newtonian parameter γ values for two different species of particles (i.e., neutrinos and photons), yielding Δγ ~ 10-11 - 10-13. However, it should be emphasized again that these limits here obtained are at best forecast of what could be achieved if the GRB/neutrino correlations would be finally confirmed.
Lorentz-invariant Bell's inequality
Kim, Won Tae; Son, Edwin J.
2005-01-01
We study Bell's inequality in relation to the Einstein-Podolsky-Rosen paradox in the relativistic regime. For this purpose, a relativistically covariant analysis is used in the calculation of the Bell's inequality, which results in the maximally violated Bell's inequality in any reference frame.
Massive photons and Lorentz violation
NASA Astrophysics Data System (ADS)
Cambiaso, Mauro; Lehnert, Ralf; Potting, Robertus
2012-04-01
All quadratic translation- and gauge-invariant photon operators for Lorentz breakdown are included into the Stueckelberg Lagrangian for massive photons in a generalized Rξ gauge. The corresponding dispersion relation and tree-level propagator are determined exactly, and some leading-order results are derived. The question of how to include such Lorentz-violating effects into a perturbative quantum-field expansion is addressed. Applications of these results within Lorentz-breaking quantum-field theories include the regularization of infrared divergences as well as the free propagation of massive vector bosons.
Alternative theories of gravity and Lorentz violation
NASA Astrophysics Data System (ADS)
Xu, Rui; Foster, Joshua; Kostelecky, V. Alan
2017-01-01
General relativity has achieved many successes, including the prediction of experimental results. However, its incompatibility with quantum theory remains an obstacle. By extending the foundational properties of general relativity, alternative theories of gravity can be constructed. In this talk, we focus on fermion couplings in the weak-gravity limit of certain alternative theories of gravity. Under suitable experimental circumstances, some of these couplings match terms appearing in the gravitational SME, which is a general framework describing violations of local Lorentz invariance. Existing limits on Lorentz violation can therefore be used to constrain certain Lorentz-invariant alternative theories of gravity.
NASA Astrophysics Data System (ADS)
H.E.S.S. Collaboration; Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Barnacka, A.; Barres de Almeida, U.; Bazer-Bachi, A. R.; Becherini, Y.; Becker, J.; Behera, B.; Bernlöhr, K.; Bochow, A.; Boisson, C.; Bolmont, J.; Bordas, P.; Borrel, V.; Brucker, J.; Brun, F.; Brun, P.; Bühler, R.; Bulik, T.; Büsching, I.; Carrigan, S.; Casanova, S.; Cerruti, M.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Chounet, L.-M.; Clapson, A. C.; Coignet, G.; Conrad, J.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; Drury, L. O.'C.; Dubois, F.; Dubus, G.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Farnier, C.; Fegan, S.; Feinstein, F.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Füßling, M.; Gabici, S.; Gallant, Y. A.; Gast, H.; Gérard, L.; Gerbig, D.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Goret, P.; Göring, D.; Hague, J. D.; Hampf, D.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hoffmann, A.; Hofmann, W.; Hofverberg, P.; Horns, D.; Jacholkowska, A.; de Jager, O. C.; Jahn, C.; Jamrozy, M.; Jung, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Keogh, D.; Kerschhaggl, M.; Khangulyan, D.; Khélifi, B.; Klochkov, D.; Kluźniak, W.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Laffon, H.; Lamanna, G.; Lenain, J.-P.; Lennarz, D.; Lohse, T.; Lopatin, A.; Lu, C.-C.; Marandon, V.; Marcowith, A.; Masbou, J.; Maurin, D.; Maxted, N.; McComb, T. J. L.; Medina, M. C.; Méhault, J.; Moderski, R.; Moulin, E.; Naumann, C. L.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nekrassov, D.; Nguyen, N.; Nicholas, B.; Niemiec, J.; Nolan, S. J.; Ohm, S.; Olive, J.-F.; de Oña Wilhelmi, E.; Opitz, B.; Ostrowski, M.; Panter, M.; Paz Arribas, M.; Pedaletti, G.; Pelletier, G.; Petrucci, P.-O.; Pita, S.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raue, M.; Rayner, S. M.; Reimer, A.; Reimer, O.; Renaud, M.; de Los Reyes, R.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Ruppel, J.; Ryde, F.; Sahakian, V.; Santangelo, A.; Schlickeiser, R.; Schöck, F. M.; Schönwald, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Shalchi, A.; Sikora, M.; Skilton, J. L.; Sol, H.; Spengler, G.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Sushch, I.; Szostek, A.; Tam, P. H.; Tavernet, J.-P.; Terrier, R.; Tibolla, O.; Tluczykont, M.; Valerius, K.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Vialle, J. P.; Viana, A.; Vincent, P.; Vivier, M.; Völk, H. J.; Volpe, F.; Vorobiov, S.; Vorster, M.; Wagner, S. J.; Ward, M.; Wierzcholska, A.; Zajczyk, A.; Zdziarski, A. A.; Zech, A.; Zechlin, H.-S.; H.E.S.S. Collaboration
2011-04-01
Several models of Quantum Gravity predict Lorentz Symmetry breaking at energy scales approaching the Planck scale (˜1019 GeV). With present photon data from the observations of distant astrophysical sources, it is possible to constrain the Lorentz Symmetry breaking linear term in the standard photon dispersion relations. Gamma Ray Bursts (GRB) and flaring Active Galactic Nuclei (AGN) are complementary to each other for this purpose, since they are observed at different distances in different energy ranges and with different levels of variability. Following a previous publication of the High Energy Stereoscopic System (H.E.S.S.) collaboration [1], a more sensitive event-by-event method consisting of a likelihood fit is applied to PKS 2155-304 flare data of MJD 53944 (July 28, 2006) as used in the previous publication. The previous limit on the linear term is improved by a factor of ˜3 up to MQGl>2.1×1018 GeV and is currently the best result obtained with blazars. The sensitivity to the quadratic term is lower and provides a limit of MQGq> 6.4 × 1010 GeV, which is the best value obtained so far with an AGN and similar to the best limits obtained with GRB.
Lorentz Covariant Distributions with Spectral Conditions
Zinoviev, Yury M.
2007-11-14
The properties of the vacuum expectation values of products of the quantum fields are formulated in the book [1]. The vacuum expectation values of quantum fields products would be the Fourier transforms of the Lorentz covariant tempered distributions with supports in the product of the closed upper light cones. Lorentz invariant distributions are studied in the papers [2]--[4]. The authors of these papers wanted to describe Lorentz invariant distributions in terms of distributions given on the Lorentz group orbit space. This orbit space has a complicated structure. It is noted [5] that a tempered distribution with support in the closed upper light cone may be represented as the action of the wave operator in some power on a differentiable function with support in the closed upper light cone. For the description of the Lorentz covariant differentiable functions the boundary of the closed upper light cone is not important. The measure of this boundary is zero.
Fresnel formulas as Lorentz transformations
Monzon; Sanchez-Soto
2000-08-01
From a matrix formulation of the boundary conditions we obtain the fundamental invariant for an interface and a remarkably simple factorization of the interface matrix, which enables us to express the Fresnel coefficients in a new and compact form. This factorization allows us to recast the action of an interface between transparent media as a hyperbolic rotation. By exploiting the local isomorphism between SL(2, C) and the (3 + 1)-dimensional restricted Lorentz group SO(3, 1), we construct the equivalent Lorentz transformation that describes any interface.
Statistical mechanics and Lorentz violation
NASA Astrophysics Data System (ADS)
Colladay, Don; McDonald, Patrick
2004-12-01
The theory of statistical mechanics is studied in the presence of Lorentz-violating background fields. The analysis is performed using the Standard-Model Extension (SME) together with a Jaynesian formulation of statistical inference. Conventional laws of thermodynamics are obtained in the presence of a perturbed hamiltonian that contains the Lorentz-violating terms. As an example, properties of the nonrelativistic ideal gas are calculated in detail. To lowest order in Lorentz violation, the scalar thermodynamic variables are only corrected by a rotationally invariant combination of parameters that mimics a (frame dependent) effective mass. Spin-couplings can induce a temperature-independent polarization in the classical gas that is not present in the conventional case. Precision measurements in the residual expectation values of the magnetic moment of Fermi gases in the limit of high temperature may provide interesting limits on these parameters.
Supersymmetry and Lorentz Violation in 5D
Garcia-Aguilar, J. D.; Perez-Lorenzana, A.; Pedraza-Ortega, O.
2011-10-14
We present a study for a Supersymmetric field theory with Lorentz-Violation terms in 5D. We perform the analysis in the context of the Berger-Kostelecky model (BK), adding one compactified dimension that explicitly breaks the Lorentz invariance. We introduce terms that encode this breaking, and find non trivial restrictions over boundary conditions of fields that one needs to close the supersymmetric algebra.
Supersymmetry and Lorentz Violation in 5D
NASA Astrophysics Data System (ADS)
García-Aguilar, J. D.; Pérez-Lorenzana, A.; Pedraza-Ortega, O.
2011-10-01
We present a study for a Supersymmetric field theory with Lorentz-Violation terms in 5D. We perform the analysis in the context of the Berger-Kostelecky model (BK), adding one compactified dimension that explicitly breaks the Lorentz invariance. We introduce terms that encode this breaking, and find non trivial restrictions over boundary conditions of fields that one needs to close the supersymmetric algebra.
Lorentz transformation of blackbody radiation.
Ford, G W; O'Connell, R F
2013-10-01
We present a simple calculation of the Lorentz transformation of the spectral distribution of blackbody radiation at temperature T. Here we emphasize that T is the temperature in the blackbody rest frame and does not change. We thus avoid the confused and confusing question of how temperature transforms. We show by explicit calculation that at zero temperature the spectral distribution is invariant. At finite temperature we find the well-known result familiar in discussions of the 2.7 K cosmic radiation.
Transforming to Lorentz gauge on de Sitter
Miao, S. P.; Tsamis, N. C.; Woodard, R. P.
2009-12-15
We demonstrate that certain gauge fixing functionals cannot be added to the action on backgrounds such as de Sitter, in which a linearization instability is present. We also construct the field-dependent gauge transformation that carries the electromagnetic vector potential from a convenient, non-de Sitter invariant gauge to the de Sitter invariant, Lorentz gauge. The transformed propagator agrees with the de Sitter invariant result previously found by solving the propagator equation in Lorentz gauge. This shows that the gauge transformation technique will eliminate unphysical breaking of de Sitter invariance introduced by a gauge condition. It is suggested that the same technique can be used to finally resolve the issue of whether or not free gravitons are de Sitter invariant.
Nonrelativisitic Ideal Gases and Lorentz Violations
NASA Astrophysics Data System (ADS)
Colladay, D.; McDonald, P.
2005-04-01
We develop statistical mechanics for a nonrelativisitic ideal gas in the presence of Lorentz violating background fields. The analysis is performed using the Standard-Model Extension (SME). We derive the corresponding laws of thermodynamics and find that, to lowest order in Lorentz violation, the scalar thermodynamic variables are corrected by a rotationally invariant combination of the Lorentz terms which can be interpreted in terms of a (frame dependent) effective mass. We find that spin couplings can induce a temperature independent polarization in the gas that is not present in the conventional case.
Canonical formalism of a Lorentz gauge theory of gravitation
Liu Yao-yang; Yuan Ka-jia; Zhang Yuan-zhong
1987-04-01
In this paper we choose a Lagrangian which is invariant under general coordinate transformations and local Lorentz transformations. The discussion is focused on the classical Lagrangian equations of motion and the canonical formalism corresponding to this Lagrangian.
Infrared Lorentz violation and slowly instantaneous electricity.
Dvali, Gia; Papucci, Michele; Schwartz, Matthew D
2005-05-20
We study a modification of electromagnetism which violates Lorentz invariance at large distances. In this theory, electromagnetic waves are massive, but the static force between charged particles is Coulomb, not Yukawa. At very short distances the theory looks just like QED. But for distances larger than 1/m the massive dispersion relation of the waves can be appreciated, and the Coulomb force can be used to communicate faster than the speed of light. In fact, electrical signals are transmitted instantly, but take a time approximately 1/m to build up to full strength. After that, undamped oscillations of the electric field are set in and continue until they are dispersed by the arrival of the Lorentz-obeying part of the transmission. Experimental constraints imply that the Compton wavelength of the photon may be as small as 6000 km. This bound is weaker than for a Lorentz-invariant mass, essentially because the Coulomb constraint is removed.
Low Energy Lorentz Violation from Modified Dispersion at High Energies.
Husain, Viqar; Louko, Jorma
2016-02-12
Many quantum theories of gravity propose Lorentz-violating dispersion relations of the form ω=|k|f(|k|/M⋆), with recovery of approximate Lorentz invariance at energy scales much below M⋆. We show that a quantum field with this dispersion predicts drastic low energy Lorentz violation in atoms modeled as Unruh-DeWitt detectors, for any f that dips below unity somewhere. As an example, we show that polymer quantization motivated by loop quantum gravity predicts such Lorentz violation below current ion collider rapidities.
Maxwell Duality, Lorentz Invariance, and Topological Phase
NASA Technical Reports Server (NTRS)
Dowling, J.; Williams, C.; Franson, J.
1999-01-01
We discuss the Maxwell electromagnetic duality relations between the Aharonov-Bohm, Aharonov-Casher, and He-McKellar-Wilkens topological phases, which allows a unified description of all three phenomena.
Constraining Lorentz violation with cosmology.
Zuntz, J A; Ferreira, P G; Zlosnik, T G
2008-12-31
The Einstein-aether theory provides a simple, dynamical mechanism for breaking Lorentz invariance. It does so within a generally covariant context and may emerge from quantum effects in more fundamental theories. The theory leads to a preferred frame and can have distinct experimental signatures. In this Letter, we perform a comprehensive study of the cosmological effects of the Einstein-aether theory and use observational data to constrain it. Allied to previously determined consistency and experimental constraints, we find that an Einstein-aether universe can fit experimental data over a wide range of its parameter space, but requires a specific rescaling of the other cosmological densities.
Renormalization of Lorentz violating theories
Anselmi, Damiano; Halat, Milenko
2007-12-15
We classify the unitary, renormalizable, Lorentz violating quantum field theories of interacting scalars and fermions, obtained improving the behavior of Feynman diagrams by means of higher space derivatives. Higher time derivatives are not generated by renormalization. Renormalizability is ensured by a ''weighted power-counting'' criterion. The theories contain a dimensionful parameter {lambda}{sub L}, yet a set of models are classically invariant under a weighted scale transformation, which is anomalous at the quantum level. Formulas for the weighted trace anomaly are derived. The renormalization-group properties are studied.
Test of Lorentz symmetry with trapped ions
NASA Astrophysics Data System (ADS)
Pruttivarasin, Thaned
2016-05-01
The outcome of an experiment should not depend on the orientation of the apparatus in space. This important cornerstone of physics is deeply engrained into the Standard Model of Physics by requiring that all fields must be Lorentz invariant. However, it is well-known that the Standard Model is incomplete. Some theories conjecture that at the Planck scale Lorentz symmetry might be broken and measurable at experimentally accessible energy scales. Therefore, a search for violation of Lorentz symmetry directly probes physics beyond the Standard model. We present a novel experiment utilizing trapped calcium ions as a direct probe of Lorentz-violation in the electron-photon sector. We monitor the energy between atomic states with different orientations of the electronic wave-functions as they rotate together with the motion of the Earth. This is analogous to the famous Michelson-Morley experiment. To remove magnetic field noise, we perform the experiment with the ions prepared in the decoherence-free states. Our result improves on the most stringent bounds on Lorentz symmetry for electrons by 100 times. The experimental scheme is readily applicable to many ion species, hence opening up paths toward much improved test of Lorentz symmetry in the future. (Ph. D. Advisor: Hartmut Haeffner, University of California, Berkeley).
Lorentz covariance of loop quantum gravity
NASA Astrophysics Data System (ADS)
Rovelli, Carlo; Speziale, Simone
2011-05-01
The kinematics of loop gravity can be given a manifestly Lorentz-covariant formulation: the conventional SU(2)-spin-network Hilbert space can be mapped to a space K of SL(2,C) functions, where Lorentz covariance is manifest. K can be described in terms of a certain subset of the projected spin networks studied by Livine, Alexandrov and Dupuis. It is formed by SL(2,C) functions completely determined by their restriction on SU(2). These are square-integrable in the SU(2) scalar product, but not in the SL(2,C) one. Thus, SU(2)-spin-network states can be represented by Lorentz-covariant SL(2,C) functions, as two-component photons can be described in the Lorentz-covariant Gupta-Bleuler formalism. As shown by Wolfgang Wieland in a related paper, this manifestly Lorentz-covariant formulation can also be directly obtained from canonical quantization. We show that the spinfoam dynamics of loop quantum gravity is locally SL(2,C)-invariant in the bulk, and yields states that are precisely in K on the boundary. This clarifies how the SL(2,C) spinfoam formalism yields an SU(2) theory on the boundary. These structures define a tidy Lorentz-covariant formalism for loop gravity.
Theoretical Studies of Lorentz and CPT Symmetry
NASA Technical Reports Server (NTRS)
Kostelecky, V. Alan
2005-01-01
The fundamental symmetries studied here are Lorentz and CPT invariance, which form a cornerstone of the relativistic quantum theories used in modern descriptions of nature. The results obtained during the reporting period focus on the idea, originally suggested by the P.I. and his group in the late 1980s, that observable CPT and Lorentz violation in nature might emerge from the qualitatively new physics expected to hold at the Planck scale. What follows is a summary of results obtained during the period of this grant.
The 1895 Lorentz transformations: historical issues and present teaching
NASA Astrophysics Data System (ADS)
Provost, Jean-Pierre; Bracco, Christian
2016-07-01
We present the pedagogical interest for the teaching of special relativity of the 1895 Lorentz transformations, which are a simple modification of the Galilean ones, satisfying the invariance of light velocity at first order in V/c. Since they are also the infinitesimal version of the better known but more complicated 1904 Lorentz ones, they allow us to address the main topics of this teaching (time dilatation, length contraction, relativistic dynamics, invariance of electromagnetism) and to recover standard results through simple integrations or the use of invariants. In addition, they are directly related to important historical issues, including Einstein’s 1911 relativistic approach to gravitation.
Cavity tests of parity-odd Lorentz violations in electrodynamics
NASA Astrophysics Data System (ADS)
Mewes, Matthew; Petroff, Alexander
2007-03-01
Electromagnetic resonant cavities form the basis for a number modern tests of Lorentz invariance. The geometry of most of these experiments implies unsuppressed sensitivities to parity-even Lorentz violations only. Parity-odd violations typically enter through suppressed boost effects, causing a reduction in sensitivity by roughly 4 orders of magnitude. Here we discuss possible techniques for achieving unsuppressed sensitivities to parity-odd violations using asymmetric resonators.
Limits on Lorentz violation from forbidden β decays.
Noordmans, J P; Wilschut, H W; Timmermans, R G E
2013-10-25
Forbidden (slow) β decays offer new opportunities to test the invariance of the weak interaction under Lorentz transformations. Within a general effective field theory framework we analyze and reinterpret the only two relevant experiments, performed in the 1970s, dedicated to search for a preferred direction in space in first- and second-forbidden β decays. We show that the results of these experiments put strong and unique limits on Lorentz violation, and in particular on the presence of several interactions in the modern Lorentz-violating standard model extension. We discuss prospects to improve on these limits.
Combined Search for Lorentz Violation in Short-Range Gravity
NASA Astrophysics Data System (ADS)
Shao, Cheng-Gang; Tan, Yu-Jie; Tan, Wen-Hai; Yang, Shan-Qing; Luo, Jun; Tobar, Michael Edmund; Bailey, Quentin G.; Long, J. C.; Weisman, E.; Xu, Rui; Kostelecký, V. Alan
2016-08-01
Short-range experiments testing the gravitational inverse-square law at the submillimeter scale offer uniquely sensitive probes of Lorentz invariance. A combined analysis of results from the short-range gravity experiments HUST-2015, HUST-2011, IU-2012, and IU-2002 permits the first independent measurements of the 14 nonrelativistic coefficients for Lorentz violation in the pure-gravity sector at the level of 10-9 m2 , improving by an order of magnitude the sensitivity to numerous types of Lorentz violation involving quadratic curvature derivatives and curvature couplings.
Combined Search for Lorentz Violation in Short-Range Gravity.
Shao, Cheng-Gang; Tan, Yu-Jie; Tan, Wen-Hai; Yang, Shan-Qing; Luo, Jun; Tobar, Michael Edmund; Bailey, Quentin G; Long, J C; Weisman, E; Xu, Rui; Kostelecký, V Alan
2016-08-12
Short-range experiments testing the gravitational inverse-square law at the submillimeter scale offer uniquely sensitive probes of Lorentz invariance. A combined analysis of results from the short-range gravity experiments HUST-2015, HUST-2011, IU-2012, and IU-2002 permits the first independent measurements of the 14 nonrelativistic coefficients for Lorentz violation in the pure-gravity sector at the level of 10^{-9} m^{2}, improving by an order of magnitude the sensitivity to numerous types of Lorentz violation involving quadratic curvature derivatives and curvature couplings.
Neutrino beam constraints on flavor-diagonal Lorentz violation
NASA Astrophysics Data System (ADS)
Altschul, Brett
2013-05-01
Breaking of isotropy and Lorentz boost invariance in the dynamics of second-generation leptons would lead to direction-dependent changes in the lifetimes of charged pions. This would make the intensity of a neutrino beam produced via pion decay a function of the beam orientation. The experimental signature of this phenomenon—sidereal variations in the event rate at a downstream neutrino detector—has already been studied, in searches for Lorentz-violating neutrino oscillations. Existing analyses of MINOS near detector data can be used to constrain the flavor-diagonal Lorentz violation coefficients affecting muon neutrino speeds at roughly the 10-5 level.
NASA Astrophysics Data System (ADS)
Heras, Ricardo
2017-01-01
In this paper I briefly discuss and compare four easy derivations of the Lorentz transformations. Two of these derivations assume the invariance of the Minkowski spacetime interval in inertial frames and the other two assume the invariance of the d’Alembert operator in these frames. These derivations are suitable for a first view of special relativity. Finally, I discuss the comment made by Di Rocco on my original paper, ‘Lorentz transformations and the wave equation’ (2016 Eur. J. Phys. 37 025603).
Bounds on Lorentz and CPT violation from the Earth-ionosphere cavity
Mewes, Matthew
2008-11-01
Electromagnetic resonant cavities form the basis of many tests of Lorentz invariance involving photons. The effects of some forms of Lorentz violation scale with cavity size. We investigate possible signals of violations in the naturally occurring resonances formed in the Earth-ionosphere cavity. Comparison with observed resonances places the first terrestrial constraints on coefficients associated with dimension-three Lorentz-violating operators at the level of 10{sup -20} GeV.
Lorentz-violating gravitoelectromagnetism
Bailey, Quentin G.
2010-09-15
The well-known analogy between a special limit of general relativity and electromagnetism is explored in the context of the Lorentz-violating standard-model extension. An analogy is developed for the minimal standard-model extension that connects a limit of the CPT-even component of the electromagnetic sector to the gravitational sector. We show that components of the post-Newtonian metric can be directly obtained from solutions to the electromagnetic sector. The method is illustrated with specific examples including static and rotating sources. Some unconventional effects that arise for Lorentz-violating electrostatics and magnetostatics have an analog in Lorentz-violating post-Newtonian gravity. In particular, we show that even for static sources, gravitomagnetic fields arise in the presence of Lorentz violation.
Modified Lorentz transformations in deformed special relativity
NASA Astrophysics Data System (ADS)
Salesi, G.; Greselin, M.; Deleidi, L.; Peruzza, R. A.
2017-05-01
We have extended a recent approach to Deformed Special Relativity based on deformed dispersion laws, entailing modified Lorentz transformations and, at the same time, noncommutative geometry and intrinsically discrete space-time. In so doing we have obtained the explicit form of the modified Lorentz transformations for a special class of modified momentum-energy relations often found in literature and arising from quantum gravity and elementary particle physics. Actually, our theory looks as a very simple and natural extension of special relativity to include a momentum cutoff at the Planck scale. In particular, the new Lorentz transformations do imply that for high boost speed (V ˜ c) the deformed Lorentz factor does not diverge as in ordinary relativity, but results to be upper bounded by a large finite value of the order of the ratio between the Planck mass and the particle mass. We have also predicted that a generic boost leaves unchanged Planck energy and momentum, which result invariant with respect to any reference frame. Finally, through matrix deformation functions, we have extended our theory to more general cases with dispersion laws containing momentum-energy mixed terms.
Reparametrization invariant collinear operators
Marcantonini, Claudio; Stewart, Iain W.
2009-03-15
In constructing collinear operators, which describe the production of energetic jets or energetic hadrons, important constraints are provided by reparametrization invariance (RPI). RPI encodes Lorentz invariance in a power expansion about a collinear direction, and connects the Wilson coefficients of operators at different orders in this expansion to all orders in {alpha}{sub s}. We construct reparametrization invariant collinear objects. The expansion of operators built from these objects provides an efficient way of deriving RPI relations and finding a minimal basis of operators, particularly when one has an observable with multiple collinear directions and/or soft particles. Complete basis of operators is constructed for pure glue currents at twist-4, and for operators with multiple collinear directions, including those appearing in e{sup +}e{sup -}{yields}3 jets, and for pp{yields}2 jets initiated via gluon fusion.
Planar factors of proper homogeneous Lorentz transformations
Fahnline, D.E.
1985-02-01
This article discusses two constructions factoring proper homogeneous Lorentz transformations H into the product of two planar transformations. A planar transformation is a proper homogeneous Lorentz transformation changing vectors in a two-flat through the origin, called the transformation two-flat, into new vectors in the same two-flat and which leaves unchanged vectors in the orthogonal two-flat, called the pointwise invariant two-flat. The first construction provides two planar factors such that a given timelike vector lies in the transformation two-flat of one and in the pointwise invariant two-flat of the other; it leads to several basic conditions on the trace of H and to necessary and sufficient conditions for H to be planar. The second construction yields explicit formulas for the orthogonal factors of H when they exist and are unique, where two planar transformations are orthogonal if the transformation two-flat of one is the pointwise invariant two-flat of the other.
Lorentz violating p-form gauge theories in superspace
NASA Astrophysics Data System (ADS)
Upadhyay, Sudhaker; Shah, Mushtaq B.; Ganai, Prince A.
2017-03-01
Very special relativity (VSR) keeps the main features of special relativity but breaks rotational invariance due to an intrinsic preferred direction. We study the VSR-modified extended BRST and anti-BRST symmetry of the Batalin-Vilkovisky (BV) actions corresponding to the p=1,2,3-form gauge theories. Within the VSR framework, we discuss the extended BRST invariant and extended BRST and anti-BRST invariant superspace formulations for these BV actions. Here we observe that the VSR-modified extended BRST invariant BV actions corresponding to the p=1,2,3-form gauge theories can be written in a manifestly covariant manner in a superspace with one Grassmann coordinate. Moreover, two Grassmann coordinates are required to describe the VSR-modified extended BRST and extended anti-BRST invariant BV actions in a superspace. These results are consistent with the Lorentz-invariant (special relativity) formulation.
Extending the Lorentz transformation by characteristic coordinates
NASA Technical Reports Server (NTRS)
Jones, R. T.
1976-01-01
The problem considered is that of rectilinear motion with variable velocity. The paper gives, by an elementary construction, a system of coordinates which is conformal in a restricted region near the axis of the motion. In such coordinates the velocity of light remains invariant even for observers moving with variable velocity. By a particular choice of the scale relation the restricted conformal transformations can be made to reduce to the Lorentz transformation everywhere in the case of constant velocity and locally in the case of variable velocity.
Lorentz violations in multifractal spacetimes
NASA Astrophysics Data System (ADS)
Calcagni, Gianluca
2017-05-01
Using the recent observation of gravitational waves (GW) produced by a black-hole merger, we place a lower bound on the energy above which a multifractal spacetime would display an anomalous geometry and, in particular, violations of Lorentz invariance. In the so-called multifractional theory with q-derivatives, we show that the deformation of dispersion relations is much stronger than in generic quantum-gravity approaches (including loop quantum gravity) and, contrary to the latter, present observations on GWs can place very strong bounds on the characteristic scales at which spacetime deviates from standard Minkowski. The energy at which multifractal effects should become apparent is E_{*}>10^{14} {GeV} (thus improving previous bounds by 12 orders of magnitude) when the exponents in the measure are fixed to their central value 1 / 2. We also estimate, for the first time, the effect of logarithmic oscillations in the measure (corresponding to a discrete spacetime structure) and find that they do not change much the bounds obtained in their absence, unless the amplitude of the oscillations is fine tuned. This feature, unavailable in known quantum-gravity scenarios, may help the theory to avoid being ruled out by gamma-ray burst (GRB) observations, for which E_{*}> 10^{17} {GeV} or greater.
Cosmological constraints on Lorentz violating dark energy
Audren, B.; Lesgourgues, J.; Sibiryakov, S. E-mail: Diego.Blas@cern.ch E-mail: Sergey.Sibiryakov@cern.ch
2013-08-01
The role of Lorentz invariance as a fundamental symmetry of nature has been lately reconsidered in different approaches to quantum gravity. It is thus natural to study whether other puzzles of physics may be solved within these proposals. This may be the case for the cosmological constant problem. Indeed, it has been shown that breaking Lorentz invariance provides Lagrangians that can drive the current acceleration of the universe without experiencing large corrections from ultraviolet physics. In this work, we focus on the simplest model of this type, called ΘCDM, and study its cosmological implications in detail. At the background level, this model cannot be distinguished from ΛCDM. The differences appear at the level of perturbations. We show that in ΘCDM, the spectrum of CMB anisotropies and matter fluctuations may be affected by a rescaling of the gravitational constant in the Poisson equation, by the presence of extra contributions to the anisotropic stress, and finally by the existence of extra clustering degrees of freedom. To explore these modifications accurately, we modify the Boltzmann code class. We then use the parameter inference code Monte Python to confront ΘCDM with data from WMAP-7, SPT and WiggleZ. We obtain strong bounds on the parameters accounting for deviations from ΛCDM. In particular, we find that the discrepancy between the gravitational constants appearing in the Poisson and Friedmann equations is constrained at the level of 1.8%.
NASA Astrophysics Data System (ADS)
Ebner, Dieter W.
1991-11-01
A Lorentz-invariant model of vacuum is given in the form of a 7-dimensional manifold endowed with a statistical metrical tensor. Certain scalar fields on this manifold behave then as spinor fields when viewed from their space-time projection. This paper generalizes previous work fromSO(3)-covariance to Lorentz-covariance.
Lorentz force particle analyzer
NASA Astrophysics Data System (ADS)
Wang, Xiaodong; Thess, André; Moreau, René; Tan, Yanqing; Dai, Shangjun; Tao, Zhen; Yang, Wenzhi; Wang, Bo
2016-07-01
A new contactless technique is presented for the detection of micron-sized insulating particles in the flow of an electrically conducting fluid. A transverse magnetic field brakes this flow and tends to become entrained in the flow direction by a Lorentz force, whose reaction force on the magnetic-field-generating system can be measured. The presence of insulating particles suspended in the fluid produce changes in this Lorentz force, generating pulses in it; these pulses enable the particles to be counted and sized. A two-dimensional numerical model that employs a moving mesh method demonstrates the measurement principle when such a particle is present. Two prototypes and a three-dimensional numerical model are used to demonstrate the feasibility of a Lorentz force particle analyzer (LFPA). The findings of this study conclude that such an LFPA, which offers contactless and on-line quantitative measurements, can be applied to an extensive range of applications. These applications include measurements of the cleanliness of high-temperature and aggressive molten metal, such as aluminum and steel alloys, and the clean manufacturing of semiconductors.
Bernardini, A. E.; Rocha, R. da
2007-03-15
We work on some general extensions of the formalism for theories which preserve the relativity of inertial frames with a nonlinear action of the Lorentz transformations on momentum space. Relativistic particle models invariant under the corresponding deformed symmetries are presented with particular emphasis on deformed dilatation transformations. The algebraic transformations relating the deformed symmetries with the usual (undeformed) ones are provided in order to preserve the Lorentz algebra. Two distinct cases are considered: a deformed dilatation transformation with a spacelike preferred direction and a very special relativity embedding with a lightlike preferred direction. In both analysis we consider the possibility of introducing quantum deformations of the corresponding symmetries such that the spacetime coordinates can be reconstructed and the particular form of the real space-momentum commutator remains covariant. Eventually feasible experiments, for which the nonlinear Lorentz dilatation effects here pointed out may be detectable, are suggested.
Impossibility of superluminal travel in Lorentz violating theories
NASA Astrophysics Data System (ADS)
Coutant, Antonin; Finazzi, Stefano; Liberati, Stefano; Parentani, Renaud
2012-03-01
Warp drives are space-times allowing for superluminal travel. However, they are quantum mechanically unstable because they produce a Hawking-like radiation which is blue shifted at their front wall without any bound. We reexamine this instability when local Lorentz invariance is violated at ultrahigh energy by dispersion, as in some theories of quantum gravity. Interestingly, even though the ultraviolet divergence is now regulated, warp drives are still unstable. Moreover the type of instability is different whether one uses a subluminal or a superluminal dispersion relation. In the first case, a black-hole laser yields an exponential amplification of the emitted flux whereas, in the second, infrared effects produce a linear growth of that flux. These results suggest that chronology could still be protected when violating Lorentz invariance.
New parametrization of lorentz transformations and tachyonic motion in special theory of relativity
Kapuscik, E.
2011-06-15
Assuming the existence of an invariant velocity a slightly generalized form of Lorentz transformations is derived. The group of these transformations has a simpler composition law than the group of standard Lorentz transformations has. It is shown that this new form allows the description of both subluminal and superluminal motions. It also allows to find all velocity-dependent tensors. In particular, the tachyonic momentum as a function of superluminal velocity is derived.
Strongly enhanced effects of Lorentz symmetry violation in entangled Yb+ ions
NASA Astrophysics Data System (ADS)
Dzuba, V. A.; Flambaum, V. V.; Safronova, M. S.; Porsev, S. G.; Pruttivarasin, T.; Hohensee, M. A.; Häffner, H.
2016-05-01
A number of theories aiming at unifying gravity with other fundamental interactions, including field theory, suggest the violation of Lorentz symmetry. Whereas the energy scale of such strongly Lorentz-symmetry-violating physics is much higher than that attainable at present by particle accelerators, Lorentz violation may nevertheless be detectable via precision measurements at low energies. Here, we carry out a systematic theoretical investigation to identify which atom shows the greatest promise for detecting a Lorentz symmetry violation in the electron-photon sector. We found that the ytterbium ion (Yb+) is an ideal system with high sensitivity, as well as excellent experimental controllability. By applying quantum-information-inspired technology to Yb+, we expect tests of local Lorentz invariance (LLI) violating physics in the electron-photon sector to reach levels of 10-23--five orders of magnitude more sensitive than the current best bounds.
The role of singular spinor fields in a torsional gravity, Lorentz-violating, framework
NASA Astrophysics Data System (ADS)
Ferrari, A. F.; Neto, J. A. S.; da Rocha, R.
2017-05-01
In this work, we consider a generalization of quantum electrodynamics including Lorentz violation and torsional-gravity, in the context of general spinor fields as classified in the Lounesto scheme. Singular spinor fields will be shown to be less sensitive to the Lorentz violation, as far as couplings between the spinor bilinear covariants and torsion are regarded. In addition, we prove that flagpole spinor fields do not admit minimal coupling to the torsion. In general, mass dimension four couplings are deeply affected when singular—flagpoles—spinors are considered, instead of the usual Dirac spinors. We also construct a mapping between spinors in the covariant framework and spinors in Lorentz symmetry breaking scenarios, showing how one may transliterate spinors of different classes between the two cases. Specific examples concerning the mapping of Dirac spinor fields in Lorentz violating scenarios into flagpole and flag-dipole spinors with full Lorentz invariance (including the cases of Weyl and Majorana spinors) are worked out.
Lorentz symmetry breaking in a cosmological context
NASA Astrophysics Data System (ADS)
Gresham, Moira I.
This thesis is comprised primarily of work from three independent papers, written in collaboration with Sean Carroll, Tim Dulaney, and Heywood Tam. The original motivation for the projects undertaken came from revisiting the standard assumption of spatial isotropy during inflation. Each project relates to the spontaneous breaking of Lorentz symmetry---in early Universe cosmology or in the context of effective field theory, in general. Chapter 1 is an introductory chapter that provides context for the thesis. Chapter 2 is an investigation of the stability of theories in which Lorentz invariance is spontaneously broken by fixed-norm vector "aether" fields. It is shown that models with generic kinetic terms are plagued either by ghosts or by tachyons, and are therefore physically unacceptable. Chapter 3 is an investigation of the phenomenological properties of the one low-energy effective theory of spontaneous Lorentz symmetry breaking found in the previous chapter to have a globally bounded Hamiltonian and a perturbatively stable vacuum---the theory in which the Lagrangian takes the form of a sigma model. In chapter 4 cosmological perturbations in a dynamical theory of inflation in which an Abelian gauge field couples directly to the inflaton are examined. The dominant effects of a small, persistent anisotropy on the primordial gravitational wave and curvature perturbation power spectra are found using the "in-in" formalism of perturbation theory. It is found that the primordial power spectra of cosmological perturbations gain significant direction dependence and that the fractional direction dependence of the tensor power spectrum is suppressed in comparison to that of the scalar power spectrum.
Standard model with partial gauge invariance
NASA Astrophysics Data System (ADS)
Chkareuli, J. L.; Kepuladze, Z.
2012-03-01
We argue that an exact gauge invariance may disable some generic features of the Standard Model which could otherwise manifest themselves at high energies. One of them might be related to the spontaneous Lorentz invariance violation (SLIV), which could provide an alternative dynamical approach to QED and Yang-Mills theories with photon and non-Abelian gauge fields appearing as massless Nambu-Goldstone bosons. To see some key features of the new physics expected we propose partial rather than exact gauge invariance in an extended SM framework. This principle applied, in some minimal form, to the weak hypercharge gauge field B μ and its interactions, leads to SLIV with B field components appearing as the massless Nambu-Goldstone modes, and provides a number of distinctive Lorentz breaking effects. Being naturally suppressed at low energies they may become detectable in high energy physics and astrophysics. Some of the most interesting SLIV processes are considered in significant detail.
NASA Astrophysics Data System (ADS)
Bedoya Fierro, D.; Kelkar, N. G.; Nowakowski, M.
2015-09-01
The proton charge and magnetization density distributions can be related to the well known Sachs electromagnetic form factors G E, M ( q 2) through Fourier transforms, only in the Breit frame. The Breit frame however moves with relativistic velocities in the Lab and a Lorentz boost must be applied before extracting the static properties of the proton from the corresponding densities. Apart from this, the Fourier transform relating the densities and form factors is inherently a non-relativistic expression. We show that the relativistic corrections to it can be obtained by extending the standard Breit equation to higher orders in its 1 /c 2 expansion. We find that the inclusion of the above corrections reduces the size of the proton as determined from electron proton scattering data by about 4%.
Scale invariance vs conformal invariance
NASA Astrophysics Data System (ADS)
Nakayama, Yu
2015-03-01
In this review article, we discuss the distinction and possible equivalence between scale invariance and conformal invariance in relativistic quantum field theories. Under some technical assumptions, we can prove that scale invariant quantum field theories in d = 2 space-time dimensions necessarily possess the enhanced conformal symmetry. The use of the conformal symmetry is well appreciated in the literature, but the fact that all the scale invariant phenomena in d = 2 space-time dimensions enjoy the conformal property relies on the deep structure of the renormalization group. The outstanding question is whether this feature is specific to d = 2 space-time dimensions or it holds in higher dimensions, too. As of January 2014, our consensus is that there is no known example of scale invariant but non-conformal field theories in d = 4 space-time dimensions under the assumptions of (1) unitarity, (2) Poincaré invariance (causality), (3) discrete spectrum in scaling dimensions, (4) existence of scale current and (5) unbroken scale invariance in the vacuum. We have a perturbative proof of the enhancement of conformal invariance from scale invariance based on the higher dimensional analogue of Zamolodchikov's c-theorem, but the non-perturbative proof is yet to come. As a reference we have tried to collect as many interesting examples of scale invariance in relativistic quantum field theories as possible in this article. We give a complementary holographic argument based on the energy-condition of the gravitational system and the space-time diffeomorphism in order to support the claim of the symmetry enhancement. We believe that the possible enhancement of conformal invariance from scale invariance reveals the sublime nature of the renormalization group and space-time with holography. This review is based on a lecture note on scale invariance vs conformal invariance, on which the author gave lectures at Taiwan Central University for the 5th Taiwan School on Strings and
Lorentz Violation and Matter-Antimatter asymmetry
NASA Astrophysics Data System (ADS)
Alfaro, Jorge; González, Pablo
2011-09-01
Recently many studies have considered the possibility of a Lorentz Invariance Violation (LIV), and explored its consequences in a wide range of experiments. If this is true, a LIV could explains some mysteries in Cosmology. In this paper specifically, we will analyze the effects on The Primordial Baryogenesis because it is one of the more important and mysterious phenomena of the Big-Bang, that happened at very high energies, so we have a real chance to obtain an important effect. We will see that this effect could exist, depending directly on the temperature, that is very high at this time in the history of the Universe. So, it is possible to use this result as a test for a LIV and explore the possibility that the boson that started the baryogenesis explains, in part, the dark matter. We will obtain estimates about the beginning time of the baryogenesis and the boson mass too, that come directly from the LIV.
Cosmology of a Lorentz violating Galileon theory
Haghani, Zahra; Shahidi, Shahab; Harko, Tiberiu; Sepangi, Hamid Reza E-mail: t.harko@ucl.ac.uk E-mail: s.shahidi@du.ac.ir
2015-05-01
We modify the scalar Einstein-aether theory by breaking the Lorentz invariance of a gravitational theory coupled to a Galileon type scalar field. This is done by introducing a Lagrange multiplier term into the action, thus ensuring that the gradient of the scalar field is time-like, with unit norm. The theory can also be considered as an extension to the mimetic dark matter theory, by adding some derivative self interactions to the action, which keeps the equation of motion at most second order in time derivatives. The cosmological implications of the model are discussed in detail. In particular, for pressure-less baryonic matter, we show that the universe experiences a late time acceleration. The cosmological implications of a special coupling between the scalar field and the trace of the energy-momentum tensor are also explored.
Lorentz symmetry violation in the fermion number anomaly with the chiral overlap operator
NASA Astrophysics Data System (ADS)
Makino, Hiroki; Morikawa, Okuto
2016-12-01
Recently, Grabowska and Kaplan proposed a four-dimensional lattice formulation of chiral gauge theories on the basis of a chiral overlap operator. We compute the classical continuum limit of the fermion number anomaly in this formulation. Unexpectedly, we find that the continuum limit contains a term which is not Lorentz invariant. The term is, however, proportional to the gauge anomaly coefficient, and thus the fermion number anomaly in this lattice formulation automatically restores the Lorentz-invariant form when and only when the anomaly cancellation condition is met.
NASA Astrophysics Data System (ADS)
Sakharov, Alexander; Ellis, John; Harries, Nicholas; Meregaglia, Anselmo; Rubbia, André
2009-06-01
It has been suggested that the interactions of energetic particles with the foamy structure of space-time thought to be generated by quantum-gravitational (QG) effects might violate Lorentz invariance, so that they do not propagate at a universal speed of light. We consider the limits that may be set on a linear or quadratic violation of Lorentz invariance in the propagation of energetic neutrinos, v/c = [1 ± (E/MvQG1)] or [1 ± (E/MvQG2)2], using data from supernova explosions and the OPERA long-baseline neutrino experiment.
Electrodynamics with Lorentz-violating operators of arbitrary dimension
Kostelecky, V. Alan; Mewes, Matthew
2009-07-01
The behavior of photons in the presence of Lorentz and CPT violation is studied. Allowing for operators of arbitrary mass dimension, we classify all gauge-invariant Lorentz- and CPT-violating terms in the quadratic Lagrange density associated with the effective photon propagator. The covariant dispersion relation is obtained, and conditions for birefringence are discussed. We provide a complete characterization of the coefficients for Lorentz violation for all mass dimensions via a decomposition using spin-weighted spherical harmonics. The resulting nine independent sets of spherical coefficients control birefringence, dispersion, and anisotropy in the photon propagator. We discuss the restriction of the general theory to various special models, including among others the minimal standard-model extension, the isotropic limit, the case of vacuum propagation, the nonbirefringent limit, and the vacuum-orthogonal model. The transformation of the spherical coefficients for Lorentz violation between the laboratory frame and the standard Sun-centered frame is provided. We apply the results to various astrophysical observations and laboratory experiments. Astrophysical searches of relevance include studies of birefringence and of dispersion. We use polarimetric and dispersive data from gamma-ray bursts to set constraints on coefficients for Lorentz violation involving operators of dimensions four through nine, and we describe the mixing of polarizations induced by Lorentz and CPT violation in the cosmic-microwave background. Laboratory searches of interest include cavity experiments. We present the general theory for searches with cavities, derive the experiment-dependent factors for coefficients in the vacuum-orthogonal model, and predict the corresponding frequency shift for a circular-cylindrical cavity.
The de Broglie Relations: Lorentz Invariance and Photons.
1985-08-01
OFIESOL %.. ~~Ronald G. Newburgh(678132 ACE T DO FORM 1473,833 APR SOITION OP iJAN73 IS OSOLSTE. UNC L1~ ASSI [ED- SECURITY CLASSIF ICATION Of THIS PAGE P...2. Newburgh, R. G. (1981) Optics in four dimensions - 1980, M. A. Machado and L. M. Narducci, Eds.. AIP Conference Proceedings 65:131-137. 3. Landau...A. Machado and L. M. Narducci, Eds.,* AlP Conference Proceedings 65:131-137. 3. Landau, L. D., and Lifshitz, E. M. (1982) The Classical Theory of
Spontaneous Lorentz violation: the case of infrared QED
NASA Astrophysics Data System (ADS)
Balachandran, A. P.; Kürkçüoǧlu, S.; de Queiroz, A. R.; Vaidya, S.
2015-02-01
It is by now clear that the infrared sector of quantum electrodynamics (QED) has an intriguingly complex structure. Based on earlier pioneering work on this subject, two of us recently proposed a simple modification of QED by constructing a generalization of the charge group of QED to the "Sky" group incorporating the well-known spontaneous Lorentz violation due to infrared photons, but still compatible in particular with locality (Balachandran and Vaidya, Eur Phys J Plus 128:118, 2013). It was shown that the "Sky" group is generated by the algebra of angle-dependent charges and a study of its superselection sectors has revealed a manifest description of spontaneous breaking of the Lorentz symmetry. We further elaborate this approach here and investigate in some detail the properties of charged particles dressed by the infrared photons. We find that Lorentz violation due to soft photons may be manifestly codified in an angle-dependent fermion mass, modifying therefore the fermion dispersion relations. The fact that the masses of the charged particles are not Lorentz invariant affects their spin content, and time dilation formulas for decays should also get corrections.
The Lorentz extension as consequence of the family symmetry
Wang Haijun
2008-05-15
In this paper, we postulate an algebraic model to explain how the symmetry of three lepton species plays its role in the Lorentz extension. Inspired by the two-to-one mapping between the SL(2,C) group and the Lorentz group, we design a mapping between the SL(3,C) group, which displays the family symmetry, and a generalized Lorentz group. Following the conventional method, we apply the mapping results to the Dirac equation to discuss its transformation invariance, and it turns out that only when the vertex matrix {gamma}{sub {mu}} is extended to the combination c{sub 1}{gamma}{sub {mu}}+c{sub 2}{gamma}{sub 5}{gamma}{sub {mu}} can the Dirac-equation form be reserved. At the same time, we find that the Lorentz group has to be extended with an additional generator {gamma}{sub 5}. The generalized vertex matrix is helpful in understanding the axial-like form of weak interaction and the neutrino oscillations.
Implications of Lorentz symmetry violation on a 5D supersymmetric model
NASA Astrophysics Data System (ADS)
García-Aguilar, J. D.; Pérez-Lorenzana, A.
2017-04-01
Field models with n extra spatial dimensions have a larger SO(1, 3 + n) Lorentz symmetry which is broken down to the standard SO(1, 3) four-dimensional one by the compactification process. By considering Lorentz violating operators in a 5D supersymmetric Wess-Zumino model, which otherwise conserve the standard four-dimensional Poincaré invariance, we show that supersymmetry (SUSY) can be restored upon a simple deformation of the supersymmetric transformations. However, SUSY is not preserved in the effective 4D theory that arises after compactification when the 5D Lorentz violating operators do not preserve Z2 : y →-y bulk parity. Our mechanism unveils a possible connection among Lorentz violation and the Scherk-Schwarz mechanism. We also show that parity preserving models, on the other hand, do provide well defined supersymmetric KK models.
Charged Lifshitz black hole and probed Lorentz-violation fermions from holography
NASA Astrophysics Data System (ADS)
Luo, Cheng-Jian; Kuang, Xiao-Mei; Shu, Fu-Wen
2017-06-01
We analytically obtain a new charged Lifshitz solution by adding a non-relativistic Maxwell field in Hořava-Lifshitz gravity. The black hole exhibits an anisotropic scaling between space and time (Lifshitz scaling) in the UV limit, while in the IR limit, the Lorentz invariance is approximately recovered. We introduce the probed Lorentz-violation fermions into the background and holographically investigate the spectral properties of the dual fermionic operator. The Lorentz-violation of the fermions will enhance the peak and correspond larger fermi momentum, which compensates the non-relativistic bulk effect of the dynamical exponent (z). For a fixed z, when the Lorentz-violation of fermions increases to a critical value, the behavior of the low energy excitation goes from a non-Fermi liquid type to a Fermi liquid type, which implies a kind of phase transition.
Low-energy phenomenology of scalarless standard-model extensions with high-energy Lorentz violation
Anselmi, Damiano; Ciuffoli, Emilio
2011-03-01
We consider renormalizable standard model extensions that violate Lorentz symmetry at high energies, but preserve CPT, and do not contain elementary scalar fields. A Nambu-Jona-Lasinio mechanism gives masses to fermions and gauge bosons and generates composite Higgs fields at low energies. We study the effective potential at the leading order of the large-N{sub c} expansion, prove that there exists a broken phase, and study the phase space. In general, the minimum may break invariance under boosts, rotations, and CPT, but we give evidence that there exists a Lorentz invariant phase. We study the spectrum of composite bosons and the low-energy theory in the Lorentz phase. Our approach predicts relations among the parameters of the low-energy theory. We find that such relations are compatible with the experimental data within theoretical errors. We also study the mixing among generations, the emergence of the CKM matrix, and neutrino oscillations.
Vacuum Cherenkov radiation in quantum electrodynamics with high-energy Lorentz violation
Anselmi, Damiano; Taiuti, Martina
2011-03-01
We study phenomena predicted by a renormalizable, CPT invariant extension of the standard model that contains higher-dimensional operators and violates Lorentz symmetry explicitly at energies greater than some scale {Lambda}{sub L}. In particular, we consider the Cherenkov radiation in vacuo. In a rather general class of dispersion relations, there exists an energy threshold above which radiation is emitted. The threshold is enhanced in composite particles by a sort of kinematic screening mechanism. We study the energy loss and compare the predictions of our model with known experimental bounds on Lorentz violating parameters and observations of ultrahigh-energy cosmic rays. We argue that the scale of Lorentz violation {Lambda}{sub L} (with preserved CPT invariance) can be smaller than the Planck scale, actually as small as 10{sup 14}-10{sup 15} GeV. Our model also predicts the Cherenkov radiation of neutral particles.
Constaints on Lorentz symmetry violations using lunar laser ranging observations
NASA Astrophysics Data System (ADS)
Bourgoin, Adrien
2016-12-01
General Relativity (GR) and the standard model of particle physics provide a comprehensive description of the four interactions of nature. A quantum gravity theory is expected to merge these two pillars of modern physics. From unification theories, such a combination would lead to a breaking of fundamental symmetry appearing in both GR and the standard model of particle physics as the Lorentz symmetry. Lorentz symmetry violations in all fields of physics can be parametrized by an effective field theory framework called the standard-model extension (SME). Local Lorentz Invariance violations in the gravitational sector should impact the orbital motion of bodies inside the solar system, such as the Moon. Thus, the accurate lunar laser ranging (LLR) data can be analyzed in order to study precisely the lunar motion to look for irregularities. For this purpose, ELPN (Ephéméride Lunaire Parisienne Numérique), a new lunar ephemeris has been integrated in the SME framework. This new numerical solution of the lunar motion provides time series dated in temps dynamique barycentrique (TDB). Among that series, we mention the barycentric position and velocity of the Earth-Moon vector, the lunar libration angles, the time scale difference between the terrestrial time and TDB and partial derivatives integrated from variational equations. ELPN predictions have been used to analyzed LLR observations. In the GR framework, the residuals standard deviations has turned out to be the same order of magnitude compare to those of INPOP13b and DE430 ephemerides. In the framework of the minimal SME, LLR data analysis provided constraints on local Lorentz invariance violations. Spetial attention was paid to analyze uncertainties to provide the most realistic constraints. Therefore, in a first place, linear combinations of SME coefficients have been derived and fitted to LLR observations. In a second time, realistic uncertainties have been determined with a resampling method. LLR data
Conformal Lorentz geometry revisited
NASA Astrophysics Data System (ADS)
Teleman, Kostake
1996-02-01
The group U(2,2) and its subgroup SU(2,2) were considered by Penrose in his study of the conformal compactification M of the Minkowski space M [R. Penrose and W. Rindler, Spinors and Space-Time (Cambridge University, Cambridge, 1986) and R. O. Wells, Jr., Bull. Am. Math. Soc. I, 2 (1979)]. The standard representation of SU(2,2) in C4 and in M are the corner stones of twistor theory, which was created by Penrose to the double purpose of obtaining new solutions of Einstein equations and new insights on gravitational radiation. We think that other representations of SU(2,2) or U(2,2) could also bring some information in relativity [see also, Barut O. Asjim, in Noncompact Lie Groups and some of their Applications, edited by E. A. Tanner and R. Wilson (Kluwer Academic, Dordrecht, 1994), p. 103] and, accordingly, we propose an extension of Penrose twistor program. In this paper we deal with a new U(2,2)-space, which we denote by W. We show first that the SU(2,2)-space M introduced by Penrose is isomorphic to U(2), endowed with an action of SU(2,2) given by non-Abelian homographic transformations. These transformations keep invariant the equation det(u-v)=0, characterizing the pairs (u,v)∈U(2)×U(2) such that ``u lies on the light-cone of v.'' By definition, our space W consists of all pairs (u,v)∈U(2)×U(2) satisfying the condition det(u-v)≠0. The starting point of this article is the observation that W carries an SU(2,2)-invariant pseudo-Riemannian metric L:=Tr[(u-v)-1u˙ ×(u-v)-1v˙], of signature (4,4). (W,L) is in fact an irreducible symmetric space in Cartan's sense, which is isomorphic to the quotient SO(2,4)/S[O(1,1)×O(1,3)]. As an irreducible symmetric space, it is an 8-dimensional Einstein space, whose Ricci tensor is proportional to the metric tensor. We study the geodesic paths of this space giving the general solutions in terms of initial data and studying the constants of motion. In particular we determine the geodesic paths which exhibit two periods
Frank, Steven A
2016-01-01
In nematodes, environmental or physiological perturbations alter death's scaling of time. In human cancer, genetic perturbations alter death's curvature of time. Those changes in scale and curvature follow the constraining contours of death's invariant geometry. I show that the constraints arise from a fundamental extension to the theories of randomness, invariance and scale. A generalized Gompertz law follows. The constraints imposed by the invariant Gompertz geometry explain the tendency of perturbations to stretch or bend death's scaling of time. Variability in death rate arises from a combination of constraining universal laws and particular biological processes.
Frank, Steven A.
2016-01-01
In nematodes, environmental or physiological perturbations alter death’s scaling of time. In human cancer, genetic perturbations alter death’s curvature of time. Those changes in scale and curvature follow the constraining contours of death’s invariant geometry. I show that the constraints arise from a fundamental extension to the theories of randomness, invariance and scale. A generalized Gompertz law follows. The constraints imposed by the invariant Gompertz geometry explain the tendency of perturbations to stretch or bend death’s scaling of time. Variability in death rate arises from a combination of constraining universal laws and particular biological processes. PMID:27785361
Lorentz violation in supersymmetric field theories.
Nibbelink, Stefan Groot; Pospelov, Maxim
2005-03-04
We construct supersymmetric Lorentz violating operators for matter and gauge fields. We show that in the supersymmetric standard model the lowest possible dimension for such operators is five, and therefore they are suppressed by at least one power of an ultraviolet energy scale, providing a possible explanation for the smallness of Lorentz violation and its stability against radiative corrections. Supersymmetric Lorentz noninvariant operators do not lead to modifications of dispersion relations at high energies thereby escaping constraints from astrophysical searches for Lorentz violation.
The Need for a First-order Quasi Lorentz Transformation
Censor, D.
2010-11-25
Solving electromagnetic scattering problems involving non-uniformly moving objects or media requires an approximate but consistent extension of Einstein's Special Relativity theory, originally valid for constant velocities only. For moderately varying velocities a quasi Lorentz transformation is presented. The conditions for form-invariance of the Maxwell equations, the so-called ''principle of relativity'', are shown to hold for a broad class of motional modes and time scales. A simple example of scattering by a harmonically oscillating mirror is analyzed in detail. Application to generally orbiting objects is mentioned.
Cosmology of a universe with spontaneously broken Lorentz symmetry
Ferreira, P. G.; Gripaios, B. M.; Zlosnik, T. G.; Saffari, R.
2007-02-15
A self-consistent effective field theory of modified gravity has recently been proposed with spontaneous breaking of local Lorentz invariance. The symmetry is broken by a vector field with the wrong-sign mass term and it has been shown to have additional graviton modes and modified dispersion relations. In this paper we study the evolution of a homogeneous and isotropic universe in the presence of such a vector field with a minimum lying along the timelike direction. A plethora of different regimes is identified, such as accelerated expansion, loitering, collapse, and tracking.
Renormalization of high-energy Lorentz-violating QED
Anselmi, Damiano; Taiuti, Martina
2010-04-15
We study a QED extension that is unitary, CPT invariant, and super-renormalizable, but violates Lorentz symmetry at high energies, and contains higher-dimension operators (LVQED). Divergent diagrams are only one- and two-loop. We compute the one-loop renormalizations at high and low energies and analyze the relation between them. It emerges that the powerlike divergences of the low-energy theory are multiplied by arbitrary constants, inherited by the high-energy theory, and therefore can be set to zero at no cost, bypassing the hierarchy problem.
Probes of Lorentz violation in neutrino propagation
Ellis, John; Harries, Nicholas; Meregaglia, Anselmo; Sakharov, Alexander S.
2008-08-01
It has been suggested that the interactions of energetic particles with the foamy structure of space-time thought to be generated by quantum-gravitational (QG) effects might violate Lorentz invariance, so that they do not propagate at a universal speed of light. We consider the limits that may be set on a linear or quadratic violation of Lorentz invariance in the propagation of energetic neutrinos, v/c=[1{+-}(E/M{sub {nu}}{sub QG1})] or [1{+-}(E/M{sub {nu}}{sub QG2}){sup 2}], using data from supernova explosions and the OPERA long-baseline neutrino experiment. Using the SN1987a neutrino data from the Kamioka II, IMB, and Baksan experiments, we set the limits M{sub {nu}}{sub QG1}>2.7(2.5)x10{sup 10} GeV for subluminal (superluminal) propagation and M{sub {nu}}{sub QG2}>4.6(4.1)x10{sup 4} GeV at the 95% confidence level. A future galactic supernova at a distance of 10 kpc would have sensitivity to M{sub {nu}}{sub QG1}>2(4)x10{sup 11} GeV for subluminal (superluminal) propagation and M{sub {nu}}{sub QG2}>2(4)x10{sup 5} GeV. With the current CERN neutrinos to Gran Sasso extraction spill length of 10.5 {mu}s and with standard clock synchronization techniques, the sensitivity of the OPERA experiment would reach M{sub {nu}}{sub QG1}{approx}7x10{sup 5} GeV (M{sub {nu}}{sub QG2}{approx}8x10{sup 3} GeV) after 5 years of nominal running. If the time structure of the super proton synchrotron radio frequency bunches within the extracted CERN neutrinos to Gran Sasso spills could be exploited, these figures would be significantly improved to M{sub {nu}}{sub QG1}{approx}5x10{sup 7} GeV (M{sub {nu}}{sub QG2}{approx}4x10{sup 4} GeV). These results can be improved further if a similar time resolution can be achieved with neutrino events occurring in the rock upstream of the OPERA detector: we find potential sensitivities to M{sub {nu}}{sub QG1}{approx}4x10{sup 8} GeV and M{sub {nu}}{sub QG2}{approx}7x10{sup 5} GeV.
Probes of Lorentz violation in neutrino propagation
NASA Astrophysics Data System (ADS)
Ellis, John; Harries, Nicholas; Meregaglia, Anselmo; Rubbia, André; Sakharov, Alexander S.
2008-08-01
It has been suggested that the interactions of energetic particles with the foamy structure of space-time thought to be generated by quantum-gravitational (QG) effects might violate Lorentz invariance, so that they do not propagate at a universal speed of light. We consider the limits that may be set on a linear or quadratic violation of Lorentz invariance in the propagation of energetic neutrinos, v/c=[1±(E/MνQG1)] or [1±(E/MνQG2)2], using data from supernova explosions and the OPERA long-baseline neutrino experiment. Using the SN1987a neutrino data from the Kamioka II, IMB, and Baksan experiments, we set the limits MνQG1>2.7(2.5)×1010GeV for subluminal (superluminal) propagation and MνQG2>4.6(4.1)×104GeV at the 95% confidence level. A future galactic supernova at a distance of 10 kpc would have sensitivity to MνQG1>2(4)×1011GeV for subluminal (superluminal) propagation and MνQG2>2(4)×105GeV. With the current CERN neutrinos to Gran Sasso extraction spill length of 10.5μs and with standard clock synchronization techniques, the sensitivity of the OPERA experiment would reach MνQG1˜7×105GeV (MνQG2˜8×103GeV) after 5 years of nominal running. If the time structure of the super proton synchrotron radio frequency bunches within the extracted CERN neutrinos to Gran Sasso spills could be exploited, these figures would be significantly improved to MνQG1˜5×107GeV (MνQG2˜4×104GeV). These results can be improved further if a similar time resolution can be achieved with neutrino events occurring in the rock upstream of the OPERA detector: we find potential sensitivities to MνQG1˜4×108GeV and MνQG2˜7×105GeV.
Reflection theorem for Lorentz-Minkowski spaces
NASA Astrophysics Data System (ADS)
Lee, Nam-Hoon
2016-07-01
We generalize the reflection theorem of the Lorentz-Minkowski plane to that of the Lorentz-Minkowski spaces of higher dimensions. As a result, we show that an isometry of the Lorentz-Minkowski spacetime is a composition of at most 5 reflections.
Direct terrestrial test of Lorentz symmetry in electrodynamics to 10−18
Nagel, Moritz; Parker, Stephen R.; Kovalchuk, Evgeny V.; Stanwix, Paul L.; Hartnett, John G.; Ivanov, Eugene N.; Peters, Achim; Tobar, Michael E.
2015-01-01
Lorentz symmetry is a foundational property of modern physics, underlying the standard model of particles and general relativity. It is anticipated that these two theories are low-energy approximations of a single theory that is unified and consistent at the Planck scale. Many unifying proposals allow Lorentz symmetry to be broken, with observable effects appearing at Planck-suppressed levels; thus, precision tests of Lorentz invariance are needed to assess and guide theoretical efforts. Here we use ultrastable oscillator frequency sources to perform a modern Michelson–Morley experiment and make the most precise direct terrestrial test to date of Lorentz symmetry for the photon, constraining Lorentz violating orientation-dependent relative frequency changes Δν/ν to 9.2±10.7 × 10−19 (95% confidence interval). This order of magnitude improvement over previous Michelson–Morley experiments allows us to set comprehensive simultaneous bounds on nine boost and rotation anisotropies of the speed of light, finding no significant violations of Lorentz symmetry. PMID:26323989
Direct terrestrial test of Lorentz symmetry in electrodynamics to 10(-18).
Nagel, Moritz; Parker, Stephen R; Kovalchuk, Evgeny V; Stanwix, Paul L; Hartnett, John G; Ivanov, Eugene N; Peters, Achim; Tobar, Michael E
2015-09-01
Lorentz symmetry is a foundational property of modern physics, underlying the standard model of particles and general relativity. It is anticipated that these two theories are low-energy approximations of a single theory that is unified and consistent at the Planck scale. Many unifying proposals allow Lorentz symmetry to be broken, with observable effects appearing at Planck-suppressed levels; thus, precision tests of Lorentz invariance are needed to assess and guide theoretical efforts. Here we use ultrastable oscillator frequency sources to perform a modern Michelson-Morley experiment and make the most precise direct terrestrial test to date of Lorentz symmetry for the photon, constraining Lorentz violating orientation-dependent relative frequency changes Δν/ν to 9.2±10.7 × 10(-19) (95% confidence interval). This order of magnitude improvement over previous Michelson-Morley experiments allows us to set comprehensive simultaneous bounds on nine boost and rotation anisotropies of the speed of light, finding no significant violations of Lorentz symmetry.
Direct terrestrial test of Lorentz symmetry in electrodynamics to 10-18
NASA Astrophysics Data System (ADS)
Nagel, Moritz; Parker, Stephen R.; Kovalchuk, Evgeny V.; Stanwix, Paul L.; Hartnett, John G.; Ivanov, Eugene N.; Peters, Achim; Tobar, Michael E.
2015-09-01
Lorentz symmetry is a foundational property of modern physics, underlying the standard model of particles and general relativity. It is anticipated that these two theories are low-energy approximations of a single theory that is unified and consistent at the Planck scale. Many unifying proposals allow Lorentz symmetry to be broken, with observable effects appearing at Planck-suppressed levels; thus, precision tests of Lorentz invariance are needed to assess and guide theoretical efforts. Here we use ultrastable oscillator frequency sources to perform a modern Michelson-Morley experiment and make the most precise direct terrestrial test to date of Lorentz symmetry for the photon, constraining Lorentz violating orientation-dependent relative frequency changes Δν/ν to 9.2+/-10.7 × 10-19 (95% confidence interval). This order of magnitude improvement over previous Michelson-Morley experiments allows us to set comprehensive simultaneous bounds on nine boost and rotation anisotropies of the speed of light, finding no significant violations of Lorentz symmetry.
Small Lorentz violations in quantum gravity: do they lead to unacceptably large effects?
NASA Astrophysics Data System (ADS)
Gambini, Rodolfo; Rastgoo, Saeed; Pullin, Jorge
2011-08-01
We discuss the applicability of the argument of Collins, Pérez, Sudarsky, Urrutia and Vucetich to loop quantum gravity. This argument suggests that Lorentz violations, even ones that only manifest themselves at energies close to the Planck scale, have significant observational consequences at low energies when one considers perturbative quantum field theory and renormalization. We show that non-perturbative treatments like those of loop quantum gravity may generate deviations of Lorentz invariance of a different type than those considered by Collins et al (2004 Phys. Rev. Lett. 93 191301) that do not necessarily imply observational consequences at low energy.
NASA Astrophysics Data System (ADS)
Mondragon, Antonio R.
Observations from the 1930s until the present have established the existence of dark matter with an abundance that is much larger than that of luminous matter. Because none of the known particles of nature have the correct properties to be identified as the dark matter, various exotic candidates have been proposed. The neutralino of supersymmetric theories is the most promising example. Such cold dark matter candidates, however, lead to a conflict between the standard simulations of the evolution of cosmic structure and observations. Simulations predict excessive structure formation on small scales, including density cusps at the centers of galaxies, that is not observed. This conflict still persists in early 2007, and it has not yet been convincingly resolved by attempted explanations that invoke astrophysical phenomena, which would destroy or broaden all small scale structure. We have investigated another candidate that is perhaps more exotic: Lorentz-violating dark matter, which was originally motivated by an unconventional fundamental theory, but which in this dissertation is defined as matter which has a nonzero minimum velocity. Furthermore, the present investigation evolved into the broader goal of exploring the properties of Lorentz-violating matter and the astrophysical consequences-a subject which to our knowledge has not been previously studied. Our preliminary investigations indicated that this form of matter might have less tendency to form small-scale structure. These preliminary calculations certainly established that Lorentz-violating matter which always moves at an appreciable fraction of the speed of light will bind less strongly. However, the much more thorough set of studies reported here lead to the conclusion that, although the binding energy is reduced, the small-scale structure problem is not solved by Lorentz-violating dark matter. On the other hand, when we compare the predictions of Lorentz-violating dynamics with those of classical
2010-01-01
principle’s application to many common devices from jar wrenches to rock-climbing cams. 1 Introduction What principles should guide the design of...this paper we explore the possible role of the fingers in adapting to variations in object shape and pose. One common design approach is to adapt to...several fingers, the job of gracefully adapting to shape and pose variations may fall on the finger form. This work explores grasp invariance over shape and
Lorentz force optical coherence elastography
NASA Astrophysics Data System (ADS)
Wu, Chen; Singh, Manmohan; Han, Zhaolong; Raghunathan, Raksha; Liu, Chih-Hao; Li, Jiasong; Schill, Alexander; Larin, Kirill V.
2016-09-01
Quantifying tissue biomechanical properties can assist in detection of abnormalities and monitoring disease progression and/or response to a therapy. Optical coherence elastography (OCE) has emerged as a promising technique for noninvasively characterizing tissue biomechanical properties. Several mechanical loading techniques have been proposed to induce static or transient deformations in tissues, but each has its own areas of applications and limitations. This study demonstrates the combination of Lorentz force excitation and phase-sensitive OCE at ˜1.5 million A-lines per second to quantify the elasticity of tissue by directly imaging Lorentz force-induced elastic waves. This method of tissue excitation opens the possibility of a wide range of investigations using tissue biocurrents and conductivity for biomechanical analysis.
An Involution of Lorentz Transformations
NASA Astrophysics Data System (ADS)
Lubkin, Elihu
2000-04-01
Quadrilateral(axis, joystick) creates a proper Lorentz transformation dual to Quadrilateral(joystick, axis). The joystick is a line through axis and coaxis, selecting on them the intrinsic velocity and the intrinsic angle, respectively.(E. Lubkin, ``Reversed 3velocities'', APR99.) (Thing and co-thing are skew perpendicular with inverse nearest points.) This involution may be interesting: axis, coaxis, joystick, and cojoystick indeed do close in a quadrilateral. And this came up in multiplying coaxial Lorentz transformations A and B to get C. When result C is surprisingly not coaxial with A and B---this happens when A, B are improper of opposite types---the result is an (intrinsic) aboutface whose new axis is of old joystick form.
Possible cosmogenic neutrino constraints on Planck-scale Lorentz violation
Mattingly, David M.; Maccione, Luca; Galaverni, Matteo; Liberati, Stefano; Sigl, Günter E-mail: luca.maccione@desy.de E-mail: liberati@sissa.it
2010-02-01
We study, within an effective field theory framework, O(E{sup 2}M{sub Pl}{sup 2}) Planck-scale suppressed Lorentz invariance violation (LV) effects in the neutrino sector, whose size we parameterize by a dimensionless parameter η{sub ν}. We find deviations from predictions of Lorentz invariant physics in the cosmogenic neutrino spectrum. For positive O(1) coefficients no neutrino will survive above 10{sup 19}eV. The existence of this cutoff generates a bump in the neutrino spectrum at energies of 10{sup 17}eV. Although at present no constraint can be cast, as current experiments do not have enough sensitivity to detect ultra-high-energy neutrinos, we show that experiments in construction or being planned have the potential to cast limits as strong as η{sub ν}∼<10{sup −4} on the neutrino LV parameter, depending on how LV is distributed among neutrino mass states. Constraints on η{sub ν} < 0 can in principle be obtained with this strategy, but they require a more detailed modeling of how LV affects the neutrino sector.
Torsional Oscillations with Lorentz Force
ERIC Educational Resources Information Center
Gluck, Paul
2007-01-01
We have built a device that uses the Lorentz force on a current-carrying wire situated in a magnetic field, F = I L x B, in order to demonstrate a slowly varying alternating current by means of an optical lever. The apparatus consists of a horseshoe magnet, a length of thin enamel-coated wire (ours was 0.3 mm thick), a signal generator, a…
Torsional Oscillations with Lorentz Force
ERIC Educational Resources Information Center
Gluck, Paul
2007-01-01
We have built a device that uses the Lorentz force on a current-carrying wire situated in a magnetic field, F = I L x B, in order to demonstrate a slowly varying alternating current by means of an optical lever. The apparatus consists of a horseshoe magnet, a length of thin enamel-coated wire (ours was 0.3 mm thick), a signal generator, a…
An extension of the concept of inertial frame and of Lorentz transformation*
Kerner, Edward H.
1976-01-01
It is shown how particular kinds of fractional-linear (or projective) transformations generalize the notion of inertial frame in that they ensure that free-particle motion goes over into free-particle motion. A ten-parameter group of such transformations is produced which generalize Lorentz transformations, and which involve besides c (velocity of light) a new fundamental length b; they encompass the ordinary Lorentz group in the limit that b becomes infinite. These extended Lorentz transformations are most simply understood as a type of rotation in the space of homogeneous coordinates, a rotation that unifies 3-space rotations, frame-shifts to moving frames, and space- as well as time-translations. The structure of the invariant differential line element and of the wave operator that generalize those of special relativity are discussed, and implications for the possible revision of usual physical statements are pointed out. PMID:16592318
Battat, James B. R.; Chandler, John F.; Stubbs, Christopher W.
2007-12-14
We present constraints on violations of Lorentz invariance based on archival lunar laser-ranging (LLR) data. LLR measures the Earth-Moon separation by timing the round-trip travel of light between the two bodies and is currently accurate to the equivalent of a few centimeters (parts in 10{sup 11} of the total distance). By analyzing this LLR data under the standard-model extension (SME) framework, we derived six observational constraints on dimensionless SME parameters that describe potential Lorentz violation. We found no evidence for Lorentz violation at the 10{sup -6} to 10{sup -11} level in these parameters. This work constitutes the first LLR constraints on SME parameters.
Battat, James B R; Chandler, John F; Stubbs, Christopher W
2007-12-14
We present constraints on violations of Lorentz invariance based on archival lunar laser-ranging (LLR) data. LLR measures the Earth-Moon separation by timing the round-trip travel of light between the two bodies and is currently accurate to the equivalent of a few centimeters (parts in 10(11) of the total distance). By analyzing this LLR data under the standard-model extension (SME) framework, we derived six observational constraints on dimensionless SME parameters that describe potential Lorentz violation. We found no evidence for Lorentz violation at the 10(-6) to 10(-11) level in these parameters. This work constitutes the first LLR constraints on SME parameters.
Lifshitz scaling to Lorentz-violating high derivative operator and gamma-ray bursts
NASA Astrophysics Data System (ADS)
Passos, E.; Abreu, E. M. C.; Anacleto, M. A.; Brito, F. A.; Wotzasek, C.; Zarro, C. A. D.
2016-04-01
In this work, we use a Hořava-Lifshitz scaling to rewrite a Lorentz-violating higher-order derivative electrodynamics controlled by a background 4-vector nμ . The photon propagator is obtained, and we analyze the dispersion relation, and the observational results of gamma-ray burst (GRB) experiments are used. The limits of the critical exponent are discussed in light of the GRB data, and the physical implications are compared with the current GRB-Lorentz-invariance-violation literature. We show that the bound for the Lorentz-violating coupling for dimension-6 operators, obtained from a Hořava-Lifshitz scaling, is 8 orders of magnitude better than the result found without considering a Hořava-Lifshitz scaling and also that this bound is near to 1, which is expected to be relevant phenomenologically.
An extension of the concept of inertial frame and of Lorentz transformation.
Kerner, E H
1976-05-01
It is shown how particular kinds of fractional-linear (or projective) transformations generalize the notion of inertial frame in that they ensure that free-particle motion goes over into free-particle motion. A ten-parameter group of such transformations is produced which generalize Lorentz transformations, and which involve besides c (velocity of light) a new fundamental length b; they encompass the ordinary Lorentz group in the limit that b becomes infinite. These extended Lorentz transformations are most simply understood as a type of rotation in the space of homogeneous coordinates, a rotation that unifies 3-space rotations, frame-shifts to moving frames, and space- as well as time-translations. The structure of the invariant differential line element and of the wave operator that generalize those of special relativity are discussed, and implications for the possible revision of usual physical statements are pointed out.
Lorentz violation and Faddeev-Popov ghosts
Altschul, B.
2006-02-15
We consider how Lorentz-violating interactions in the Faddeev-Popov ghost sector will affect scalar QED. The behavior depends sensitively on whether the gauge symmetry is spontaneously broken. If the symmetry is not broken, Lorentz violations in the ghost sector are unphysical, but if there is spontaneous breaking, radiative corrections will induce Lorentz-violating and gauge-dependent terms in other sectors of the theory.
Implications of SU(2)_L x U(1) Symmetry for SIM(2) Invariant Neutrino Masses
Alan Dunn; Thomas Mehen
2006-10-16
We consider SU(2){sub L} x U(1) gauge invariant generalizations of a nonlocal, Lorentz violating mass term for neutrinos that preserves a SIM(2) subgroup. This induces Lorentz violating effects in QED as well as tree-level lepton family number violating interactions. Measurements of g{sub e} - 2 with trapped electrons severely constrain possible SIM(2) mass terms for electrons which violate C invariance. We study Lorentz violating effects in a C invariant and SIM(2) invariant extension of QED. We examine the Lorentz violating interactions of nonrelativistic electrons with electromagnetic fields to determine their impact on the spectroscopy of hydrogen-like atoms and g{sub e} - 2 measurements with trapped electrons. Generically, Lorentz violating corrections are suppressed by m{sub v}{sup 2}/m{sub e}{sup 2} and are within experimental limits. We study one-loop corrections to electron and photon self-energies and point out the need for a prescription to handle IR divergences induced by the nonlocality of the theory. We also calculate the tree level contribution to {mu} {yields} e + {gamma} from SIM(2) invariant mass terms.
Invariant Coordinates in Breakup Reactions
NASA Astrophysics Data System (ADS)
Skwira-Chalot, I.; Ciepał, I.; Kistryn, St.; Kozela, A.; Parol, W.; Stephan, E.
2017-03-01
Systematic experimental studies of few-nucleon systems expose various dynamical ingredients which play an important role in correct description of observables, such as three-nucleon force, Coulomb force and relativistic effects. A large set of existing experimental data for ^1H(d, p p)n reaction allows for systematic investigations of these dynamical effects, which vary with energy and appear with different strength in certain observables and phase space regions. Moreover, systematic comparisons with exact theoretical calculations, done in variables related to the system dynamics in a possibly direct ways is a very important tool to verify and improve the existing description of the nucleon interaction. Examples of experimental data for a breakup reaction, transformed to the variables based on Lorentz-invariants are compared with modern theoretical calculations.
Constraining Anisotropic Lorentz Violation via the Spectral-lag Transition of GRB 160625B
NASA Astrophysics Data System (ADS)
Wei, Jun-Jie; Wu, Xue-Feng; Zhang, Bin-Bin; Shao, Lang; Mészáros, Peter; Kostelecký, V. Alan
2017-06-01
Violations of Lorentz invariance can lead to an energy-dependent vacuum dispersion of light, which results in arrival-time differences of photons with different energies arising from a given transient source. In this work, direction-dependent dispersion constraints are obtained on nonbirefringent Lorentz-violating effects using the observed spectral lags of the gamma-ray burst GRB 160625B. This burst has unusually large high-energy photon statistics, so we can obtain constraints from the true spectral time lags of bunches of high-energy photons rather than from the rough time lag of a single highest-energy photon. Also, GRB 160625B is the only burst to date having a well-defined transition from positive lags to negative lags, providing a unique opportunity to distinguish Lorentz-violating effects from any source-intrinsic time lag in the emission of photons of different energy bands. Our results place comparatively robust two-sided constraints on a variety of isotropic and anisotropic coefficients for Lorentz violation, including the first bounds on Lorentz-violating effects from operators of mass dimension 10 in the photon sector.
Velocity addition and a closed time cycle in Lorentz-noninvariant theories
NASA Astrophysics Data System (ADS)
Shabad, A. E.
2016-06-01
In theories whose Lorentz invariance is violated by the presence of an external tensor of any rank, we show that a signal velocity, understood as the group velocity of a wave, is added to the velocity of the reference frame according to the standard relativistic rule for adding velocities. In the case where we have a superluminal signal, this observation allows creating a closed time cycle and thus coming to a conclusion about a causality violation even in the absence of relativistic invariance. We also reveal an optical anisotropy of a moving medium that is isotropic at rest.
CPT and lorentz tests with muons
Bluhm; Kostelecky; Lane
2000-02-07
Precision experiments with muons are sensitive to Planck-scale CPT and Lorentz violation that is undetectable in other tests. Existing data on the muonium ground-state hyperfine structure and on the muon anomalous magnetic moment could be analyzed to provide dimensionless figures of merit for CPT and Lorentz violation at the levels of 4x10(-21) and 10(-23).
Lorentz violation and deep inelastic scattering
NASA Astrophysics Data System (ADS)
Kostelecký, V. Alan; Lunghi, E.; Vieira, A. R.
2017-06-01
The effects of quark-sector Lorentz violation on deep inelastic electron-proton scattering are studied. We show that existing data can be used to establish first constraints on numerous coefficients for Lorentz violation in the quark sector at an estimated sensitivity of parts in a million.
Cosmological constraints on Lorentz violation in electrodynamics.
Kostelecký, V A; Mewes, M
2001-12-17
Infrared, optical, and ultraviolet spectropolarimetry of cosmological sources is used to constrain the pure electromagnetic sector of a general Lorentz-violating standard-model extension. The coefficients for Lorentz violation are bounded to less than 3 x 10(-32).
Noncommutative field theory and Lorentz violation.
Carroll, S M; Harvey, J A; Kostelecký, V A; Lane, C D; Okamoto, T
2001-10-01
The role of Lorentz symmetry in noncommutative field theory is considered. Any realistic noncommutative theory is found to be physically equivalent to a subset of a general Lorentz-violating standard-model extension involving ordinary fields. Some theoretical consequences are discussed. Existing experiments bound the scale of the noncommutativity parameter to (10 TeV)(-2).
Lorentz violation and deep inelastic scattering
Kostelecký, V. Alan; Lunghi, E.; Vieira, A. R.
2017-03-28
We study the effects of quark-sector Lorentz violation on deep inelastic electron–proton scattering. Here, we show that existing data can be used to establish first constraints on numerous coefficients for Lorentz violation in the quark sector at an estimated sensitivity of parts in a million.
Lorentz, Hendrik Antoon (1853-1928)
NASA Astrophysics Data System (ADS)
Murdin, P.
2000-11-01
Born in Arnhem, Netherlands, became professor of mathematical physics at Leiden University. Nobel prizewinner 1902, jointly with PIETER ZEEMAN, for his mathematical theory of the electron demonstrating the effect of a strong magnetic field on wavelength of the light produced by an atom (this was before the discovery of the electron). Lorentz's name is commemorated in the FitzGerald-Lorentz contra...
NASA Astrophysics Data System (ADS)
Toniolo, Giuliano R.; Fargnoli, H. G.; Brito, L. C. T.; Scarpelli, A. P. Baêta
2017-02-01
S-matrix amplitudes for the electron-electron scattering are calculated in order to verify the physical equivalence between two Lorentz-breaking dual models. We begin with an extended Quantum Electrodynamics which incorporates CPT-even Lorentz-violating kinetic and mass terms. Then, in a process of gauge embedding, its gauge-invariant dual model is obtained. The physical equivalence of the two models is established at tree level in the electron-electron scattering and the unpolarized cross section is calculated up to second order in the Lorentz-violating parameter.
Gluonic Lorentz violation and chiral perturbation theory
NASA Astrophysics Data System (ADS)
Noordmans, J. P.
2017-04-01
By applying chiral-perturbation-theory methods to the QCD sector of the Lorentz-violating Standard-Model Extension, we investigate Lorentz violation in the strong interactions. In particular, we consider the C P T -even pure-gluon operator of the minimal Standard-Model Extension. We construct the lowest-order chiral effective Lagrangian for three as well as two light quark flavors. We develop the power-counting rules and construct the heavy-baryon chiral-perturbation-theory Lagrangian, which we use to calculate Lorentz-violating contributions to the nucleon self-energy. Using the constructed effective operators, we derive the first stringent limits on many of the components of the relevant Lorentz-violating parameter. We also obtain the Lorentz-violating nucleon-nucleon potential. We suggest that this potential may be used to obtain new limits from atomic-clock or deuteron storage-ring experiments.
Recent advances in Lorentz microscopy
Phatak, C.; Petford-Long, A. K.; De Graef, M.
2016-01-05
Lorentz transmission electron microscopy (LTEM) has evolved from a qualitative magnetic domain observation technique to a quantitative technique for the determination of the magnetization state of a sample. Here, we describe recent developments in techniques and imaging modes, including the use of spherical aberration correction to improve the spatial resolution of LTEM into the single nanometer range, and novel in situ observation modes. We also review recent advances in the modeling of the wave optical magnetic phase shift as well as in the area of phase reconstruction by means of the Transport of Intensity Equation (TIE) approach, and discuss vectormore » field electron tomography, which has emerged as a powerful tool for the 3D reconstruction of magnetization configurations. Finally, we conclude this review with a brief overview of recent LTEM applications.« less
Recent advances in Lorentz microscopy
Phatak, C.; Petford-Long, A. K.; De Graef, M.
2016-01-05
Lorentz transmission electron microscopy (LTEM) has evolved from a qualitative magnetic domain observation technique to a quantitative technique for the determination of the magnetization state of a sample. Here, we describe recent developments in techniques and imaging modes, including the use of spherical aberration correction to improve the spatial resolution of LTEM into the single nanometer range, and novel in situ observation modes. We also review recent advances in the modeling of the wave optical magnetic phase shift as well as in the area of phase reconstruction by means of the Transport of Intensity Equation (TIE) approach, and discuss vector field electron tomography, which has emerged as a powerful tool for the 3D reconstruction of magnetization configurations. Finally, we conclude this review with a brief overview of recent LTEM applications.
Lorentz violation and perpetual motion
Eling, Christopher; Foster, Brendan Z.; Jacobson, Ted; Wall, Aron C.
2007-05-15
We show that any Lorentz-violating theory with two or more propagation speeds is in conflict with the generalized second law of black hole thermodynamics. We do this by identifying a classical energy-extraction method, analogous to the Penrose process, which would decrease the black hole entropy. Although the usual definitions of black hole entropy are ambiguous in this context, we require only very mild assumptions about its dependence on the mass. This extends the result found by Dubovsky and Sibiryakov, which uses the Hawking effect and applies only if the fields with different propagation speeds interact just through gravity. We also point out instabilities that could interfere with their black hole perpetuum mobile, but argue that these can be neglected if the black hole mass is sufficiently large.
Lorentz violation and perpetual motion
NASA Astrophysics Data System (ADS)
Eling, Christopher; Foster, Brendan Z.; Jacobson, Ted; Wall, Aron C.
2007-05-01
We show that any Lorentz-violating theory with two or more propagation speeds is in conflict with the generalized second law of black hole thermodynamics. We do this by identifying a classical energy-extraction method, analogous to the Penrose process, which would decrease the black hole entropy. Although the usual definitions of black hole entropy are ambiguous in this context, we require only very mild assumptions about its dependence on the mass. This extends the result found by Dubovsky and Sibiryakov, which uses the Hawking effect and applies only if the fields with different propagation speeds interact just through gravity. We also point out instabilities that could interfere with their black hole perpetuum mobile, but argue that these can be neglected if the black hole mass is sufficiently large.
Eikonal equation of the Lorentz-violating Maxwell theory
NASA Astrophysics Data System (ADS)
Xiao, Zhi; Shao, Lijing; Ma, Bo-Qiang
2010-12-01
We derive the eikonal equation of light wavefront in the presence of Lorentz invariance violation (LIV) from the photon sector of the standard model extension (SME). The results obtained from the equations of the E and B fields, respectively, are the same. This guarantees the self-consistency of our derivation. We adopt a simple case with only one non-zero LIV parameter as an illustration, from which we find two points. One is that, in analogy with the Hamilton-Jacobi equation, from the eikonal equation, we can derive dispersion relations which are compatible with results obtained from other approaches. The other is that the wavefront velocity is the same as the group velocity, as well as the energy flow velocity. If further we define the signal velocity v s as the front velocity, there always exists a mode with v s >1; hence causality is violated classically. Thus, our method might be useful in the analysis of Lorentz violation in QED in terms of classical causality.
Cosmic censorship in Lorentz-violating theories of gravity
NASA Astrophysics Data System (ADS)
Meiers, Michael; Saravani, Mehdi; Afshordi, Niayesh
2016-05-01
Is cosmic censorship special to general relativity, or can it survive a violation of local Lorentz invariance? Recent studies have shown that singularities in Lorentz -violating Einstein-Aether (or Horava-Lifshitz) theories can lie behind a universal horizon in simple black hole spacetimes. Even infinitely fast signals cannot escape these universal horizons. We extend this result, for an incompressible aether, to 3 +1 d dynamical or spinning spacetimes which possess inner Killing horizons, and show that a universal horizon always forms in between the outer and (would-be) inner horizons. This finding suggests a notion of cosmic censorship, given that geometry in these theories never evolves beyond the universal horizon (avoiding potentially singular inner Killing horizons). A surprising result is that there are 3 distinct possible stationary universal horizons for a spinning black hole, only one of which matches the dynamical spherical solution. This motivates dynamical studies of collapse in Einstein-Aether theories beyond spherical symmetry, which may reveal instabilities around the spherical solution.
Inflation as an amplifier: The case of Lorentz violation
NASA Astrophysics Data System (ADS)
Bonder, Yuri; León, Gabriel
2017-08-01
Modified gravity theories are supposed to incorporate low-energy quantum-gravity effects and, at the same time, they could shed light into the dark matter and dark energy problems. Here we study a particular modification of general relativity where local Lorentz invariance is spontaneously broken and whose physical effects, despite a decade-long effort, were unknown. We show that, during inflation, this modification produces anisotropies that would generate measurable effects on the cosmic microwave background. Then, by using empirical constraints on the B-mode polarization spectrum, we can estimate that the "coefficient" components absolute value have to be smaller than 10-43. This is a remarkably strong limit; in fact, it is 29 orders of magnitude better than the best constraints on similar coefficients. Thus, we propose that inflation could stringently test other modified gravity theories.
Magnetic field contribution to the Lorentz model.
Oughstun, Kurt E; Albanese, Richard A
2006-07-01
The classical Lorentz model of dielectric dispersion is based on the microscopic Lorentz force relation and Newton's second law of motion for an ensemble of harmonically bound electrons. The magnetic field contribution in the Lorentz force relation is neglected because it is typically small in comparison with the electric field contribution. Inclusion of this term leads to a microscopic polarization density that contains both perpendicular and parallel components relative to the plane wave propagation vector. The modified parallel and perpendicular polarizabilities are both nonlinear in the local electric field strength.
Lorentz covariant {kappa}-Minkowski spacetime
DaPbrowski, Ludwik; Godlinski, Michal; Piacitelli, Gherardo
2010-06-15
In recent years, different views on the interpretation of Lorentz covariance of noncommuting coordinates have been discussed. By a general procedure, we construct the minimal canonical central covariantization of the {kappa}-Minkowski spacetime. Here, undeformed Lorentz covariance is implemented by unitary operators, in the presence of two dimensionful parameters. We then show that, though the usual {kappa}-Minkowski spacetime is covariant under deformed (or twisted) Lorentz action, the resulting framework is equivalent to taking a noncovariant restriction of the covariantized model. We conclude with some general comments on the approach of deformed covariance.
Abraham-Lorentz versus Landau-Lifshitz
NASA Astrophysics Data System (ADS)
Griffiths, David J.; Proctor, Thomas C.; Schroeter, Darrell F.
2010-04-01
The classical Abraham-Lorentz formula for the radiation reaction on a point charge suffers from two notorious defects: runaways and preacceleration. Recently, several authors have advocated as an alternative the Landau-Lifshitz formula, which has neither fault. The latter formula is often presented as an approximation to Abraham-Lorentz, raising the delicate question of how an approximation can be considered more accurate than the original. For a spherical shell of finite size, the equation for the radiation reaction is noncontroversial. We begin there, obtain the Abraham-Lorentz and Landau-Lifshitz expressions as limiting cases, and undertake some numerical studies to determine which is superior.
Effects of Lorentz violation through the γe → Wνe process in the Standard Model extension
NASA Astrophysics Data System (ADS)
Aranda, J. I.; Ramírez-Zavaleta, F.; Rosete, D. A.; Tlachino, F. J.; Toscano, J. J.; Tututi, E. S.
2014-05-01
Physics beyond the Fermi scale could show up through deviations of the gauge couplings predicted by the electroweak Yang-Mills sector. This possibility is explored in the context of the International Linear Collider through the helicity amplitudes for the γe → Wνe reaction to which the trilinear WWγ coupling contributes. The new physics effects on this vertex are parametrized in a model-independent fashion through an effective electroweak Yang-Mills sector, which is constructed by considering two essentially different sources of new physics. In one scenario, Lorentz violation will be considered exclusively as the source of new physics effects. This type of new physics is considered in an extension of the Standard Model (SM) that is known as the SM extension (SME), which is an effective field theory that contemplates CPT and Lorentz violation in a model-independent fashion. Any source of new physics that respects the Lorentz symmetry will be considered within the general context of the well-known conventional effective SM (CESM) extension. Both the SME and CESM descriptions include gauge invariant operators of dimension higher than 4, which, in general, transform as Lorentz tensors of rank higher than zero. In the former theory, observer Lorentz invariants are constructed by contracting these operators with constant Lorentz tensors, whereas in the latter the corresponding Lorentz invariant interactions are obtained contracting such operators with products of the metric tensor. In this work, we focus on a dimension 6 Lorentz 2-tensor, O_{\\alpha \\beta }, which arises from an effective SU(2)L Yang-Mills sector. Contributions to the WWγ coupling arising from dimension 4 operators are ignored since they are strongly constrained. When these operators are contracted with a constant antisymmetric background tensor, bαβ, the corresponding observer invariant belongs to the SME, whereas if they are contracted with the metric tensor, gαβ, an effective interaction in
Searches for Lorentz Violation in Top-Quark Production and Decay at Hadron Colliders
Whittington, Denver Wade
2012-07-01
We present a first-of-its-kind confirmation that the most massive known elementary particle obeys the special theory of relativity. Lorentz symmetry is a fundamental aspect of special relativity which posits that the laws of physics are invariant regardless of the orientation and velocity of the reference frame in which they are measured. Because this symmetry is a fundamental tenet of physics, it is important to test its validity in all processes. We quantify violation of this symmetry using the Standard-Model Extension framework, which predicts the effects that Lorentz violation would have on elementary particles and their interactions. The top quark is the most massive known elementary particle and has remained inaccessible to tests of Lorentz invariance until now. This model predicts a dependence of the production cross section for top and antitop quark pairs on sidereal time as the orientation of the experiment in which these events are produced changes with the rotation of the Earth. Using data collected with the DØ detector at the Fermilab Tevatron Collider, we search for violation of Lorentz invariance in events involving the production of a $t\\bar{t}$ pair. Within the experimental precision, we find no evidence for such a violation and set upper limits on parameters describing its possible strength within the Standard-Model Extension. We also investigate the prospects for extending this analysis using the ATLAS detector at the Large Hadron Collider which, because of the higher rate of $t\\bar{t}$ events at that experiment, has the potential to improve the limits presented here.
Tests of Local Position Invariance Using Continuously Running Atomic Clocks
2013-01-22
principle) and that nongravitational measurements should be independent of the velocity of the freely falling reference frame (local Lorentz invariance...be independent of the clock composition, for example. Violation of LPI may manifest itself in an anomalous gravitational redshift of an atomic clock... violating parameters β1 and β2, the relative frequencies should vary with the gravitational potential as (ν/ν)1,2 = (β1 − β2)U/c2. (2) *steven.peil
Lorentz Transformation from Symmetry of Reference Principle
Petre, M.; Dima, M.; Dima, A.; Petre, C.; Precup, I.
2010-01-21
The Lorentz Transformation is traditionally derived requiring the Principle of Relativity and light-speed universality. While the latter can be relaxed, the Principle of Relativity is seen as core to the transformation. The present letter relaxes both statements to the weaker, Symmetry of Reference Principle. Thus the resulting Lorentz transformation and its consequences (time dilatation, length contraction) are, in turn, effects of how we manage space and time.
Gauge anomalies in Lorentz-violating QED
NASA Astrophysics Data System (ADS)
Santos, Tiago R. S.; Sobreiro, Rodrigo F.
2016-12-01
In this work we study the issue of gauge anomalies in Lorentz-violating QED. To do so, we opt to use the Becchi-Rouet-Stora-Tyutin formalism within the algebraic renormalization approach, reducing our study to a cohomology problem. Since this approach is independent of the renormalization scheme, the results obtained here are expected to be general. We find that the Lorentz-violating QED is free of gauge anomalies to all orders in perturbation theory.
Broken boost invariance in the Glasma via finite nuclei thickness
NASA Astrophysics Data System (ADS)
Ipp, Andreas; Müller, David
2017-08-01
We simulate the creation and evolution of non-boost-invariant Glasma in the early stages of heavy ion collisions within the color glass condensate framework. This is accomplished by extending the McLerran-Venugopalan model to include a parameter for the Lorentz-contracted but finite width of the nucleus in the beam direction. We determine the rapidity profile of the Glasma energy density, which shows deviations from the boost-invariant result. Varying the parameters both broad and narrow profiles can be produced. We compare our results to experimental data from RHIC and find surprising agreement.
Hadronic Lorentz violation in chiral perturbation theory
NASA Astrophysics Data System (ADS)
Kamand, Rasha; Altschul, Brett; Schindler, Matthias R.
2017-03-01
Any possible Lorentz violation in the hadron sector must be tied to Lorentz violation at the underlying quark level. The relationships between the theories at these two levels are studied using chiral perturbation theory. Starting from a two-flavor quark theory that includes dimension-4 Lorentz-violation operators, the effective Lagrangians are derived for both pions and nucleons, with novel terms appearing in both sectors. Since the Lorentz-violation coefficients for nucleons and pions are all related to a single set of underlying quark coefficients, one can compare the sensitivity of different types of experiments. Our analysis shows that atomic physics experiments currently provide constraints on the quark parameters that are stronger by about 10 orders of magnitude than astrophysical experiments with relativistic pions. Alternatively, it is possible to place approximate bounds on pion Lorentz violation using only proton and neutron observations. Under the assumption that the Lorentz-violating operators considered here are the only ones contributing to the relevant observables and taking the currently unknown hadronic low-energy constants to be of natural size, the resulting estimated bounds on four pion parameters are at the 10-23 level, representing improvements of 10 orders of magnitude.
Lorentz violating supersymmetric quantum electrodynamics
Bolokhov, Pavel A.; Groot Nibbelink, Stefan; Pospelov, Maxim
2005-07-01
The theory of supersymmetric quantum electrodynamics is extended by interactions with external vector and tensor backgrounds, that are assumed to be generated by some Lorentz-violating (LV) dynamics at an ultraviolet scale perhaps related to the Planck scale. Exact supersymmetry requires that such interactions correspond to LV operators of dimension five or higher, providing a solution to the naturalness problem in the LV sector. We classify all dimension five and six LV operators, analyze their properties at the quantum level and describe observational consequences of LV in this theory. We show that LV operators do not induce destabilizing D-terms, gauge anomaly, and the Chern-Simons term for photons. We calculate the renormalization group evolution of dimension five LV operators and their mixing with dimension three LV operators, controlled by the scale of the soft-breaking masses. Dimension five LV operators are constrained by low-energy precision measurements at 10{sup -10}-10{sup -5} level in units of the inverse Planck scale, while the Planck-scale suppressed dimension six LV operators are allowed by observational data.
Spectra of Lorentz-violating Dirac bound states in a cylindrical well
NASA Astrophysics Data System (ADS)
Xiao, Zhi
2016-12-01
In the presence of the Lorentz-violating bμ coefficient, the spectra of bound states for a Dirac particle in a cylindric well are changed. Compared to the Lorentz invariant (LI) spectrum, the Lorentz violation deviation becomes significant when eigenenergy E is sufficiently close to the critical values ±m , where m is the particle's mass. The detailed profile of the deviation depends on the observer Lorentz nature of bμ. We discussed three types of bμ configuration. When bμ=(0 ,0 ,0 ,bZ) is parallel to the well axis, the would be degenerate LI spectra split into two subspectra, reminiscent of the Zeeman splitting in the presence of a weak magnetic field. Depending on the relative sign of bZ accompanying mass m in the dispersion relation, the spectrum extends or shrinks in the allowed eigenenergy region. When bμ is a radial [bμ=(0 ,b cos ϕ ,b sin ϕ ,0 ) ] or purely timelike vector [bμ=(bT,0 →)], the spin-up and down components are coupled together, and there is no splitting. However, the monotonic increasing behavior of well depth V0 with the decrease of eigenenergy E is slightly changed when E is sufficiently close to -m .
An operational approach to spacetime symmetries: Lorentz transformations from quantum communication
NASA Astrophysics Data System (ADS)
Höhn, Philipp A.; Müller, Markus P.
2016-06-01
In most approaches to fundamental physics, spacetime symmetries are postulated a priori and then explicitly implemented in the theory. This includes Lorentz covariance in quantum field theory and diffeomorphism invariance in quantum gravity, which are seen as fundamental principles to which the final theory has to be adjusted. In this paper, we suggest, within a much simpler setting, that this kind of reasoning can actually be reversed, by taking an operational approach inspired by quantum information theory. We consider observers in distinct laboratories, with local physics described by the laws of abstract quantum theory, and without presupposing a particular spacetime structure. We ask what information-theoretic effort the observers have to spend to synchronize their descriptions of local physics. If there are ‘enough’ observables that can be measured universally on several different quantum systems, we show that the observers’ descriptions are related by an element of the orthochronous Lorentz group {{{O}}}+(3,1), together with a global scaling factor. Not only does this operational approach predict the Lorentz transformations, but it also accurately describes the behavior of relativistic Stern-Gerlach devices in the WKB approximation, and it correctly predicts that quantum systems carry Lorentz group representations of different spin. This result thus hints at a novel information-theoretic perspective on spacetime.
Scale invariance, conformality, and generalized free fields
Dymarsky, Anatoly; Farnsworth, Kara; Komargodski, Zohar; ...
2016-02-16
This paper addresses the question of whether there are 4D Lorentz invariant unitary quantum fi eld theories with scale invariance but not conformal invariance. We present an important loophole in the arguments of Luty-Polchinski-Rattazzi and Dymarsky-Komargodski-Schwimmer-Theisen that is the trace of the energy-momentum tensor T could be a generalized free field. In this paper we rule out this possibility. The key ingredient is the observation that a unitary theory with scale but not conformal invariance necessarily has a non-vanishing anomaly for global scale transformations. We show that this anomaly cannot be reproduced if T is a generalized free field unlessmore » the theory also contains a dimension-2 scalar operator. In the special case where such an operator is present it can be used to redefine ("improve") the energy-momentum tensor, and we show that there is at least one energy-momentum tensor that is not a generalized free field. In addition, we emphasize that, in general, large momentum limits of correlation functions cannot be understood from the leading terms of the coordinate space OPE. This invalidates a recent argument by Farnsworth-Luty-Prilepina (FLP). Finally, despite the invalidity of the general argument of FLP, some of the techniques turn out to be useful in the present context.« less
Scale invariance, conformality, and generalized free fields
Dymarsky, Anatoly; Farnsworth, Kara; Komargodski, Zohar; Luty, Markus A.; Prilepina, Valentina
2016-02-16
This paper addresses the question of whether there are 4D Lorentz invariant unitary quantum fi eld theories with scale invariance but not conformal invariance. We present an important loophole in the arguments of Luty-Polchinski-Rattazzi and Dymarsky-Komargodski-Schwimmer-Theisen that is the trace of the energy-momentum tensor T could be a generalized free field. In this paper we rule out this possibility. The key ingredient is the observation that a unitary theory with scale but not conformal invariance necessarily has a non-vanishing anomaly for global scale transformations. We show that this anomaly cannot be reproduced if T is a generalized free field unless the theory also contains a dimension-2 scalar operator. In the special case where such an operator is present it can be used to redefine ("improve") the energy-momentum tensor, and we show that there is at least one energy-momentum tensor that is not a generalized free field. In addition, we emphasize that, in general, large momentum limits of correlation functions cannot be understood from the leading terms of the coordinate space OPE. This invalidates a recent argument by Farnsworth-Luty-Prilepina (FLP). Finally, despite the invalidity of the general argument of FLP, some of the techniques turn out to be useful in the present context.
Hohensee, M A; Leefer, N; Budker, D; Harabati, C; Dzuba, V A; Flambaum, V V
2013-08-02
We report a joint test of local Lorentz invariance and the Einstein equivalence principle for electrons, using long-term measurements of the transition frequency between two nearly degenerate states of atomic dysprosium. We present many-body calculations which demonstrate that the energy splitting of these states is particularly sensitive to violations of both special and general relativity. We limit Lorentz violation for electrons at the level of 10(-17), matching or improving the best laboratory and astrophysical limits by up to a factor of 10, and improve bounds on gravitational redshift anomalies for electrons by 2 orders of magnitude, to 10(-8). With some enhancements, our experiment may be sensitive to Lorentz violation at the level of 9 × 10(-20).
Kazinski, P O; Shipulya, M A
2011-06-01
We present a study of planar physical solutions to the Lorentz-Dirac equation in a constant electromagnetic field. In this case, we reduced the Lorentz-Dirac equation to one second-order differential equation. We obtained the asymptotics of physical solutions to this equation at large proper times. It turns out that, in a crossed constant uniform electromagnetic field with vanishing invariants, a charged particle enters a universal regime at large times. We found that the ratios of momentum components that tend to constants are determined only by the external field. This effect is essentially due to a radiation reaction. There is no such effect for the Lorentz equation in this field.
Generation and classification of localized waves by Lorentz transformations in Fourier space.
Saari, Peeter; Reivelt, Kaido
2004-03-01
The Lorentz transformations of propagation-invariant localized waves (also known as nondispersive or nondiffracting or undistorted progressive waves) are studied in the frequency-momentum space. For supports of wave functions in this space rules of transformation are derived which allow one to group all localized waves into distinct classes: subluminal, luminal, and superluminal localized waves. It is shown that for each class there is an inertial frame in which any given localized wave takes a particularly simple form. In other words, any localized wave is nothing but a relativistically aberrant and Doppler shifted version of a simple "seed" wave. Also discussed are the relations of the physical (subluminal) Lorentz tranformation to other mathematical tranformations used in the literature on localized waves, as well as physical interpretation of the substantial changes that localized waves undergo if observed and generated in different inertial frames.
The photino sector and a confining potential in a supersymmetric Lorentz-symmetry-violating model
NASA Astrophysics Data System (ADS)
Belich, H.; Bernald, L. D.; Gaete, Patricio; Helayël-Neto, J. A.
2013-11-01
We study the spectrum of the minimal supersymmetric extension of the Carroll-Field-Jackiw model for Electrodynamics with a topological Chern-Simons-like Lorentz-symmetry violating term. We identify a number of independent background fermion condensates, work out the gaugino dispersion relation and propose a photonic effective action to consider aspects of confinement induced by the SUSY background fermion condensates, which also appear to signal Lorentz-symmetry violation in the photino sector of the action. Our calculations of the static potential are carried out within the framework of the gauge-invariant but path-dependent variables formalism which are alternative to the Wilson loop approach. Our results show that the interaction energy contains a linear term leading to the confinement of static probe charges.
NASA Astrophysics Data System (ADS)
Wu, Yi-Peng
2016-11-01
Arbitrary generalization to the teleparallel equivalent of general relativity loses local Lorentz invariance to reparametrize the orthonormal coordinate system and gives rise to asymmetry field equations. We investigate consequences of local Lorentz violation to primordial fluctuations in extended single field inflationary models based on the scalar-tensor formulation of the torsion scalar T that effectively includes f (T) gravity as a special case. We show that despite some asymmetry part of the field equations are removed in a spatially homogeneous and isotropic cosmic background, no subhorizon scalar-perturbation mode can survive by the time of horizon crossing. As a result, any scalar field mediated in torsion cannot generate enough primordial density inhomogeneity alone, even if it brings some de Sitter background solutions in generalized teleparallel gravity.
Optimal embeddings of Bessel and Riesz type potentials on the basis of weighted Lorentz spaces
NASA Astrophysics Data System (ADS)
Karshygina, Gulden Zh.
2017-09-01
We study a space of potentials on the n-dimensional Euclidean space. They are constructed on the basis of rearrangement invariant spaces (RISs) by means of convolutions with kernels of general form. In particular, the spaces of classical potentials of Bessel and Riesz are included in the discussion. We establish the integral properties of potentials. For them the criteria for embedding in the RIS are found and explicit descriptions of the optimal RIS for these embeddings are obtained in case of the basic weighted Lorentz space. The aim of this paper is to give an explicit description of the optimal RIS X(Rn) for embeddings HEG(Rn)⊂X (Rn) in the case when the base RIS E(Rn) coincides with the weighted Lorentz space Λp(u).
Generalizing twisted gauge invariance
Duenas-Vidal, Alvaro; Vazquez-Mozo, Miguel A.
2009-05-01
We discuss the twisting of gauge symmetry in noncommutative gauge theories and show how this can be generalized to a whole continuous family of twisted gauge invariances. The physical relevance of these twisted invariances is discussed.
NASA Astrophysics Data System (ADS)
Delgado Acosta, E. G.; Banda Guzmán, V. M.; Kirchbach, M.
2015-03-01
We propose a general method for the description of arbitrary single spin- j states transforming according to ( j, 0) ⊕ (0, j) carrier spaces of the Lorentz algebra in terms of Lorentz tensors for bosons, and tensor-spinors for fermions, and by means of second-order Lagrangians. The method allows to avoid the cumbersome matrix calculus and higher ∂2 j order wave equations inherent to the Weinberg-Joos approach. We start with reducible Lorentz tensor (tensor-spinor) representation spaces hosting one sole ( j, 0) ⊕ (0, j) irreducible sector and design there a representation reduction algorithm based on one of the Casimir invariants of the Lorentz algebra. This algorithm allows us to separate neatly the pure spin- j sector of interest from the rest, while preserving the separate Lorentz and Dirac indexes. However, the Lorentz invariants are momentum independent and do not provide wave equations. Genuine wave equations are obtained by conditioning the Lorentz tensors under consideration to satisfy the Klein-Gordon equation. In so doing, one always ends up with wave equations and associated Lagrangians that are of second order in the momenta. Specifically, a spin-3/2 particle transforming as (3/2, 0) ⊕ (0, 3/2) is comfortably described by a second-order Lagrangian in the basis of the totally anti-symmetric Lorentz tensor-spinor of second rank, Ψ [ μν]. Moreover, the particle is shown to propagate causally within an electromagnetic background. In our study of (3/2, 0) ⊕ (0, 3/2) as part of Ψ [ μν] we reproduce the electromagnetic multipole moments known from the Weinberg-Joos theory. We also find a Compton differential cross-section that satisfies unitarity in forward direction. The suggested tensor calculus presents itself very computer friendly with respect to the symbolic software FeynCalc.
Baryogenesis in Lorentz-violating gravity theories
NASA Astrophysics Data System (ADS)
Sakstein, Jeremy; Solomon, Adam R.
2017-10-01
Lorentz-violating theories of gravity typically contain constrained vector fields. We show that the lowest-order coupling of such vectors to U (1)-symmetric scalars can naturally give rise to baryogenesis in a manner akin to the Affleck-Dine mechanism. We calculate the cosmology of this new mechanism, demonstrating that a net B - L can be generated in the early Universe, and that the resulting baryon-to-photon ratio matches that which is presently observed. We discuss constraints on the model using solar system and astrophysical tests of Lorentz violation in the gravity sector. Generic Lorentz-violating theories can give rise to the observed matter-antimatter asymmetry without violating any current bounds.
Maps for Lorentz transformations of spin
Jordan, Thomas F.; Shaji, Anil; Sudarshan, E. C. G.
2006-03-15
Lorentz transformations of spin density matrices for a particle with positive mass and spin 1/2 are described by maps of the kind used in open quantum dynamics. They show how the Lorentz transformations of the spin depend on the momentum. Since the spin and momentum generally are not independent, the maps generally are not completely positive and act in limited domains. States with two momentum values are considered, so the maps are for the spin qubit correlated with the qubit made from the two momentum values, and results from the open quantum dynamics of two coupled qubits can be applied. Inverses are used to show that every Lorentz transformation completely removes the spin polarization, and so completely removes the information, from a number of spin density matrices. The size of the spin polarization that is removed is calculated for particular cases.
Aberration corrected Lorentz scanning transmission electron microscopy.
McVitie, S; McGrouther, D; McFadzean, S; MacLaren, D A; O'Shea, K J; Benitez, M J
2015-05-01
We present results from an aberration corrected scanning transmission electron microscope which has been customised for high resolution quantitative Lorentz microscopy with the sample located in a magnetic field free or low field environment. We discuss the innovations in microscope instrumentation and additional hardware that underpin the imaging improvements in resolution and detection with a focus on developments in differential phase contrast microscopy. Examples from materials possessing nanometre scale variations in magnetisation illustrate the potential for aberration corrected Lorentz imaging as a tool to further our understanding of magnetism on this lengthscale.
Imperfect fluids, Lorentz violations, and Finsler cosmology
Kouretsis, A. P.; Stathakopoulos, M.; Stavrinos, P. C.
2010-09-15
We construct a cosmological toy model based on a Finslerian structure of space-time. In particular, we are interested in a specific Finslerian Lorentz violating theory based on a curved version of Cohen and Glashow's very special relativity. The osculation of a Finslerian manifold to a Riemannian manifold leads to the limit of relativistic cosmology, for a specified observer. A modified flat Friedmann-Robertson-Walker cosmology is produced. The analogue of a zero energy particle unfolds some special properties of the dynamics. The kinematical equations of motion are affected by local anisotropies. Seeds of Lorentz violations may trigger density inhomogeneities to the cosmological fluid.
Black Hole Thermodynamics and Lorentz Symmetry
NASA Astrophysics Data System (ADS)
Jacobson, Ted; Wall, Aron C.
2010-08-01
Recent developments point to a breakdown in the generalized second law of thermodynamics for theories with Lorentz symmetry violation. It appears possible to construct a perpetual motion machine of the second kind in such theories, using a black hole to catalyze the conversion of heat to work. Here we describe and extend the arguments leading to that conclusion. We suggest the inference that local Lorentz symmetry may be an emergent property of the macroscopic world with origins in a microscopic second law of causal horizon thermodynamics.
Lorentz-violating electrodynamics and the cosmic microwave background.
Kostelecký, V Alan; Mewes, Matthew
2007-07-06
Possible Lorentz-violating effects in the cosmic microwave background are studied. We provide a systematic classification of renormalizable and nonrenormalizable operators for Lorentz violation in electrodynamics and use polarimetric observations to search for the associated violations.
A New Lorentz Violating Nonlocal Field Theory From String-Theory
Ganor, Ori J.
2007-10-04
A four-dimensional field theory with a qualitatively new type of nonlocality is constructed from a setting where Kaluza-Klein particles probe toroidally compactified string theory with twisted boundary conditions. In this theory fundamental particles are not pointlike and occupy a volume proportional to their R-charge. The theory breaks Lorentz invariance but appears to preserve spatial rotations. At low energies, it is approximately N=4 Super Yang-Mills theory, deformed by an operator of dimension seven. The dispersion relation of massless modes in vacuum is unchanged, but under certain conditions in this theory, particles can travel at superluminal velocities.
The Lorentz Theory of Electrons and Einstein's Theory of Relativity
ERIC Educational Resources Information Center
Goldberg, Stanley
1969-01-01
Traces the development of Lorentz's theory of electrons as applied to the problem of the electrodynamics of moving bodies. Presents evidence that the principle of relativity did not play an important role in Lorentz's theory, and that though Lorentz eventually acknowledged Einstein's work, he was unwilling to completely embrace the Einstein…
The Lorentz Theory of Electrons and Einstein's Theory of Relativity
ERIC Educational Resources Information Center
Goldberg, Stanley
1969-01-01
Traces the development of Lorentz's theory of electrons as applied to the problem of the electrodynamics of moving bodies. Presents evidence that the principle of relativity did not play an important role in Lorentz's theory, and that though Lorentz eventually acknowledged Einstein's work, he was unwilling to completely embrace the Einstein…
Gravity, Lorentz violation, and the standard model
NASA Astrophysics Data System (ADS)
Kostelecký, V. Alan
2004-05-01
The role of the gravitational sector in the Lorentz- and CPT-violating standard-model extension (SME) is studied. A framework is developed for addressing this topic in the context of Riemann-Cartan spacetimes, which include as limiting cases the usual Riemann and Minkowski geometries. The methodology is first illustrated in the context of the QED extension in a Riemann-Cartan background. The full SME in this background is then considered, and the leading-order terms in the SME action involving operators of mass dimension three and four are constructed. The incorporation of arbitrary Lorentz and CPT violation into general relativity and other theories of gravity based on Riemann-Cartan geometries is discussed. The dominant terms in the effective low-energy action for the gravitational sector are provided, thereby completing the formulation of the leading-order terms in the SME with gravity. Explicit Lorentz symmetry breaking is found to be incompatible with generic Riemann-Cartan geometries, but spontaneous Lorentz breaking evades this difficulty.
Lorentz Contraction and Current-Carrying Wires
ERIC Educational Resources Information Center
van Kampen, Paul
2008-01-01
The force between two parallel current-carrying wires is investigated in the rest frames of the ions and the electrons. A straightforward Lorentz transformation shows that what appears as a purely magnetostatic force in the ion frame appears as a combined magnetostatic and electrostatic force in the electron frame. The derivation makes use of a…
Electromagnetohydrodynamic modeling of Lorentz Effect Imaging
NASA Astrophysics Data System (ADS)
Pourtaheri, Navid; Truong, Trong-Kha; Henriquez, Craig S.
2013-11-01
Lorentz Effect Imaging (LEI) is an MRI technique that has been proposed for direct imaging of neuronal activity. While promising results have been obtained in phantoms and in the human median nerve in vivo, its contrast mechanism is still not fully understood. In this paper, computational model simulations were used to investigate how electromagnetohydrodynamics (EMHD) may explain the LEI contrast.
Lorentz-covariant dissipative Lagrangian systems
NASA Technical Reports Server (NTRS)
Kaufman, A. N.
1985-01-01
The concept of dissipative Hamiltonian system is converted to Lorentz-covariant form, with evolution generated jointly by two scalar functionals, the Lagrangian action and the global entropy. A bracket formulation yields the local covariant laws of energy-momentum conservation and of entropy production. The formalism is illustrated by a derivation of the covariant Landau kinetic equation.
Lorentz-covariant dissipative Lagrangian systems
NASA Technical Reports Server (NTRS)
Kaufman, A. N.
1985-01-01
The concept of dissipative Hamiltonian system is converted to Lorentz-covariant form, with evolution generated jointly by two scalar functionals, the Lagrangian action and the global entropy. A bracket formulation yields the local covariant laws of energy-momentum conservation and of entropy production. The formalism is illustrated by a derivation of the covariant Landau kinetic equation.
Another route to the Lorentz transformations
NASA Astrophysics Data System (ADS)
Bessonov, E. G.
2016-05-01
This paper uses the Galilean relativity principle and the dependence of the rate of a clock on its velocity to derive the Lorentz transformations (LTs). Analyzing different ways of deriving the LTs provides different perspectives on them and their implications, as well as making them more accessible to a wide range of readers with an interest in relativistic physics.
Vector models of gravitational Lorentz symmetry breaking
Seifert, Michael D.
2009-06-15
Spontaneous Lorentz symmetry breaking can occur when the dynamics of a tensor field cause it to take on a nonzero expectation value in vacuo, thereby providing one or more 'preferred directions' in spacetime. Couplings between such fields and spacetime curvature will then affect the dynamics of the metric, leading to interesting gravitational effects. Bailey and Kostelecky[Q. G. Bailey and V. A. Kostelecky, Phys. Rev. D 74, 045001 (2006)] developed a post-Newtonian formalism that, under certain conditions concerning the field's couplings and stress-energy, allows for the analysis of gravitational effects in the presence of Lorentz symmetry breaking. We perform a systematic survey of vector models of spontaneous Lorentz symmetry breaking. We find that a two-parameter class of vector models, those with kinetic terms we call 'pseudo-Maxwell', can be successfully analyzed under the Bailey-Kostelecky formalism, and that one of these two 'dimensions' in parameter space has not yet been explored as a possible mechanism of spontaneous Lorentz symmetry breaking.
Lorentz Contraction and Current-Carrying Wires
ERIC Educational Resources Information Center
van Kampen, Paul
2008-01-01
The force between two parallel current-carrying wires is investigated in the rest frames of the ions and the electrons. A straightforward Lorentz transformation shows that what appears as a purely magnetostatic force in the ion frame appears as a combined magnetostatic and electrostatic force in the electron frame. The derivation makes use of a…
Local Lorentz transformations and Thomas effect in general relativity
NASA Astrophysics Data System (ADS)
Silenko, Alexander J.
2016-06-01
The tetrad method is used for an introduction of local Lorentz frames and a detailed analysis of local Lorentz transformations. A formulation of equations of motion in local Lorentz frames is based on the Pomeransky-Khriplovich gravitoelectromagnetic fields. These fields are calculated in the most important special cases and their local Lorentz transformations are determined. The local Lorentz transformations and the Pomeransky-Khriplovich gravitoelectromagnetic fields are applied for a rigorous derivation of a general equation for the Thomas effect in Riemannian spacetimes and for a consideration of Einstein's equivalence principle and the Mathisson force.
Lorentz-violating type-II Dirac fermions in transition metal dichalcogenide PtTe2.
Yan, Mingzhe; Huang, Huaqing; Zhang, Kenan; Wang, Eryin; Yao, Wei; Deng, Ke; Wan, Guoliang; Zhang, Hongyun; Arita, Masashi; Yang, Haitao; Sun, Zhe; Yao, Hong; Wu, Yang; Fan, Shoushan; Duan, Wenhui; Zhou, Shuyun
2017-08-15
Topological semimetals have recently attracted extensive research interests as host materials to condensed matter physics counterparts of Dirac and Weyl fermions originally proposed in high energy physics. Although Lorentz invariance is required in high energy physics, it is not necessarily obeyed in condensed matter physics, and thus Lorentz-violating type-II Weyl/Dirac fermions could be realized in topological semimetals. The recent realization of type-II Weyl fermions raises the question whether their spin-degenerate counterpart-type-II Dirac fermions-can be experimentally realized too. Here, we report the experimental evidence of type-II Dirac fermions in bulk stoichiometric PtTe2 single crystal. Angle-resolved photoemission spectroscopy measurements and first-principles calculations reveal a pair of strongly tilted Dirac cones along the Γ-A direction, confirming PtTe2 as a type-II Dirac semimetal. Our results provide opportunities for investigating novel quantum phenomena (e.g., anisotropic magneto-transport) and topological phase transition.Whether the spin-degenerate counterpart of Lorentz-violating Weyl fermions, the Dirac fermions, can be realized remains as an open question. Here, Yan et al. report experimental evidence of such type-II Dirac fermions in bulk PtTe2 single crystal with a pair of strongly tilted Dirac cones.
A New Limit on Planck Scale Lorentz Violation from Gamma-ray Burst Polarization
NASA Technical Reports Server (NTRS)
Stecker, Floyd W.
2011-01-01
Constraints on possible Lorentz invariance violation (UV) to first order in E/M(sub Plank) for photons in the framework of effective field theory (EFT) are discussed, taking cosmological factors into account. Then. using the reported detection of polarized soft gamma-ray emission from the gamma-ray burst GRB041219a that is indicative' of an absence of vacuum birefringence, together with a very recent improved method for estimating the redshift of the burst, we derive constraints on the dimension 5 Lorentz violating modification to the Lagrangian of an effective local QFT for QED. Our new constraints are more than five orders of magnitude better than recent constraints from observations of the Crab Nebula.. We obtain the upper limit on the Lorentz violating dimension 5 EFT parameter absolute value of zeta of 2.4 x 10(exp -15), corresponding to a constraint on the dimension 5 standard model extension parameter. Kappa (sup 5) (sub (v)oo) much less than 4.2 X 10(exp -3)4 / GeV.
Michelson-Morley analogue for electrons using trapped ions to test Lorentz symmetry
NASA Astrophysics Data System (ADS)
Pruttivarasin, T.; Ramm, M.; Porsev, S. G.; Tupitsyn, I. I.; Safronova, M. S.; Hohensee, M. A.; Häffner, H.
2015-01-01
All evidence so far suggests that the absolute spatial orientation of an experiment never affects its outcome. This is reflected in the standard model of particle physics by requiring all particles and fields to be invariant under Lorentz transformations. The best-known tests of this important cornerstone of physics are Michelson-Morley-type experiments verifying the isotropy of the speed of light. For matter, Hughes-Drever-type experiments test whether the kinetic energy of particles is independent of the direction of their velocity, that is, whether their dispersion relations are isotropic. To provide more guidance for physics beyond the standard model, refined experimental verifications of Lorentz symmetry are desirable. Here we search for violation of Lorentz symmetry for electrons by performing an electronic analogue of a Michelson-Morley experiment. We split an electron wave packet bound inside a calcium ion into two parts with different orientations and recombine them after a time evolution of 95 milliseconds. As the Earth rotates, the absolute spatial orientation of the two parts of the wave packet changes, and anisotropies in the electron dispersion will modify the phase of the interference signal. To remove noise, we prepare a pair of calcium ions in a superposition of two decoherence-free states, thereby rejecting magnetic field fluctuations common to both ions. After a 23-hour measurement, we find a limit of h × 11 millihertz (h is Planck's constant) on the energy variations, verifying the isotropy of the electron's dispersion relation at the level of one part in 1018, a 100-fold improvement on previous work. Alternatively, we can interpret our result as testing the rotational invariance of the Coulomb potential. Assuming that Lorentz symmetry holds for electrons and that the photon dispersion relation governs the Coulomb force, we obtain a fivefold-improved limit on anisotropies in the speed of light. Our result probes Lorentz symmetry violation at
Michelson-Morley analogue for electrons using trapped ions to test Lorentz symmetry.
Pruttivarasin, T; Ramm, M; Porsev, S G; Tupitsyn, I I; Safronova, M S; Hohensee, M A; Häffner, H
2015-01-29
All evidence so far suggests that the absolute spatial orientation of an experiment never affects its outcome. This is reflected in the standard model of particle physics by requiring all particles and fields to be invariant under Lorentz transformations. The best-known tests of this important cornerstone of physics are Michelson-Morley-type experiments verifying the isotropy of the speed of light. For matter, Hughes-Drever-type experiments test whether the kinetic energy of particles is independent of the direction of their velocity, that is, whether their dispersion relations are isotropic. To provide more guidance for physics beyond the standard model, refined experimental verifications of Lorentz symmetry are desirable. Here we search for violation of Lorentz symmetry for electrons by performing an electronic analogue of a Michelson-Morley experiment. We split an electron wave packet bound inside a calcium ion into two parts with different orientations and recombine them after a time evolution of 95 milliseconds. As the Earth rotates, the absolute spatial orientation of the two parts of the wave packet changes, and anisotropies in the electron dispersion will modify the phase of the interference signal. To remove noise, we prepare a pair of calcium ions in a superposition of two decoherence-free states, thereby rejecting magnetic field fluctuations common to both ions. After a 23-hour measurement, we find a limit of h × 11 millihertz (h is Planck's constant) on the energy variations, verifying the isotropy of the electron's dispersion relation at the level of one part in 10(18), a 100-fold improvement on previous work. Alternatively, we can interpret our result as testing the rotational invariance of the Coulomb potential. Assuming that Lorentz symmetry holds for electrons and that the photon dispersion relation governs the Coulomb force, we obtain a fivefold-improved limit on anisotropies in the speed of light. Our result probes Lorentz symmetry violation
Conformal differential invariants
NASA Astrophysics Data System (ADS)
Kruglikov, Boris
2017-03-01
We compute the Hilbert polynomial and the Poincaré function counting the number of fixed jet-order differential invariants of conformal metric structures modulo local diffeomorphisms, and we describe the field of rational differential invariants separating generic orbits of the diffeomorphism pseudogroup action. This resolves the local recognition problem for conformal structures.
Lorentz force megahertz optical coherence elastography
NASA Astrophysics Data System (ADS)
Wu, Chen; Singh, Manmohan; Han, Zhaolong; Raghunathan, Raksha; Liu, Chih-Hao; Li, Jiasong; Schill, Alexander; Larin, Kirill V.
2016-03-01
Optical Coherence Elastography (OCE) is a rapidly developing technique for assessing tissue biomechanical properties. This study demonstrates the first use of the Lorentz force to induce elastic waves within tissue to quantify the elasticity of tissue in combination with a phase-sensitive OCE system at ~1.5 million A-scans per second. The feasibility of this technique was tested on tissue-mimicking agar phantoms of various concentrations. The results as assessed by OCE were in good agreement with standard mechanical testing of the samples. After the preliminary experiments, the stiffness of porcine liver was examined. The results demonstrate that Lorentz force MHz OCE can be applied to study the elasticity of biological tissue effectively and has the potential for clinical applications due to rapid excitation and imaging.
Lorentz Symmetry as AN Emergent Phenomenon
NASA Astrophysics Data System (ADS)
Consoli, M.
2015-01-01
The vacuum of quantum gravity is believed to be a form of `space-time foam' which resembles a turbulent fluid. In this perspective, it is conceivable that Lorentz symmetry might be an emergent phenomenon. However, this idea of an underlying turbulent ether is not strictly peculiar of quantum gravity. This general picture suggests an alternative interpretation of the stochastic signal observed in the present ether-drift experiments with potentially important implications for both relativity and gravity.
The Lorentz anomaly via operator product expansion
Fredenhagen, Stefan; Hoppe, Jens Hynek, Mariusz
2015-10-15
The emergence of a critical dimension is one of the most striking features of string theory. One way to obtain it is by demanding closure of the Lorentz algebra in the light-cone gauge quantisation, as discovered for bosonic strings more than forty years ago. We give a detailed derivation of this classical result based on the operator product expansion on the Lorentzian world-sheet.
Mr. Tompkins in Java: Interactive Lorentz transformations
NASA Astrophysics Data System (ADS)
Saha, Prasenjit
2003-12-01
This paper describes a simple applet for illustrating Lorentz transformations. The user specifies stationary and moving objects and light pulses, and sees animations of two reference frames. Even with minimal graphics (the objects are colored dots and the light flashes are expanding circles), such animations can make the concepts of redshift, length contraction, time dilation, and non-simultaneity more intuitive than traditional spacetime diagrams.
Lorentz-Poincaré type aspects of the matter Lagrangian in General Relativity Theory
NASA Astrophysics Data System (ADS)
Broekaert, Jan B.
2007-04-01
It is well known that the solution to the Einstein Field Equation, gμν, can be either interpreted as the metric tensor itself or the mere gravitational field, their geochronometric correspondence being assured by the Equivalence Principle (e.g. Brown 2005). Within the field interpretation, which allows emphasis on physical effects of gravitation on microphysical constituents of matter, we expose gravitational Lorentz-Poincaré type properties of the relativistic gravitational matter Lagrangian. The Weierstrass parametrization (Johns 2005) of the matter Lagrangian LM in the explicit Lorentz-Poincaré type gravitation model is shown to render it equal to the standard matter Lagrangian —which can be reduced to the proper time invariant (gμνdxμ / dλdxν / dλ)1/2 for the geodesic motion (Stephani 2004)— in GRT. As such the GRT matter Lagrangian can be interpreted to result —following a Legendre transformation— from the energy of the matter fields obtained from Gravitationally Modified Lorentz Transformations (Broekaert 2005). The resultant correspondence between matter Lagrangians exposes explicitly the Lorentz-Poincaré type features such as (coordinate) spatially-variable speed of light, c(r) = c'Φ2, partial Machian mass induction m(r, ν) = m0'γΦ-3 and gravitational affecting of space and time observations in local coordinates in GRT. These features are only apparent relative to the coordinative manifold, while locally and in physical coordinates the effects all vanish in concordance with the local Minkowski metric.
Lorentz Atom Revisited by Solving the Abraham-Lorentz Equation of Motion
NASA Astrophysics Data System (ADS)
Bosse, Jürgen
2017-08-01
By solving the non-relativistic Abraham-Lorentz (AL) equation, I demonstrate that the AL equation of motion is not suited for treating the Lorentz atom, because a steady-state solution does not exist. The AL equation serves as a tool, however, for deducing the appropriate parameters Ω and Γ to be used with the equation of forced oscillations in modelling the Lorentz atom. The electric polarisability, which many authors "derived" from the AL equation in recent years, is shown to violate Kramers-Kronig relations rendering obsolete the extracted photon-absorption rate, for example. Fortunately, errors turn out to be small quantitatively, as long as the light frequency ω is neither too close to nor too far from the resonance frequency Ω. The polarisability and absorption cross section are derived for the Lorentz atom by purely classical reasoning and are shown to agree with the quantum mechanical calculations of the same quantities. In particular, oscillator parameters Ω and Γ deduced by treating the atom as a quantum oscillator are found to be equivalent to those derived from the classical AL equation. The instructive comparison provides a deep insight into understanding the great success of Lorentz's model that was suggested long before the advent of quantum theory.
Casimir effects in Lorentz-violating scalar field theory
NASA Astrophysics Data System (ADS)
Cruz, M. B.; de Mello, E. R. Bezerra; Petrov, A. Yu.
2017-08-01
In this paper, we consider a Lorentz-breaking extension of the theory for a real massive scalar quantum field in the region between two large parallel plates, with our manner to break the Lorentz symmetry being C P T even and aetherlike. For this system, we calculated the Casimir energy considering different boundary conditions. It turns out that the Casimir energy strongly depends on the direction of the constant vector implementing the Lorentz symmetry breaking as well as on the boundary conditions.
Lorentz violation in Bhabha scattering at finite temperature
NASA Astrophysics Data System (ADS)
Santos, A. F.; Khanna, Faqir C.
2017-06-01
Corrections to the Bhabha scattering cross section, due to Lorentz violation, at finite temperature are calculated. The vertex interaction between fermions and photons is modified by introducing the Lorentz violation, for the Standard Model extension, from C P T odd nonminimal coupling. The finite temperature corrections are calculated using the thermo field dynamics formalism. The Lorentz violation corrections are presented for zero to high temperatures.
Cosmological disformal invariance
Domènech, Guillem; Sasaki, Misao; Naruko, Atsushi E-mail: naruko@th.phys.titech.ac.jp
2015-10-01
The invariance of physical observables under disformal transformations is considered. It is known that conformal transformations leave physical observables invariant. However, whether it is true for disformal transformations is still an open question. In this paper, it is shown that a pure disformal transformation without any conformal factor is equivalent to rescaling the time coordinate. Since this rescaling applies equally to all the physical quantities, physics must be invariant under a disformal transformation, that is, neither causal structure, propagation speed nor any other property of the fields are affected by a disformal transformation itself. This fact is presented at the action level for gravitational and matter fields and it is illustrated with some examples of observable quantities. We also find the physical invariance for cosmological perturbations at linear and high orders in perturbation, extending previous studies. Finally, a comparison with Horndeski and beyond Horndeski theories under a disformal transformation is made.
Cosmological disformal invariance
NASA Astrophysics Data System (ADS)
Domènech, Guillem; Naruko, Atsushi; Sasaki, Misao
2015-10-01
The invariance of physical observables under disformal transformations is considered. It is known that conformal transformations leave physical observables invariant. However, whether it is true for disformal transformations is still an open question. In this paper, it is shown that a pure disformal transformation without any conformal factor is equivalent to rescaling the time coordinate. Since this rescaling applies equally to all the physical quantities, physics must be invariant under a disformal transformation, that is, neither causal structure, propagation speed nor any other property of the fields are affected by a disformal transformation itself. This fact is presented at the action level for gravitational and matter fields and it is illustrated with some examples of observable quantities. We also find the physical invariance for cosmological perturbations at linear and high orders in perturbation, extending previous studies. Finally, a comparison with Horndeski and beyond Horndeski theories under a disformal transformation is made.
Invariants of polarization transformations.
Sadjadi, Firooz A
2007-05-20
The use of polarization-sensitive sensors is being explored in a variety of applications. Polarization diversity has been shown to improve the performance of the automatic target detection and recognition in a significant way. However, it also brings out the problems associated with processing and storing more data and the problem of polarization distortion during transmission. We present a technique for extracting attributes that are invariant under polarization transformations. The polarimetric signatures are represented in terms of the components of the Stokes vectors. Invariant algebra is then used to extract a set of signature-related attributes that are invariant under linear transformation of the Stokes vectors. Experimental results using polarimetric infrared signatures of a number of manmade and natural objects undergoing systematic linear transformations support the invariancy of these attributes.
Far-field intensity of Lorentz related beams
NASA Astrophysics Data System (ADS)
Peng, Xi; Chen, Chidao; Chen, Bo; Peng, Yulian; Zhou, Meiling; Zhang, Liping; Li, Dongdong; Deng, Dongmei
2016-12-01
We introduce a sufficient condition under which the Lorentz beam convolution with other beams constitutes valid cross-spectral densities. Two examples are given to show how the Lorentz related beam can be used for generation of a far field being a modulated version of another one. The far-field intensity patterns in the Cartesian symmetries by the convolution operation of the Lorentz beams with multi-sinc beams, and the convolution operation of the Lorentz beams with multi-sinc Gaussian beams, are shown respectively. We find that different beam order can result distinct far field changes.
Fractional Fourier transform of Lorentz-Gauss beams.
Zhou, Guoquan
2009-02-01
Lorentz-Gauss beams are introduced to describe certain laser sources that produce highly divergent beams. The fractional Fourier transform (FRFT) is applied to treat the propagation of Lorentz-Gauss beams. Based on the definition of convolution and the convolution theorem of the Fourier transform, an analytical expression for a Lorentz-Gauss beam passing through an FRFT system has been derived. By using the derived expression, the properties of a Lorentz-Gauss beam in the FRFT plane are graphically illustrated with numerical examples.
Consistent Lorentz violation in flat and curved space
Dvali, Gia; Pujolas, Oriol; Redi, Michele
2007-08-15
Motivated by the severity of the bounds on Lorentz violation in the presence of ordinary gravity, we study frameworks in which Lorentz violation does not affect the spacetime geometry. We show that there are at least two inequivalent classes of spontaneous Lorentz breaking that even in the presence of gravity result in Minkowski space. The first one generically corresponds to the condensation of tensor fields with tachyonic mass, which in turn is related to ghost condensation. In the second class, realized by the Dvali-Gabadadze-Porrati model or theories of massive gravitons, spontaneous Lorentz breaking is induced by the expectation value of sources. The generalization to de Sitter space is also discussed.
Explicit Krawtchouk moment invariants for invariant image recognition
NASA Astrophysics Data System (ADS)
Xiao, Bin; Zhang, Yanhong; Li, Linping; Li, Weisheng; Wang, Guoyin
2016-03-01
The existing Krawtchouk moment invariants are derived by a linear combination of geometric moment invariants. This indirect method cannot achieve perfect performance in rotation, scale, and translation (RST) invariant image recognition since the derivation of these invariants are not built on Krawtchouk polynomials. A direct method to derive RST invariants from Krawtchouk moments, named explicit Krawtchouk moment invariants, is proposed. The proposed method drives Krawtchouk moment invariants by algebraically eliminating the distorted (i.e., rotated, scaled, and translated) factor contained in the Krawtchouk moments of distorted image. Experimental results show that, compared with the indirect methods, the proposed approach can significantly improve the performance in terms of recognition accuracy and noise robustness.
Gauge invariant gluon spin operator for spinless nonlinear wave solutions
NASA Astrophysics Data System (ADS)
Lee, Bum-Hoon; Kim, Youngman; Pak, D. G.; Tsukioka, Takuya; Zhang, P. M.
2017-04-01
We consider nonlinear wave type solutions with intrinsic mass scale parameter and zero spin in a pure SU(2) quantum chromodynamics (QCD). A new stationary solution which can be treated as a system of static Wu-Yang monopole dressed in off-diagonal gluon field is proposed. A remarkable feature of such a solution is that it possesses a finite energy density everywhere. All considered nonlinear wave type solutions have common features: presence of the mass scale parameter, nonvanishing projection of the color fields along the propagation direction and zero spin. The last property requires revision of the gauge invariant definition of the spin density operator which is supposed to produce spin one states for the massless vector gluon field. We construct a gauge invariant definition of the classical gluon spin density operator which is unique and Lorentz frame independent.
Optical finite representation of the Lorentz group
NASA Astrophysics Data System (ADS)
Rodríguez-Lara, B. M.; Guerrero, J.
2015-12-01
We present a class of photonic lattices with an underlying symmetry given by a finite-dimensional representation of the 2+1D Lorentz group. In order to construct such a finite-dimensional representation of a non-compact group, we have to design a $\\mathcal{PT}$-symmetric optical structure. Thus, the array of coupled waveguides may keep or break $\\mathcal{PT}$-symmetry, leading to a device that behaves like an oscillator or directional amplifier, respectively. We show that the so-called linear $\\mathcal{PT}$-symmetric dimer belongs to this class of photonic lattices.
Lorentz Invariance Violation: the Latest Fermi Results and the GRB-AGN Complementarity
NASA Technical Reports Server (NTRS)
Bolmont, J.; Vasileiou, V.; Jacholkowska, A.; Piron, F.; Couturier, C.; Granot, J.; Stecker, F. W.; Cohen-Tanugi, J.; Longo, F.
2013-01-01
Because they are bright and distant, Gamma-ray Bursts (GRBs) have been used for more than a decade to test propagation of photons and to constrain relevant Quantum Gravity (QG) models in which the velocity of photons in vacuum can depend on their energy. With its unprecedented sensitivity and energy coverage, the Fermi satellite has provided the most constraining results on the QG energy scale so far. In this talk, the latest results obtained from the analysis of four bright GRBs observed by the Large Area Telescope will be reviewed. These robust results, cross-checked using three different analysis techniques set the limit on QG energy scale at E(sub QG,1) greater than 7.6 times the Planck energy for linear dispersion and E(sub QG,2) greater than 1.3 x 10(exp 11) gigaelectron volts for quadratic dispersion (95% CL). After describing the data and the analysis techniques in use, results will be discussed and confronted to latest constraints obtained with Active Galactic Nuclei.
Search for Lorentz invariance and CPT violation with muon antineutrinos in the MINOS Near Detector
Adamson, P.; et al.
2012-02-01
We have searched for sidereal variations in the rate of antineutrino interactions in the MINOS Near Detector. Using antineutrinos produced by the NuMI beam, we find no statistically significant sidereal modulation in the rate. When this result is placed in the context of the Standard Model Extension theory we are able to place upper limits on the coefficients defining the theory. These limits are used in combination with the results from an earlier analysis of MINOS neutrino data to further constrain the coefficients.
Testing Lorentz Invariance by Comparing Light Propagation in Vacuum and Matter
NASA Astrophysics Data System (ADS)
Nagel, M.; Möhle, K.; Döringshoff, K.; Herrmann, S.; Senger, A.; Kovalchuk, E. V.; Peters, A.
2011-12-01
We present a Michelson-Morley type experiment for testing the isotropy of the speed of light in vacuum and matter. The experiment compares the resonance frequency of a monolithic optical sapphire resonator with the resonance frequency of an orthogonal evacuated optical cavity made of fused silica while the whole setup is rotated on an air bearing turntable once every 45 s. Preliminary results yield an upper limit for the anisotropy of the speed of light in matter (sapphire) of Δc/c < 4 × 10-15, limited by the frequency stability of the sapphire resonator operated at room temperature. Work to increase the measurement sensitivity by more than one order of magnitude by cooling down the sapphire resonator to liquid helium temperatures (LHe) is currently under way.
Testing Lorentz Symmetry with Lunar Laser Ranging
NASA Astrophysics Data System (ADS)
Bourgoin, A.; Hees, A.; Bouquillon, S.; Le Poncin-Lafitte, C.; Francou, G.; Angonin, M.-C.
2016-12-01
Lorentz symmetry violations can be parametrized by an effective field theory framework that contains both general relativity and the standard model of particle physics called the standard-model extension (SME). We present new constraints on pure gravity SME coefficients obtained by analyzing lunar laser ranging (LLR) observations. We use a new numerical lunar ephemeris computed in the SME framework and we perform a LLR data analysis using a set of 20 721 normal points covering the period of August, 1969 to December, 2013. We emphasize that linear combination of SME coefficients to which LLR data are sensitive and not the same as those fitted in previous postfit residuals analysis using LLR observations and based on theoretical grounds. We found no evidence for Lorentz violation at the level of 10-8 for s¯T X, 10-12 for s¯X Y and s¯X Z, 10-11 for s¯X X-s¯Y Y and s¯X X+s¯Y Y-2 s¯Z Z-4.5 s¯Y Z, and 10-9 for s¯T Y+0.43 s¯T Z. We improve previous constraints on SME coefficient by a factor up to 5 and 800 compared to postfit residuals analysis of respectively binary pulsars and LLR observations.
Testing Lorentz Symmetry with Lunar Laser Ranging.
Bourgoin, A; Hees, A; Bouquillon, S; Le Poncin-Lafitte, C; Francou, G; Angonin, M-C
2016-12-09
Lorentz symmetry violations can be parametrized by an effective field theory framework that contains both general relativity and the standard model of particle physics called the standard-model extension (SME). We present new constraints on pure gravity SME coefficients obtained by analyzing lunar laser ranging (LLR) observations. We use a new numerical lunar ephemeris computed in the SME framework and we perform a LLR data analysis using a set of 20 721 normal points covering the period of August, 1969 to December, 2013. We emphasize that linear combination of SME coefficients to which LLR data are sensitive and not the same as those fitted in previous postfit residuals analysis using LLR observations and based on theoretical grounds. We found no evidence for Lorentz violation at the level of 10^{-8} for s[over ¯]^{TX}, 10^{-12} for s[over ¯]^{XY} and s[over ¯]^{XZ}, 10^{-11} for s[over ¯]^{XX}-s[over ¯]^{YY} and s[over ¯]^{XX}+s[over ¯]^{YY}-2s[over ¯]^{ZZ}-4.5s[over ¯]^{YZ}, and 10^{-9} for s[over ¯]^{TY}+0.43s[over ¯]^{TZ}. We improve previous constraints on SME coefficient by a factor up to 5 and 800 compared to postfit residuals analysis of respectively binary pulsars and LLR observations.
NASA Astrophysics Data System (ADS)
Li, Youning; Han, Muxin; Grassl, Markus; Zeng, Bei
2017-06-01
Invariant tensors are states in the SU(2) tensor product representation that are invariant under SU(2) action. They play an important role in the study of loop quantum gravity. On the other hand, perfect tensors are highly entangled many-body quantum states with local density matrices maximally mixed. Recently, the notion of perfect tensors has attracted a lot of attention in the fields of quantum information theory, condensed matter theory, and quantum gravity. In this work, we introduce the concept of an invariant perfect tensor (IPT), which is an n-valent tensor that is both invariant and perfect. We discuss the existence and construction of IPTs. For bivalent tensors, the IPT is the unique singlet state for each local dimension. The trivalent IPT also exists and is uniquely given by Wigner’s 3j symbol. However, we show that, surprisingly, 4-valent IPTs do not exist for any identical local dimension d. On the contrary, when the dimension is large, almost all invariant tensors are asymptotically perfect, which is a consequence of the phenomenon of the concentration of measure for multipartite quantum states.
Lorentz and CPT Tests with Spin-Polarized Solids
Bluhm, Robert; Kostelecky, V. Alan
2000-02-14
Experiments using macroscopic samples of spin-polarized matter offer exceptional sensitivity to Lorentz and CPT violation in the electron sector. Data from existing experiments with a spin-polarized torsion pendulum provide sensitivity in this sector rivaling that of all other existing experiments and could reveal spontaneous violation of Lorentz symmetry at the Planck scale. (c) 2000 The American Physical Society.
Lorentz and CPT tests with spin-polarized solids
Bluhm; Kostelecky
2000-02-14
Experiments using macroscopic samples of spin-polarized matter offer exceptional sensitivity to Lorentz and CPT violation in the electron sector. Data from existing experiments with a spin-polarized torsion pendulum provide sensitivity in this sector rivaling that of all other existing experiments and could reveal spontaneous violation of Lorentz symmetry at the Planck scale.
Lorentz Detuning of Superconducting Cavities with Unbalanced Field Profiles
Delayen, Jean
2003-05-12
Tests on the prototype SNS medium beta cryomodule showed a strong correlation between the flatness of the field profile and the Lorentz detuning coefficient (both static and dynamic). We present an analytical model for the enhancement of the Lorentz detuning as a function of the flatness of the field profile resulting from a spread of the frequencies of the individual cells of the cavity.
Supersymmetric Lorentz Chern-Simons terms coupled to supergravity
Nishino, Hitoshi; Rajpoot, Subhash
2010-04-15
We present supersymmetric Lorentz Chern-Simons terms coupled to anti-de Sitter supergravity in three dimensions with an arbitrary number of supersymmetries. As an application to higher dimensions, we present analogous supersymmetric Lorentz Chern-Simons terms coupled to N=1 supergravity in 11 dimensions.
Chiral scale and conformal invariance in 2D quantum field theory.
Hofman, Diego M; Strominger, Andrew
2011-10-14
It is well known that a local, unitary Poincaré-invariant 2D quantum field theory with a global scaling symmetry and a discrete non-negative spectrum of scaling dimensions necessarily has both a left and a right local conformal symmetry. In this Letter, we consider a chiral situation beginning with only a left global scaling symmetry and do not assume Lorentz invariance. We find that a left conformal symmetry is still implied, while right translations are enhanced either to a right conformal symmetry or a left U(1) Kac-Moody symmetry.
Chiral Scale and Conformal Invariance in 2D Quantum Field Theory
NASA Astrophysics Data System (ADS)
Hofman, Diego M.; Strominger, Andrew
2011-10-01
It is well known that a local, unitary Poincaré-invariant 2D quantum field theory with a global scaling symmetry and a discrete non-negative spectrum of scaling dimensions necessarily has both a left and a right local conformal symmetry. In this Letter, we consider a chiral situation beginning with only a left global scaling symmetry and do not assume Lorentz invariance. We find that a left conformal symmetry is still implied, while right translations are enhanced either to a right conformal symmetry or a left U(1) Kac-Moody symmetry.
Effect of VSR invariant Chern-Simons Lagrangian on photon polarization
Nayak, Alekha C.; Verma, Ravindra K.; Jain, Pankaj E-mail: ravindkv@iitk.ac.in
2015-07-01
We propose a generalization of the Chern-Simons (CS) Lagrangian which is invariant under the SIM(2) transformations but not under the full Lorentz group. The generalized lagrangian is also invariant under a SIM(2) gauge transformation. We study the effect of such a term on radiation propagating over cosmological distances. We find that the dominant effect of this term is to produce circular polarization as radiation propagates through space. We use the circular polarization data from distant radio sources in order to impose a limit on this term.
Effect of VSR invariant Chern-Simons Lagrangian on photon polarization
NASA Astrophysics Data System (ADS)
Nayak, Alekha C.; Verma, Ravindra K.; Jain, Pankaj
2015-07-01
We propose a generalization of the Chern-Simons (CS) Lagrangian which is invariant under the SIM(2) transformations but not under the full Lorentz group. The generalized lagrangian is also invariant under a SIM(2) gauge transformation. We study the effect of such a term on radiation propagating over cosmological distances. We find that the dominant effect of this term is to produce circular polarization as radiation propagates through space. We use the circular polarization data from distant radio sources in order to impose a limit on this term.
Effect of VSR invariant Chern-Simons Lagrangian on photon polarization
Nayak, Alekha C.; Verma, Ravindra K.; Jain, Pankaj
2015-07-21
We propose a generalization of the Chern-Simons (CS) Lagrangian which is invariant under the SIM(2) transformations but not under the full Lorentz group. The generalized lagrangian is also invariant under a SIM(2) gauge transformation. We study the effect of such a term on radiation propagating over cosmological distances. We find that the dominant effect of this term is to produce circular polarization as radiation propagates through space. We use the circular polarization data from distant radio sources in order to impose a limit on this term.
ERIC Educational Resources Information Center
Kim, Y. S.; And Others
1979-01-01
Using covarient harmonic oscillator formalism as an illustrative example, a method is proposed for illustrating the difference between the Poincare (inhomogeneous Lorentz) and homogeneous Lorentz groups. (BT)
ERIC Educational Resources Information Center
Kim, Y. S.; And Others
1979-01-01
Using covarient harmonic oscillator formalism as an illustrative example, a method is proposed for illustrating the difference between the Poincare (inhomogeneous Lorentz) and homogeneous Lorentz groups. (BT)
Funabashi, Masatoshi
2015-05-01
This study applies information geometry of normal distribution to model Japanese vowels on the basis of the first and second formants. The distribution of Kullback-Leibler (KL) divergence and its decomposed components were investigated to reveal the statistical invariance in the vowel system. The results suggest that although significant variability exists in individual KL divergence distributions, the population distribution tends to converge into a specific log-normal distribution. This distribution can be considered as an invariant distribution for the standard-Japanese speaking population. Furthermore, it was revealed that the mean and variance components of KL divergence are linearly related in the population distribution. The significance of these invariant features is discussed.
Janse Van Rensburg, E.J.
1996-12-31
The geometry of polygonal knots in the cubic lattice may be used to define some knot invariants. One such invariant is the minimal edge number, which is the minimum number of edges necessary (and sufficient) to construct a lattice knot of given type. In addition, one may also define the minimal (unfolded) surface number, and the minimal (unfolded) boundary number; these are the minimum number of 2-cells necessary to construct an unfolded lattice Seifert surface of a given knot type in the lattice, and the minimum number of edges necessary in a lattice knot to guarantee the existence of an unfolded lattice Seifert surface. In addition, I derive some relations amongst these invariants. 8 refs., 5 figs., 2 tabs.
Generalized scale invariant theories
NASA Astrophysics Data System (ADS)
Padilla, Antonio; Stefanyszyn, David; Tsoukalas, Minas
2014-03-01
We present the most general actions of a single scalar field and two scalar fields coupled to gravity, consistent with second-order field equations in four dimensions, possessing local scale invariance. We apply two different methods to arrive at our results. One method, Ricci gauging, was known to the literature and we find this to produce the same result for the case of one scalar field as a more efficient method presented here. However, we also find our more efficient method to be much more general when we consider two scalar fields. Locally scale invariant actions are also presented for theories with more than two scalar fields coupled to gravity and we explain how one could construct the most general actions for any number of scalar fields. Our generalized scale invariant actions have obvious applications to early Universe cosmology and include, for example, the Bezrukov-Shaposhnikov action as a subset.
Supersymmetric invariant theories
NASA Astrophysics Data System (ADS)
Esipova, S. R.; Lavrov, P. M.; Radchenko, O. V.
2014-04-01
We study field models for which a quantum action (i.e. the action appearing in the generating functional of Green functions) is invariant under supersymmetric transformations. We derive the Ward identity which is a direct consequence of this invariance. We consider a change of variables in functional integral connected with supersymmetric transformations when its parameter is replaced by a nilpotent functional of fields. Exact form of the corresponding Jacobian is found. We find restrictions on generators of supersymmetric transformations when a consistent quantum description of given field theories exists.
Pokhozhaev, Stanislav I
2011-06-30
The notion of Riemann quasi-invariants is introduced and their applications to several conservation laws are considered. The case of nonisentropic flow of an ideal polytropic gas is analysed in detail. Sufficient conditions for gradient catastrophes are obtained. Bibliography: 16 titles.
Kobayashi, Tatsuo; Nitta, Daisuke; Urakawa, Yuko
2016-08-08
Modular invariance is a striking symmetry in string theory, which may keep stringy corrections under control. In this paper, we investigate a phenomenological consequence of the modular invariance, assuming that this symmetry is preserved as well as in a four dimensional (4D) low energy effective field theory. As a concrete setup, we consider a modulus field T whose contribution in the 4D effective field theory remains invariant under the modular transformation and study inflation drived by T. The modular invariance restricts a possible form of the scalar potenntial. As a result, large field models of inflation are hardly realized. Meanwhile, a small field model of inflation can be still accomodated in this restricted setup. The scalar potential traced during the slow-roll inflation mimics the hilltop potential V{sub ht}, but it also has a non-negligible deviation from V{sub ht}. Detecting the primordial gravitational waves predicted in this model is rather challenging. Yet, we argue that it may be still possible to falsify this model by combining the information in the reheating process which can be determined self-completely in this setup.
Modular invariant gaugino condensation
Gaillard, M.K.
1991-05-09
The construction of effective supergravity lagrangians for gaugino condensation is reviewed and recent results are presented that are consistent with modular invariance and yield a positive definite potential of the noscale type. Possible implications for phenomenology are briefly discussed. 29 refs.
NASA Astrophysics Data System (ADS)
Kobayashi, Tatsuo; Nitta, Daisuke; Urakawa, Yuko
2016-08-01
Modular invariance is a striking symmetry in string theory, which may keep stringy corrections under control. In this paper, we investigate a phenomenological consequence of the modular invariance, assuming that this symmetry is preserved as well as in a four dimensional (4D) low energy effective field theory. As a concrete setup, we consider a modulus field T whose contribution in the 4D effective field theory remains invariant under the modular transformation and study inflation drived by T. The modular invariance restricts a possible form of the scalar potenntial. As a result, large field models of inflation are hardly realized. Meanwhile, a small field model of inflation can be still accomodated in this restricted setup. The scalar potential traced during the slow-roll inflation mimics the hilltop potential Vht, but it also has a non-negligible deviation from Vht. Detecting the primordial gravitational waves predicted in this model is rather challenging. Yet, we argue that it may be still possible to falsify this model by combining the information in the reheating process which can be determined self-completely in this setup.
2004-05-01
change under the various nui- sances of image formation and viewing geometry was appealing; it held potential for application to recognition...Springer, 1990. 29. S. Z. Li. Shape matching based on invariants. In O. M. Omidvar (ed.), editor, Progress in Neural Networks : Shape Recognition, volume 6
Idiographic Measurement Invariance?
ERIC Educational Resources Information Center
Willoughby, Michael T.; Sideris, John
2007-01-01
In this article, the authors comment on Nesselroade, Gerstorf, Hardy, and Ram's efforts (this issue) to grapple with the challenge of accommodating idiographic assessment as it pertains to measurement invariance (MI). Although the authors are in complete agreement with the motivation for Nesselroade et al.'s work, the authors have concerns about…
Cheng, Miranda C. N.; Duncan, John F. R.; Harrison, Sarah M.; Kachru, Shamit
2017-01-01
In this note, we describe a connection between the enumerative geometry of curves in K3 surfaces and the chiral ring of an auxiliary superconformal field theory. We consider the invariants calculated by Yau–Zaslow (capturing the Euler characters of the moduli spaces of D2-branes on curves of given genus), together with their refinements to carry additional quantum numbers by Katz–Klemm–Vafa (KKV), and Katz–Klemm–Pandharipande (KKP). We show that these invariants can be reproduced by studying the Ramond ground states of an auxiliary chiral superconformal field theory which has recently been observed to give rise to mock modular moonshine for a variety of sporadic simple groups that are subgroups of Conway’s group. We also study equivariant versions of these invariants. A K3 sigma model is specified by a choice of 4-plane in the K3 D-brane charge lattice. Symmetries of K3 sigma models are naturally identified with 4-plane preserving subgroups of the Conway group, according to the work of Gaberdiel–Hohenegger–Volpato, and one may consider corresponding equivariant refined K3 Gopakumar–Vafa invariants. The same symmetries naturally arise in the auxiliary CFT state space, affording a suggestive alternative view of the same computation. We comment on a lift of this story to the generating function of elliptic genera of symmetric products of K3 surfaces.
Cheng, Miranda C. N.; Duncan, John F. R.; Harrison, Sarah M.; ...
2017-01-01
In this note, we describe a connection between the enumerative geometry of curves in K3 surfaces and the chiral ring of an auxiliary superconformal field theory. We consider the invariants calculated by Yau–Zaslow (capturing the Euler characters of the moduli spaces of D2-branes on curves of given genus), together with their refinements to carry additional quantum numbers by Katz–Klemm–Vafa (KKV), and Katz–Klemm–Pandharipande (KKP). We show that these invariants can be reproduced by studying the Ramond ground states of an auxiliary chiral superconformal field theory which has recently been observed to give rise to mock modular moonshine for a variety ofmore » sporadic simple groups that are subgroups of Conway’s group. We also study equivariant versions of these invariants. A K3 sigma model is specified by a choice of 4-plane in the K3 D-brane charge lattice. Symmetries of K3 sigma models are naturally identified with 4-plane preserving subgroups of the Conway group, according to the work of Gaberdiel–Hohenegger–Volpato, and one may consider corresponding equivariant refined K3 Gopakumar–Vafa invariants. The same symmetries naturally arise in the auxiliary CFT state space, affording a suggestive alternative view of the same computation. We comment on a lift of this story to the generating function of elliptic genera of symmetric products of K3 surfaces.« less
On asymptotic flatness and Lorentz charges
NASA Astrophysics Data System (ADS)
Compère, Geoffrey; Dehouck, François; Virmani, Amitabh
2011-07-01
In this paper we establish two results concerning four-dimensional asymptotically flat spacetimes at spatial infinity. First, we show that the six conserved Lorentz charges are encoded in two unique, distinct, but mutually dual symmetric divergence-free tensors that we construct from the equations of motion. Second, we show that the integrability of Einstein's equations in the asymptotic expansion is sufficient to establish the equivalence between counter-term charges defined from the variational principle and charges defined by Ashtekar and Hansen. These results clarify earlier constructions of conserved charges in the hyperboloid representation of spatial infinity. In showing this, the parity condition on the mass aspect is not needed. Along the way in establishing these results, we prove two lemmas on tensor fields on three-dimensional de Sitter spacetime stated by Ashtekar-Hansen and Beig-Schmidt and state and prove three additional lemmas. A la mémoire de notre ami et professeur Laurent Houart.
Dynamical properties of the Lorentz gas
NASA Astrophysics Data System (ADS)
Sharma, K. C.; Ranganathan, S.; Egelstaff, P. A.; Soper, A. K.
1987-07-01
A Lorentz gas interacting with a Lennard-Jones (LJ) potential and obeying classical equations of motion has been simulated by the molecular-dynamics method. A system of 255 Ar particles and one H2 molecule at a reduced Ar density 0.413 and temperature 2.475 is simplified by allowing the ``argon'' to have infinite mass, and the hydrogen molecule interacts with Ar atoms via the LJ potential. The simulated incoherent dynamic structure factor Ss(Q,ω) for the hydrogen molecule, which is corrected for the rotational states, is found to be in reasonable agreement with the experimental data of Egelstaff et al. (unpublished). One-parameter phenomenological model calculations are also compared to these data.
Testing Lorentz symmetry with planetary orbital dynamics
NASA Astrophysics Data System (ADS)
Hees, A.; Bailey, Q. G.; Le Poncin-Lafitte, C.; Bourgoin, A.; Rivoldini, A.; Lamine, B.; Meynadier, F.; Guerlin, C.; Wolf, P.
2015-09-01
Planetary ephemerides are a very powerful tool to constrain deviations from the theory of general relativity (GR) using orbital dynamics. The effective field theory framework called the Standard-Model Extension (SME) has been developed in order to systematically parametrize hypothetical violations of Lorentz symmetry (in the Standard Model and in the gravitational sector). In this communication, we use the latest determinations of the supplementary advances of the perihelia and of the nodes obtained by planetary ephemerides analysis to constrain SME coefficients from the pure gravity sector and also from gravity-matter couplings. Our results do not show any deviation from GR and they improve current constraints. Moreover, combinations with existing constraints from Lunar Laser Ranging and from atom interferometry gravimetry allow us to disentangle contributions from the pure gravity sector from the gravity-matter couplings.
NASA Astrophysics Data System (ADS)
Chamseddine, Riad
2016-04-01
A new vectorial representation for the successive Lorentz transformations (SLT) has recently been proved very convenient to achieve a straightforward treatment of the Thomas rotation effect. Such a representation rests on equivalent forms for the pure Lorentz transformation (PLT) and SLT whose physical meaning escaped us. The present paper fills this gap in by showing that those equivalent forms could represent appropriate world lines, lines and planes of simultaneity. Those geometric elements are particularly convenient to build up two new graphical representations for the SLT: the first rests on that equivalent form for the SLT, while the second takes the SLT as a PLT preceded or followed by a Thomas rotation and uses the equivalent form for the PLT. As an application, the SLT Lorentz contraction (SLTLC) formulas are derived for the first time. The dependence of the SLTLC on the Thomas rotation is put in evidence. The SLTLC along directions transverse and parallel to the composite velocity is studied. Original SLT Minkowski diagrams are given for the first time.
Unitary Representations of the Inhomogeneous Lorentz Group and Their Significance in Quantum Physics
NASA Astrophysics Data System (ADS)
Straumann, Norbert
Minkowski's great discovery of the spacetime structure behind Einstein's special theory of relativity (SR) had an enormous impact on much of twentieth-century physics. (For a historical account of Minkowski's Raum und Zeit lecture and Poincaré's pioneering contribution, we refer to [1] and Chap. 2, 10.1007/978-3-642-41992-8_2.) The symmetry requirement of physical theories with respect to the automorphism group of Minkowski spacetime - the inhomogeneous Lorentz or Poincaré group - is particularly constraining in the domain of relativistic quantum theory and led to profound insights. Among the most outstanding early contributions are Wigner's great papers on relativistic invariance [2]. His description of the (projective) irreducible representations of the inhomogeneous Lorentz group, that classified single particle states in terms of mass and spin, has later been taken up on the mathematical side by George Mackey, who developed Wigner's ideas into a powerful theory with a variety of important applications [3] [4] [5]. Mackey`s theory of induced representations has become an important part of representation theory for locally compact groups. For certain classes it provides a full description of all irreducible unitary representations.
Reconcile Planck-scale discreteness and the Lorentz-Fitzgerald contraction
NASA Astrophysics Data System (ADS)
Rovelli, Carlo; Speziale, Simone
2003-03-01
A Planck-scale minimal observable length appears in many approaches to quantum gravity. It is sometimes argued that this minimal length might conflict with Lorentz invariance, because a boosted observer can see the minimal length further Lorentz contracted. We show that this is not the case within loop quantum gravity. In loop quantum gravity the minimal length (more precisely, minimal area) does not appear as a fixed property of geometry, but rather as the minimal (nonzero) eigenvalue of a quantum observable. The boosted observer can see the same observable spectrum, with the same minimal area. What changes continuously in the boost transformation is not the value of the minimal length: it is the probability distribution of seeing one or the other of the discrete eigenvalues of the area. We discuss several difficulties associated with boosts and area measurement in quantum gravity. We compute the transformation of the area operator under a local boost, propose an explicit expression for the generator of local boosts, and give the conditions under which its action is unitary.
GZK photon constraints on Planck-scale Lorentz violation in QED
Maccione, Luca; Liberati, Stefano E-mail: liberati@sissa.it
2008-08-15
We show how the argument exploited by Galaverni and Sigl (2008 Phys. Rev. Lett. 100 021102 (see also 0708.1737)) to constrain Lorentz invariance violation (LV) using ultra-high-energy photon non-observation by the AUGER experiment can be extended to QED with Planck-suppressed LV (at O(E/M) and O(E{sup 2}/M{sup 2})). While the original constraints given by Galaverni and Sigl (2008 Phys. Rev. Lett. 100 021102) happen to be weakened, we show that, when used together with other EFT reactions and the expected detection of photons at E>10{sup 19} eV by AUGER, this method has the potentiality not only to basically rule out O(E/M) corrections but also to strongly constrain, for the first time, the CPT even O(E{sup 2}/M{sup 2}) LV QED.
Measurement Invariance versus Selection Invariance: Is Fair Selection Possible?
ERIC Educational Resources Information Center
Borsman, Denny; Romeijn, Jan-Willem; Wicherts, Jelte M.
2008-01-01
This article shows that measurement invariance (defined in terms of an invariant measurement model in different groups) is generally inconsistent with selection invariance (defined in terms of equal sensitivity and specificity across groups). In particular, when a unidimensional measurement instrument is used and group differences are present in…
Measurement Invariance versus Selection Invariance: Is Fair Selection Possible?
ERIC Educational Resources Information Center
Borsman, Denny; Romeijn, Jan-Willem; Wicherts, Jelte M.
2008-01-01
This article shows that measurement invariance (defined in terms of an invariant measurement model in different groups) is generally inconsistent with selection invariance (defined in terms of equal sensitivity and specificity across groups). In particular, when a unidimensional measurement instrument is used and group differences are present in…
Markov invariants, plethysms, and phylogenetics.
Sumner, J G; Charleston, M A; Jermiin, L S; Jarvis, P D
2008-08-07
We explore model-based techniques of phylogenetic tree inference exercising Markov invariants. Markov invariants are group invariant polynomials and are distinct from what is known in the literature as phylogenetic invariants, although we establish a commonality in some special cases. We show that the simplest Markov invariant forms the foundation of the Log-Det distance measure. We take as our primary tool group representation theory, and show that it provides a general framework for analyzing Markov processes on trees. From this algebraic perspective, the inherent symmetries of these processes become apparent, and focusing on plethysms, we are able to define Markov invariants and give existence proofs. We give an explicit technique for constructing the invariants, valid for any number of character states and taxa. For phylogenetic trees with three and four leaves, we demonstrate that the corresponding Markov invariants can be fruitfully exploited in applied phylogenetic studies.
Limits on Lorentz violation from synchrotron and inverse Compton sources.
Altschul, B
2006-05-26
We derive new bounds on Lorentz violations in the electron sector from existing data on high-energy astrophysical sources. Synchrotron and inverse Compton data give precisely complementary constraints. The best bound on a specific combination of electron Lorentz-violating coefficients is at the 6 x 10(-20) level, and independent bounds are available for all the Lorentz-violating c coefficients at the 2 x 10(-14)level or better. This represents an improvement in some bounds by 14 orders of magnitude.
Strong binary pulsar constraints on Lorentz violation in gravity.
Yagi, Kent; Blas, Diego; Yunes, Nicolás; Barausse, Enrico
2014-04-25
Binary pulsars are excellent laboratories to test the building blocks of Einstein's theory of general relativity. One of these is Lorentz symmetry, which states that physical phenomena appear the same for all inertially moving observers. We study the effect of violations of Lorentz symmetry in the orbital evolution of binary pulsars and find that it induces a much more rapid decay of the binary's orbital period due to the emission of dipolar radiation. The absence of such behavior in recent observations allows us to place the most stringent constraints on Lorentz violation in gravity, thus verifying one of the cornerstones of Einstein's theory much more accurately than any previous gravitational observation.
Ultrarelativistic Bose-Einstein gas on Lorentz symmetry violation
NASA Astrophysics Data System (ADS)
de Sales, J. A.; Costa-Soares, T.; Vasquez Otoya, V. J.
2012-11-01
In this paper, we study the effects of Lorentz Symmetry Breaking on the thermodynamic properties of ideal gases. Inspired by the dispersion relation coming from the Carroll-Field-Jackiw model for Electrodynamics with Lorentz and CPT violation term, we compute the thermodynamics quantities for a Boltzmann, Fermi-Dirac and Bose-Einstein distributions. Two regimes are analyzed: the large and the small Lorentz violation. In the first case, we show that the topological mass induced by the Chern-Simons term behaves as a chemical potential. For Bose-Einstein gases, a condensation in both regimes can be found.
Disentangling forms of Lorentz violation with complementary clock comparison experiments
Altschul, Brett
2009-03-15
Atomic clock comparisons provide some of the most precise tests of Lorentz and CPT symmetries in the laboratory. With data from multiple such experiments using different nuclei, it is possible to constrain new regions of the parameter space for Lorentz violation. Relativistic effects in the nuclei allow us to disentangle forms of Lorentz violation which could not be separately measured in purely nonrelativistic experiments. The disentangled bounds in the neutron sectors are at the 10{sup -28} GeV level, far better than could be obtained with any other current technique.
New inversion methods for the Lorentz Integral Transform
NASA Astrophysics Data System (ADS)
Andreasi, D.; Leidemann, W.; Reiß, C.; Schwamb, M.
2005-06-01
The Lorentz Integral Transform approach allows microscopic calculations of electromagnetic reaction cross-sections without explicit knowledge of final-state wave functions. The necessary inversion of the transform has to be treated with great care, since it constitutes a so-called ill-posed problem. In this work new inversion techniques for the Lorentz Integral Transform are introduced. It is shown that they all contain a regularization scheme, which is necessary to overcome the ill-posed problem. In addition, it is illustrated that the new techniques have a much broader range of application than the present standard inversion method of the Lorentz Integral Transform.
NASA Astrophysics Data System (ADS)
Arkani-Hamed, Nima; Cheng, Hsin-Chia; Luty, Markus; Thaler, Jesse
2005-07-01
We study the universal low-energy dynamics associated with the spontaneous breaking of Lorentz invariance down to spatial rotations. The effective lagrangian for the associated Goldstone field can be uniquely determined by the non-linear realization of a broken time diffeomorphism symmetry, up to some overall mass scales. It has previously been shown that this symmetry breaking pattern gives rise to a Higgs phase of gravity, in which gravity is modified in the infrared. In this paper, we study the effects of direct couplings between the Goldstone boson and standard model fermions, which necessarily accompany Lorentz-violating terms in the theory. The leading interaction is the coupling to the axial vector current, which reduces to spin in the non-relativistic limit. A spin moving relative to the ``ether" rest frame will emit Goldstone Cerenkov radiation. The Goldstone also induces a long-range inverse-square law force between spin sources with a striking angular dependence, reflecting the underlying Goldstone shockwaves and providing a smoking gun for this theory. We discuss the regime of validity of the effective theory describing these phenomena, and the possibility of probing Lorentz violations through Goldstone boson signals in a way that is complementary to direct tests in some regions of parameter space.
NASA Astrophysics Data System (ADS)
Vollmer, Gerhard
2010-10-01
Scientific knowledge should not only be true, it should be as objective as possible. It should refer to a reality independent of any subject. What can we use as a criterion of objectivity? Intersubjectivity (i.e., intersubjective understandability and intersubjective testability) is necessary, but not sufficient. Other criteria are: independence of reference system, independence of method, non-conventionality. Is there some common trait? Yes, there is: invariance under some specified transformations. Thus, we say: A proposition is objective only if its truth is invariant against a change in the conditions under which it was formulated. We give illustrations from geometry, perception, neurobiology, relativity theory, and quantum theory. Such an objectivist position has many advantages.
Magnetic monopoles, Galilean invariance, and Maxwell's equations
NASA Astrophysics Data System (ADS)
Crawford, Frank S.
1992-02-01
Maxwell's equations have space reserved for magnetic monopoles. Whether or not they exist in our part of the universe, monopoles provide a useful didactic tool to help us recognize relations among Maxwell's equations less easily apparent in the approach followed by many introductory textbooks, wherein Coulomb's law, Biot and Savart's law, Ampere's law, Faraday's law, Maxwell's displacement current, etc., are introduced independently, ``as demanded by experiment.'' Instead a conceptual path that deduces all of Maxwell's equations from the near-minimal set of assumptions: (a) Inertial frames exist, in which Newton's laws hold, to a first approximation; (b) the laws of electrodynamics are Galilean invariant-i.e., they have the same form in every inertial frame, to a first approximation; (c) magnetic poles (as well as the usual electric charges) exist; (d) the complete Lorentz force on an electric charge is known; (e) the force on a monopole at rest is known; (f) the Coulomb-like field produced by a resting electric charge and by a resting monopole are known. Everything else is deduced. History is followed in the assumption that Newtonian mechanics have been discovered, but not special relativity. (Only particle velocities v<
2010-12-02
evaluating the function ΘP (A) for any fixed A,P is equivalent to solving the so-called Quadratic Assignment Problem ( QAP ), and thus we can employ various...tractable linear programming, spectral, and SDP relaxations of QAP [40, 11, 33]. In particular we discuss recent work [14] on exploiting group...symmetry in SDP relaxations of QAP , which is useful for approximately computing elementary convex graph invariants in many interesting cases. Finally in
View Invariant Gait Recognition
NASA Astrophysics Data System (ADS)
Seely, Richard D.; Goffredo, Michela; Carter, John N.; Nixon, Mark S.
Recognition by gait is of particular interest since it is the biometric that is available at the lowest resolution, or when other biometrics are (intentionally) obscured. Gait as a biometric has now shown increasing recognition capability. There are many approaches and these show that recognition can achieve excellent performance on current large databases. The majority of these approaches are planar 2D, largely since the early large databases featured subjects walking in a plane normal to the camera view. To extend deployment capability, we need viewpoint invariant gait biometrics. We describe approaches where viewpoint invariance is achieved by 3D approaches or in 2D. In the first group, the identification relies on parameters extracted from the 3D body deformation during walking. These methods use several video cameras and the 3D reconstruction is achieved after a camera calibration process. On the other hand, the 2D gait biometric approaches use a single camera, usually positioned perpendicular to the subject’s walking direction. Because in real surveillance scenarios a system that operates in an unconstrained environment is necessary, many of the recent gait analysis approaches are orientated toward view-invariant gait recognition.
Measurement of Lorentz Angle for the CMS Pixel Detector
NASA Astrophysics Data System (ADS)
Kumar, Ashish
2010-02-01
At the core of the CMS all-silicon tracking system is the silicon pixel detector, comprising three barrel layers and two pixel disks in the forward and backward regions, accounting for a total of 66 million channels. The pixel detector will provide high-resolution 3D coordinates of the tracks produced in high energy pp collisions. Under the combined action of electric and magnetic fields, the charged carriers traversing the pixel sensors experience the Lorentz force. It causes charge sharing among neighboring pixels which is crucial in enhancing the spatial resolution. In the barrel pixels, the electric and magnetic fields are perpendicular resulting in maximum Lorentz drift, while, in the disks, the fields are oriented at 20 degrees resulting in much smaller Lorentz drift. We present the results of Lorentz angle measurement for the pixel detector using CMS data taken with cosmic runs. )
LORENTZ SELF-FORCE OF AN ELLIPSE CURRENT LOOP MODEL
Olmedo, Oscar; Zhang Jie; Kunkel, Valbona
2013-07-10
In this work, the Lorentz self-force of an ellipse current loop model is derived. We are motivated by the fact that it has been reported in the literature that coronal mass ejection morphology can resemble an ellipse in the field of view of coronagraph images. Deriving the Lorentz self-force using an ellipse geometry has the advantage of being able to be solved analytically, as opposed to other more complex geometries. The derived ellipse model is compared with the local curvature approximation, where the Lorentz self-force at the ellipse major/minor axis is compared with the Lorentz self-force of a torus with curvature equal to the local curvature at the ellipses major/minor axis. It is found that the local curvature approximation is valid for moderate values of eccentricity.
Vacuum photon splitting in Lorentz-violating quantum electrodynamics.
Kostelecký, V Alan; Pickering, Austin G M
2003-07-18
Radiative corrections arising from Lorentz violation in the fermion sector induce a nonzero amplitude for vacuum photon splitting. At one loop, the on-shell amplitude acquires both CPT-even and CPT-odd contributions forbidden in conventional electrodynamics.
Larmor and the Prehistory of the Lorentz Transformations
ERIC Educational Resources Information Center
Kittel, C.
1974-01-01
A historical analysis is given of the development in 1900 of the Lorentz transformation of coordinates and time, and of electric and magnetic field components. The earlier work of Voight is discussed. (RH)
Comment on ‘Lorentz transformations and the wave equation’
NASA Astrophysics Data System (ADS)
Di Rocco, Héctor O.
2017-01-01
In this comment we make some clarifications with respect to certain asumptions and demands required by Ricardo Heras in his paper entitled ‘Lorentz transformations and the wave equation’ (2016 Eur. J. Phys. 37 025603).
Traveling solitons in Lorentz and CPT breaking systems
Souza Dutra, A. de; Correa, R. A. C.
2011-05-15
In this work we present a class of traveling solitons in Lorentz and CPT breaking systems. In the case of Lorentz violating scenarios, as far as we know, only static solitonic configurations were analyzed up to now in the literature. Here it is shown that it is possible to construct some traveling solitons which cannot be mapped into static configurations by means of Lorentz boosts due to explicit breaking. In fact, the traveling solutions cannot be reached from the static ones by using something similar to a Lorentz boost in those cases. Furthermore, in the model studied, a complete set of exact solutions is obtained. The solutions present a critical behavior controlled by the choice of an arbitrary integration constant.
Relativistic quantum scattering yielded by Lorentz symmetry breaking effects
NASA Astrophysics Data System (ADS)
Mota, H. F.; Bakke, K.; Belich, H.
2017-08-01
We investigate the scattering of a relativistic scalar quantum particle induced by a scattering-like potential that arises from the effects of the violation of the Lorentz symmetry. We then obtain the scattering phase shift caused by the influence of such a potential and use it to calculate the exact expressions for the scattering amplitude as well as for the total scattering cross-section through the optical theorem. In addition, we estimate an upper bound for the Lorentz symmetry violation parameters.
Experimental calibration procedures for rotating Lorentz-force flowmeters
NASA Astrophysics Data System (ADS)
Hvasta, M. G.; Slighton, N. T.; Kolemen, E.; Fisher, A. E.
2017-08-01
Rotating Lorentz-force flowmeters are a novel and useful technology with a range of applications in a variety of different industries. However, calibrating these flowmeters can be challenging, time-consuming, and expensive. In this paper, simple calibration procedures for rotating Lorentz-force flowmeters are presented. These procedures eliminate the need for expensive equipment, numerical modeling, redundant flowmeters, and system down-time. The calibration processes are explained in a step-by-step manner and compared to experimental results.
Experimental calibration procedures for rotating Lorentz-force flowmeters
Hvasta, M. G.; Slighton, N. T.; Kolemen, E.; ...
2017-07-14
Rotating Lorentz-force flowmeters are a novel and useful technology with a range of applications in a variety of different industries. However, calibrating these flowmeters can be challenging, time-consuming, and expensive. In this paper, simple calibration procedures for rotating Lorentz-force flowmeters are presented. These procedures eliminate the need for expensive equipment, numerical modeling, redundant flowmeters, and system down-time. Finally, the calibration processes are explained in a step-by-step manner and compared to experimental results.
Lorentz-breaking theory with higher derivatives in spinor sector
NASA Astrophysics Data System (ADS)
Nascimento, J. R.; Petrov, A. Yu.; Reyes, C. Marat
2015-08-01
We consider the two-point function of the gauge field in Lorentz-breaking theories with higher-derivative extension of the Dirac Lagrangian. We show that the Carroll-Field-Jackiw term naturally arises in this theory as a quantum correction being perfectly finite and thus displaying no ambiguities. Also, the finiteness of this term at the low energy limit and the absence of large Lorentz violating corrections allows to avoid the fine-tuning problem.
Limits on neutron Lorentz violation from pulsar timing
Altschul, Brett
2007-01-15
Pulsars are the most accurate naturally occurring clocks, and data about them can be used to set bounds on neutron-sector Lorentz violations. If SO(3) rotation symmetry is completely broken for neutrons, then pulsars' rotation speeds will vary periodically. Pulsar timing data limits the relevant Lorentz-violating coefficients to be smaller than 1.7x10{sup -8} at at least 90% confidence.
Hendrik Antoon Lorentz: his role in physics and society.
Berends, Frits
2009-04-22
Hendrik Antoon Lorentz (1853-1928) was appointed in 1878 to a chair of theoretical physics at the University of Leiden, one of the first of such chairs in the world. A few years later Heike Kamerlingh Onnes became his experimental colleague, after vehement discussions in the faculty. Lorentz strongly supported Kamerlingh Onnes then, and proved subsequently to be an ideal colleague. With Lorentz's electron theory the classical theory of electromagnetism obtained its final form, at the time often called the Maxwell-Lorentz theory. In this theory the Zeeman effect could be explained: the first glimpse of the electron. The Nobel Prize followed in 1902. The Lorentz transformation, established in 1904, preceded the special theory of relativity. Later on, Lorentz played a much admired role in the debate on the new developments in physics, in particular as chairman of a series of Solvay conferences. Gradually his stature outside of physics grew, both nationally as chairman of the Zuiderzee committee and internationally as president of the International Commission on Intellectual Cooperation of the League of Nations. At his funeral the overwhelming tribute was the recognition of his unique greatness. Einstein said about him 'He meant more to me personally than anyone else I have met on my life's journey'.
Hendrik Antoon Lorentz: his role in physics and society
NASA Astrophysics Data System (ADS)
Berends, Frits
2009-04-01
Hendrik Antoon Lorentz (1853-1928) was appointed in 1878 to a chair of theoretical physics at the University of Leiden, one of the first of such chairs in the world. A few years later Heike Kamerlingh Onnes became his experimental colleague, after vehement discussions in the faculty. Lorentz strongly supported Kamerlingh Onnes then, and proved subsequently to be an ideal colleague. With Lorentz's electron theory the classical theory of electromagnetism obtained its final form, at the time often called the Maxwell-Lorentz theory. In this theory the Zeeman effect could be explained: the first glimpse of the electron. The Nobel Prize followed in 1902. The Lorentz transformation, established in 1904, preceded the special theory of relativity. Later on, Lorentz played a much admired role in the debate on the new developments in physics, in particular as chairman of a series of Solvay conferences. Gradually his stature outside of physics grew, both nationally as chairman of the Zuiderzee committee and internationally as president of the International Commission on Intellectual Cooperation of the League of Nations. At his funeral the overwhelming tribute was the recognition of his unique greatness. Einstein said about him 'He meant more to me personally than anyone else I have met on my life's journey'.
A new look at Lorentz-covariant loop quantum gravity
NASA Astrophysics Data System (ADS)
Geiller, Marc; Lachièze-Rey, Marc; Noui, Karim
2011-08-01
In this work, we study the classical and quantum properties of the unique commutative Lorentz-covariant connection for loop quantum gravity. This connection has been found after solving the second-class constraints inherited from the canonical analysis of the Holst action without the time gauge. We show that it has the property of lying in the conjugacy class of a pure su(2) connection, a result which enables one to construct the kinematical Hilbert space of the Lorentz-covariant theory in terms of the usual SU(2) spin-network states. Furthermore, we show that there is a unique Lorentz-covariant electric field, up to trivial and natural equivalence relations. The Lorentz-covariant electric field transforms under the adjoint action of the Lorentz group, and the associated Casimir operators are shown to be proportional to the area density. This gives a very interesting algebraic interpretation of the area. Finally, we show that the action of the surface operator on the Lorentz-covariant holonomies reproduces exactly the usual discrete SU(2) spectrum of time-gauge loop quantum gravity. In other words, the use of the time gauge does not introduce anomalies in the quantum theory.
Lorentz Force Based Satellite Attitude Control
NASA Astrophysics Data System (ADS)
Giri, Dipak Kumar; Sinha, Manoranjan
2016-07-01
Since the inception of attitude control of a satellite, various active and passive control strategies have been developed. These include using thrusters, momentum wheels, control moment gyros and magnetic torquers. In this present work, a new technique named Lorentz force based Coulombic actuators for the active control is proposed. This method uses electrostatic charged shells, which interact with the time varying earth's magnetic field to establish a full three axes control of the satellite. It is shown that the proposed actuation mechanism is similar to a satellite actuated by magnetic coils except that the resultant magnetic moment vanishes under two different conditions. The equation for the required charges on the the Coulomb shells attached to the satellite body axes is derived, which is in turn used to find the available control torque for actuating the satellite along the orbit. Stability of the proposed system for very high initial angular velocity and exponential stability about the origin are proved for a proportional-differential control input. Simulations are carried out to show the efficacy of the proposed system for the attitude control of the earth-pointing satellite.
Direct Lorentz force compensation flowmeter for electrolytes
NASA Astrophysics Data System (ADS)
Vasilyan, S.; Froehlich, Th.
2014-12-01
A simplified method of contactless Lorentz force (LF) measurements for flow meters on electrolytes is described and realized. Modification and comparative representation are discussed against recently well-developed methods. Based on the catapult effect, that current carrying conductor experiences a repulsive force in a magnetic field, we demonstrate force measurement method of LF velocimetry applications by commonly known "electromagnetic force" compensation principle. Measurement approach through zero point stability is considered to minimize mechanical influences and avoid gravimetric uncertainties. Here, the current carrying wires are static fixed in the vicinity of magnet system at zero point stable position, while occurring deflection of magnets by electrolyte flow is compensated by external applied current within wires. Measurements performed by developed servo-system which drives control loop by means of optical position sensor for simplified (i) single wire and (ii) coil-like extended compensation schemes. Guided by experiments on electrolyte flow, we demonstrate the applicability of adopted principle for conductivities ranging from 2 to 20 S/m. Further improvements are discussed in agreement with the parameters of demonstration setup, straightforward theory, and experimental results. We argue that this method is potentially suitable for: (a) applications with higher conductivity like molten metal (order of 106 S/m) assuming spatial configuration of setup and (b) for lower range of conductivity (below 1 S/m) while this is strongly subject to stiffness of system and noise mainly mechanical and thermal radiations.
Direct Lorentz force compensation flowmeter for electrolytes
Vasilyan, S. Froehlich, Th.
2014-12-01
A simplified method of contactless Lorentz force (LF) measurements for flow meters on electrolytes is described and realized. Modification and comparative representation are discussed against recently well-developed methods. Based on the catapult effect, that current carrying conductor experiences a repulsive force in a magnetic field, we demonstrate force measurement method of LF velocimetry applications by commonly known “electromagnetic force” compensation principle. Measurement approach through zero point stability is considered to minimize mechanical influences and avoid gravimetric uncertainties. Here, the current carrying wires are static fixed in the vicinity of magnet system at zero point stable position, while occurring deflection of magnets by electrolyte flow is compensated by external applied current within wires. Measurements performed by developed servo-system which drives control loop by means of optical position sensor for simplified (i) single wire and (ii) coil-like extended compensation schemes. Guided by experiments on electrolyte flow, we demonstrate the applicability of adopted principle for conductivities ranging from 2 to 20 S/m. Further improvements are discussed in agreement with the parameters of demonstration setup, straightforward theory, and experimental results. We argue that this method is potentially suitable for: (a) applications with higher conductivity like molten metal (order of 10{sup 6 }S/m) assuming spatial configuration of setup and (b) for lower range of conductivity (below 1 S/m) while this is strongly subject to stiffness of system and noise mainly mechanical and thermal radiations.
Lorentz symmetry and very long baseline interferometry
NASA Astrophysics Data System (ADS)
Le Poncin-Lafitte, C.; Hees, A.; Lambert, S.
2016-12-01
Lorentz symmetry violations can be described by an effective field theory framework that contains both general relativity and the Standard Model of particle physics called the Standard Model extension (SME). Recently, postfit analysis of Gravity Probe B and binary pulsars led to an upper limit at the 10-4 level on the time-time coefficient s¯T T of the pure-gravity sector of the minimal SME. In this work, we derive the observable of very long baseline interferometry (VLBI) in SME and then implement it into a real data analysis code of geodetic VLBI observations. Analyzing all available observations recorded since 1979, we compare estimates of s¯T T and errors obtained with various analysis schemes, including global estimations over several time spans, and with various Sun elongation cutoff angles, and by analysis of radio source coordinate time series. We obtain a constraint on s¯ T T=(-5 ±8 )×10-5 , directly fitted to the observations and improving by a factor of 5 previous postfit analysis estimates.
Breaking Lorentz reciprocity to overcome the time-bandwidth limit in physics and engineering.
Tsakmakidis, K L; Shen, L; Schulz, S A; Zheng, X; Upham, J; Deng, X; Altug, H; Vakakis, A F; Boyd, R W
2017-06-23
A century-old tenet in physics and engineering asserts that any type of system, having bandwidth Δω, can interact with a wave over only a constrained time period Δt inversely proportional to the bandwidth (Δt·Δω ~ 2π). This law severely limits the generic capabilities of all types of resonant and wave-guiding systems in photonics, cavity quantum electrodynamics and optomechanics, acoustics, continuum mechanics, and atomic and optical physics but is thought to be completely fundamental, arising from basic Fourier reciprocity. We propose that this "fundamental" limit can be overcome in systems where Lorentz reciprocity is broken. As a system becomes more asymmetric in its transport properties, the degree to which the limit can be surpassed becomes greater. By way of example, we theoretically demonstrate how, in an astutely designed magnetized semiconductor heterostructure, the above limit can be exceeded by orders of magnitude by using realistic material parameters. Our findings revise prevailing paradigms for linear, time-invariant resonant systems, challenging the doctrine that high-quality resonances must invariably be narrowband and providing the possibility of developing devices with unprecedentedly high time-bandwidth performance. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.
Breaking Lorentz reciprocity to overcome the time-bandwidth limit in physics and engineering
NASA Astrophysics Data System (ADS)
Tsakmakidis, K. L.; Shen, L.; Schulz, S. A.; Zheng, X.; Upham, J.; Deng, X.; Altug, H.; Vakakis, A. F.; Boyd, R. W.
2017-06-01
A century-old tenet in physics and engineering asserts that any type of system, having bandwidth Δω, can interact with a wave over only a constrained time period Δt inversely proportional to the bandwidth (Δt·Δω ~ 2π). This law severely limits the generic capabilities of all types of resonant and wave-guiding systems in photonics, cavity quantum electrodynamics and optomechanics, acoustics, continuum mechanics, and atomic and optical physics but is thought to be completely fundamental, arising from basic Fourier reciprocity. We propose that this “fundamental” limit can be overcome in systems where Lorentz reciprocity is broken. As a system becomes more asymmetric in its transport properties, the degree to which the limit can be surpassed becomes greater. By way of example, we theoretically demonstrate how, in an astutely designed magnetized semiconductor heterostructure, the above limit can be exceeded by orders of magnitude by using realistic material parameters. Our findings revise prevailing paradigms for linear, time-invariant resonant systems, challenging the doctrine that high-quality resonances must invariably be narrowband and providing the possibility of developing devices with unprecedentedly high time-bandwidth performance.
Lorentz, the Solvay Councils and the Physics Institute
NASA Astrophysics Data System (ADS)
Berends, Frits A.
2015-09-01
This paper describes the crucial role which Lorentz played in shaping and continuing the Solvay Councils and the Physics Institute. At the same time it will become clear that Lorentz* intensive involvement in these activities added significantly to his influence on, and recognition in, the international physics community. The first Solvay Council in 1911 was an initiative of the German physical chemist Walther Nernst. It was generously supported by the wealthy industrialist and philantropist Ernest Solvay. About five months before the Council*s start Nernst invited Lorentz to chair the meeting. That was no simple task in view of the fundamental problem of the quanta and the practical problem of communication in different languages. Lorentz*s way of presiding the conference impressed all participants. When, after the meeting, Solvay was willing to support research in the field, it was only natural to ask Lorentz for a plan. Within two months Lorentz provided Solvay with a draft which would serve as an outline for the statutes of an institute. The international Solvay Institute of Physics was founded on 1 May 1912. It would support research proposals in a specified field and would regularly organize Councils. An international scientific committee would decide on grants which could be requested from everywhere. Between the Institute*s beginnings and the outbreak of WWI, 97 requests were considered and 40 proposals - originating from 7 countries - were accepted. A second Council took place in 1913. Lorentz was given the possibility to spend considerable time on chairing the scientific committee when in 1912 his full time professorship in Leiden was changed into a part-time one. During WWI Lorentz maintained contacts with Solvay and with several of his foreign colleagues in the countries at war. He tried to remain objective, impartial and helpful, and did not lose hope that pre-war international scientific relations would eventually be re-established. After the war he
Perspective Projection Invariants,
1986-02-01
ORGANIZATION NAME ANC ADDRESS 10. PROGRAM ELEMENT. PROJECT. TASK Artificial Inteligence Laboratory AREA & WORK UNIT NUMBERSO 545 Technology Square dCambridge...AD-AI67 793 PERSPECTIVE PROJECTION INVARIANTS(U) MASSACHUSETTS INST 1/1~ OF TECH CAMBRIDGE ARTIFICIAL INTELLIGENCE LAB VERRI ET AL, FEB 86 AI-M-832...0R020I4 661 SEC R TVC PAGE fjSr .W IlIII UI A 8 gT@OFTNS21 07 1 MASSACHUSETTS INSTITUTE OF TECHNOLOGY ARTIFICIAL INTELLIGENCE LABORATORY and CENTER
Entanglement, Invariants, and Phylogenetics
NASA Astrophysics Data System (ADS)
Sumner, J. G.
2007-10-01
This thesis develops and expands upon known techniques of mathematical physics relevant to the analysis of the popular Markov model of phylogenetic trees required in biology to reconstruct the evolutionary relationships of taxonomic units from biomolecular sequence data. The techniques of mathematical physics are plethora and have been developed for some time. The Markov model of phylogenetics and its analysis is a relatively new technique where most progress to date has been achieved by using discrete mathematics. This thesis takes a group theoretical approach to the problem by beginning with a remarkable mathematical parallel to the process of scattering in particle physics. This is shown to equate to branching events in the evolutionary history of molecular units. The major technical result of this thesis is the derivation of existence proofs and computational techniques for calculating polynomial group invariant functions on a multi-linear space where the group action is that relevant to a Markovian time evolution. The practical results of this thesis are an extended analysis of the use of invariant functions in distance based methods and the presentation of a new reconstruction technique for quartet trees which is consistent with the most general Markov model of sequence evolution.
A Real Lorentz-FitzGerald Contraction
NASA Astrophysics Data System (ADS)
Barceló, Carlos; Jannes, Gil
2008-02-01
Many condensed matter systems are such that their collective excitations at low energies can be described by fields satisfying equations of motion formally indistinguishable from those of relativistic field theory. The finite speed of propagation of the disturbances in the effective fields (in the simplest models, the speed of sound) plays here the role of the speed of light in fundamental physics. However, these apparently relativistic fields are immersed in an external Newtonian world (the condensed matter system itself and the laboratory can be considered Newtonian, since all the velocities involved are much smaller than the velocity of light) which provides a privileged coordinate system and therefore seems to destroy the possibility of having a perfectly defined relativistic emergent world. In this essay we ask ourselves the following question: In a homogeneous condensed matter medium, is there a way for internal observers, dealing exclusively with the low-energy collective phenomena, to detect their state of uniform motion with respect to the medium? By proposing a thought experiment based on the construction of a Michelson-Morley interferometer made of quasi-particles, we show that a real Lorentz-FitzGerald contraction takes place, so that internal observers are unable to find out anything about their ‘absolute’ state of motion. Therefore, we also show that an effective but perfectly defined relativistic world can emerge in a fishbowl world situated inside a Newtonian (laboratory) system. This leads us to reflect on the various levels of description in physics, in particular regarding the quest towards a theory of quantum gravity.
NASA Astrophysics Data System (ADS)
Chä, Seok-Yeong; Fischer, Uwe R.
2017-03-01
We consider an analogue de Sitter cosmos in an expanding quasi-two-dimensional Bose-Einstein condensate with dominant dipole-dipole interactions between the atoms or molecules in the ultracold gas. It is demonstrated that a hallmark signature of inflationary cosmology, the scale invariance of the power spectrum of inflaton field correlations, experiences strong modifications when, at the initial stage of expansion, the excitation spectrum displays a roton minimum. Dipolar quantum gases thus furnish a viable laboratory tool to experimentally investigate, with well-defined and controllable initial conditions, whether primordial oscillation spectra deviating from Lorentz invariance at trans-Planckian momenta violate standard predictions of inflationary cosmology.
Invariants from classical field theory
Diaz, Rafael; Leal, Lorenzo
2008-06-15
We introduce a method that generates invariant functions from perturbative classical field theories depending on external parameters. By applying our methods to several field theories such as Abelian BF, Chern-Simons, and two-dimensional Yang-Mills theory, we obtain, respectively, the linking number for embedded submanifolds in compact varieties, the Gauss' and the second Milnor's invariant for links in S{sup 3}, and invariants under area-preserving diffeomorphisms for configurations of immersed planar curves.
Tractors, mass, and Weyl invariance
NASA Astrophysics Data System (ADS)
Gover, A. R.; Shaukat, A.; Waldron, A.
2009-05-01
Deser and Nepomechie established a relationship between masslessness and rigid conformal invariance by coupling to a background metric and demanding local Weyl invariance, a method which applies neither to massive theories nor theories which rely upon gauge invariances for masslessness. We extend this method to describe massive and gauge invariant theories using Weyl invariance. The key idea is to introduce a new scalar field which is constant when evaluated at the scale corresponding to the metric of physical interest. This technique relies on being able to efficiently construct Weyl invariant theories. This is achieved using tractor calculus—a mathematical machinery designed for the study of conformal geometry. From a physics standpoint, this amounts to arranging fields in multiplets with respect to the conformal group but with novel Weyl transformation laws. Our approach gives a mechanism for generating masses from Weyl weights. Breitenlohner-Freedman stability bounds for Anti-de Sitter theories arise naturally as do direct derivations of the novel Weyl invariant theories given by Deser and Nepomechie. In constant curvature spaces, partially massless theories—which rely on the interplay between mass and gauge invariance—are also generated by our method. Another simple consequence is conformal invariance of the maximal depth partially massless theories. Detailed examples for spins s⩽2 are given including tractor and component actions, on-shell and off-shell approaches and gauge invariances. For all spins s⩾2 we give tractor equations of motion unifying massive, massless, and partially massless theories.
LORENTZ PHASE IMAGING AND IN-SITU LORENTZ MICROSCOPY OF PATTERNED CO-ARRAYS.
VOLKOV,V.V.ZHU,Y.
2003-08-03
Understanding magnetic structures and properties of patterned and ordinary magnetic films at nanometer length-scale is the area of immense technological and fundamental scientific importance. The key feature to such success is the ability to achieve visual quantitative information on domain configurations with a maximum ''magnetic'' resolution. Several methods have been developed to meet these demands (Kerr and Faraday effects, differential phase contrast microscopy, magnetic force microscopy, SEMPA etc.). In particular, the modern off-axis electron holography allows retrieval of the electron-wave phase shifts down to 2{pi}/N (with typical N = 10-20, approaching in the limit N {approx} 100) in TEM equipped with field emission gun, which is already successfully employed for studies of magnetic materials at nanometer scale. However, it remains technically demanding, sensitive to noise and needs highly coherent electron sources. As possible alternative we developed a new method of Lorentz phase microscopy [1,2] based on the Fourier solution [3] of magnetic transport-of-intensity (MTIE) equation. This approach has certain advantages, since it is less sensitive to noise and does not need high coherence of the source required by the holography. In addition, it can be realized in any TEM without basic hardware changes. Our approach considers the electron-wave refraction in magnetic materials (magnetic refraction) and became possible due to general progress in understanding of noninterferometric phase retrieval [4-6] dealing with optical refraction. This approach can also be treated as further development of Fresnel microscopy, used so far for imaging of in-situ magnetization process in magnetic materials studied by TEM. Figs. 1-3 show some examples of what kind information can be retrieved from the conventional Fresnel images using the new approach. Most of these results can be compared with electron-holographic data. Using this approach we can shed more light on fine
Phenomenologically viable Lorentz-violating quantum gravity.
Sotiriou, Thomas P; Visser, Matt; Weinfurtner, Silke
2009-06-26
Horava's "Lifschitz point gravity" has many desirable features, but in its original incarnation one is forced to accept a nonzero cosmological constant of the wrong sign to be compatible with observation. We develop an extension of Horava's model that abandons "detailed balance" and regains parity invariance, and in 3+1 dimensions exhibit all five marginal (renormalizable) and four relevant (super-renormalizable) operators, as determined by power counting. We also consider the classical limit of this theory, evaluate the Hamiltonian and supermomentum constraints, and extract the classical equations of motion in a form similar to the Arnowitt-Deser-Misner formulation of general relativity. This puts the model in a framework amenable to developing detailed precision tests.
Very special relativity and Lorentz violating theories
NASA Astrophysics Data System (ADS)
Alfaro, Jorge; Rivelles, Victor O.
2014-06-01
Very special relativity (VSR) keeps the main features of special relativity but breaks rotational invariance. We will show how VSR like terms which depend on a fixed null vector can be generated systematically. We start with a formulation for a spinning particle which incorporates VSR. We then use this formulation to derive the VSR modifications to the Maxwell equations. Next we consider VSR corrections to Thomas precession. We start with the coupling of the spinning particle to the electromagnetic field adding a gyromagnetic factor which gives rise to a magnetic moment. We then propose a spin vector in terms of the spinning particle variables and show that it obeys the BMT equation. All this is generalized to the VSR context and we find the VSR contributions to the BMT equation.
The competition between Lorentz and Coriolis forces in planetary dynamos
NASA Astrophysics Data System (ADS)
Soderlund, Krista M.; Sheyko, Andrey; King, Eric M.; Aurnou, Jonathan M.
2015-12-01
Fluid motions within planetary cores generate magnetic fields through dynamo action. These core processes are driven by thermo-compositional convection subject to the competing influences of rotation, which tends to organize the flow into axial columns, and the Lorentz force, which tends to inhibit the relative movement of the magnetic field and the fluid. It is often argued that these forces are predominant and approximately equal in planetary cores; we test this hypothesis using a suite of numerical geodynamo models to calculate the Lorentz to Coriolis force ratio directly. Our results show that this ratio can be estimated by ( Λ i is the traditionally defined Elsasser number for imposed magnetic fields and Rm is the system-scale ratio of magnetic induction to magnetic diffusion). Best estimates of core flow speeds and magnetic field strengths predict the geodynamo to be in magnetostrophic balance where the Lorentz and Coriolis forces are comparable. The Lorentz force may also be significant, i.e., within an order of magnitude of the Coriolis force, in the Jovian interior. In contrast, the Lorentz force is likely to be relatively weak in the cores of Saturn, Uranus, Neptune, Ganymede, and Mercury.
Optimal Lorentz-augmented spacecraft formation flying in elliptic orbits
NASA Astrophysics Data System (ADS)
Huang, Xu; Yan, Ye; Zhou, Yang
2015-06-01
An electrostatically charged spacecraft accelerates as it moves through the Earth's magnetic field due to the induced Lorentz force, providing a new means of propellantless electromagnetic propulsion for orbital maneuvers. The feasibility of Lorentz-augmented spacecraft formation flying in elliptic orbits is investigated in this paper. Assuming the Earth's magnetic field as a tilted dipole corotating with Earth, a nonlinear dynamical model that characterizes the orbital motion of Lorentz spacecraft in the vicinity of arbitrary elliptic orbits is developed. To establish a predetermined formation configuration at given terminal time, pseudospectral method is used to solve the optimal open-loop trajectories of hybrid control inputs consisted of Lorentz acceleration and thruster-generated control acceleration. A nontilted dipole model is also introduced to analyze the effect of dipole tilt angle via comparisons with the tilted one. Meanwhile, to guarantee finite-time convergence and system robustness against external perturbations, a continuous fast nonsingular terminal sliding mode controller is designed and the closed-loop system stability is proved by Lyapunov theory. Numerical simulations substantiate the validity of proposed open-loop and closed-loop control schemes, and the results indicate that an almost propellantless formation establishment can be achieved by choosing appropriate objective function in the pseudospectral method. Furthermore, compared to the nonsingular terminal sliding mode controller, the closed-loop controller presents superior convergence rate with only a bit more control effort. And the proposed controller can be applied in other Lorentz-augmented relative orbital control problems.
A theoretical model for the Lorentz force particle analyzer
NASA Astrophysics Data System (ADS)
Moreau, René; Tao, Zhen; Wang, Xiaodong
2016-07-01
In a previous paper [X. Wang et al., J. Appl. Phys. 120, 014903 (2016)], several experimental devices have been presented, which demonstrate the efficiency of electromagnetic techniques for detecting and sizing electrically insulating particles entrained in the flow of a molten metal. In each case, a non-uniform magnetic field is applied across the flow of the electrically conducting liquid, thereby generating a braking Lorentz force on this moving medium and a reaction force on the magnet, which tends to be entrained in the flow direction. The purpose of this letter is to derive scaling laws for this Lorentz force from an elementary theoretical model. For simplicity, as in the experiments, the flowing liquid is modeled as a solid body moving with a uniform velocity U. The eddy currents in the moving domain are derived from the classic induction equation and Ohm's law, and expressions for the Lorentz force density j ×B and for its integral over the entire moving domain follow. The insulating particles that are eventually present and entrained with this body are then treated as small disturbances in a classic perturbation analysis, thereby leading to scaling laws for the pulses they generate in the Lorentz force. The purpose of this letter is both to illustrate the eddy currents without and with insulating particles in the electrically conducting liquid and to derive a key relation between the pulses in the Lorentz force and the main parameters (particle volume and dimensions of the region subjected to the magnetic field).
Attitude dynamics and control of spacecraft using geomagnetic Lorentz force
NASA Astrophysics Data System (ADS)
Abdel-Aziz, Yehia A.; Shoaib, Muhammad
2015-01-01
Attitude stabilization of a charged rigid spacecraft in Low Earth Orbit using torques due to Lorentz force in pitch and roll directions is considered. A spacecraft that generates an electrostatic charge on its surface in the Earth's magnetic field will be subject to perturbations from the Lorentz force. The Lorentz force acting on an electrostatically charged spacecraft may provide a useful thrust for controlling a spacecraft's orientation. We assume that the spacecraft is moving in the Earth's magnetic field in an elliptical orbit under the effects of gravitational, geomagnetic and Lorentz torques. The magnetic field of the Earth is modeled as a non-tilted dipole. A model incorporating all Lorentz torques as a function of orbital elements has been developed on the basis of electric and magnetic fields. The stability of the spacecraft orientation is investigated both analytically and numerically. The existence and stability of equilibrium positions is investigated for different values of the charge to mass ratio (α*). Stable orbits are identified for various values of α*. The main parameters for stabilization of the spacecraft are α* and the difference between the components of the moment of inertia for the spacecraft.
The scale invariant generator technique for quantifying anisotropic scale invariance
NASA Astrophysics Data System (ADS)
Lewis, G. M.; Lovejoy, S.; Schertzer, D.; Pecknold, S.
1999-11-01
Scale invariance is rapidly becoming a new paradigm for geophysics. However, little attention has been paid to the anisotropy that is invariably present in geophysical fields in the form of differential stratification and rotation, texture and morphology. In order to account for scaling anisotropy, the formalism of generalized scale invariance (GSI) was developed. Until now there has existed only a single fairly ad hoc GSI analysis technique valid for studying differential rotation. In this paper, we use a two-dimensional representation of the linear approximation to generalized scale invariance, to obtain a much improved technique for quantifying anisotropic scale invariance called the scale invariant generator technique (SIG). The accuracy of the technique is tested using anisotropic multifractal simulations and error estimates are provided for the geophysically relevant range of parameters. It is found that the technique yields reasonable estimates for simulations with a diversity of anisotropic and statistical characteristics. The scale invariant generator technique can profitably be applied to the scale invariant study of vertical/horizontal and space/time cross-sections of geophysical fields as well as to the study of the texture/morphology of fields.
Bifurcation from an invariant to a non-invariant attractor
NASA Astrophysics Data System (ADS)
Mandal, D.
2016-12-01
Switching dynamical systems are very common in many areas of physics and engineering. We consider a piecewise linear map that periodically switches between more than one different functional forms. We show that in such systems it is possible to have a border collision bifurcation where the system transits from an invariant attractor to a non-invariant attractor.
Constraints on Lorentz violation from gravitational Cerenkov radiation
Kostelecký, V. Alan; Tasson, Jay D.
2015-08-31
Limits on gravitational Cerenkov radiation by cosmic rays are obtained and used to constrain coefficients for Lorentz violation in the gravity sector associated with operators of even mass dimensions, including orientation-dependent effects. We use existing data from cosmic-ray telescopes to obtain conservative two-sided constraints on 80 distinct Lorentz-violating operators of dimensions four, six, and eight, along with conservative one-sided constraints on three others. Existing limits on the nine minimal operators at dimension four are improved by factors of up to a billion, while 74 of our explicit limits represent stringent first constraints on nonminimal operators. As a result, prospects aremore » discussed for future analyses incorporating effects of Lorentz violation in the matter sector, the role of gravitational Cerenkov radiation by high-energy photons, data from gravitational-wave observatories, the tired-light effect, and electromagnetic Cerenkov radiation by gravitons.« less
Convexity and concavity constants in Lorentz and Marcinkiewicz spaces
NASA Astrophysics Data System (ADS)
Kaminska, Anna; Parrish, Anca M.
2008-07-01
We provide here the formulas for the q-convexity and q-concavity constants for function and sequence Lorentz spaces associated to either decreasing or increasing weights. It yields also the formula for the q-convexity constants in function and sequence Marcinkiewicz spaces. In this paper we extent and enhance the results from [G.J.O. Jameson, The q-concavity constants of Lorentz sequence spaces and related inequalities, Math. Z. 227 (1998) 129-142] and [A. Kaminska, A.M. Parrish, The q-concavity and q-convexity constants in Lorentz spaces, in: Banach Spaces and Their Applications in Analysis, Conference in Honor of Nigel Kalton, May 2006, Walter de Gruyter, Berlin, 2007, pp. 357-373].
Classical kinematics for isotropic, minimal Lorentz-violating fermion operators
NASA Astrophysics Data System (ADS)
Schreck, M.
2015-05-01
In this article a particular classical, relativistic Lagrangian based on the isotropic fermion sector of the Lorentz-violating (minimal) Standard Model extension is considered. The motion of the associated classical particle in an external electromagnetic field is studied, and the evolution of its spin, which is introduced by hand, is investigated. It is shown that the particle travels along trajectories that are scaled versions of the standard ones. Furthermore there is no spin precession due to Lorentz violation, but the rate is modified at which the longitudinal and transverse spin components transform into each other. This demonstrates that it is practical to consider classical physics within such an isotropic Lorentz-violating framework and it opens the pathway to study a curved background in that context.
Lorentz-force-induced motion in conductive media.
Basford, Alexandra T; Basford, Jeffrey R; Kugel, Jennifer; Ehman, Richard L
2005-06-01
This project was designed to assess whether MRI imaging could detect Lorentz-force-induced motion in conductive samples. Experiments were performed by applying alternating voltages across 2% agar and 18% bovine gels placed in the field of a 1.5-T MRI scanner. Motion-sensitized time-gated MRI images that were obtained and analyzed with custom-developed software used in previous studies revealed the production of movement in both agar and gel samples. Motion was most pronounced in the plane vertical to the sample and had the greatest amplitude when the current path was perpendicular to the scanner's magnetic field. These findings are compatible with the vector cross product nature of the Lorentz force and suggest that the imaging of Lorentz-force-induced motion in conductive samples is feasible. Whether this approach can be extended to study electrically active tissues such as the peripheral nerves, brain and heart remains to be seen.
A Lorentz-Covariant Connection for Canonical Gravity
NASA Astrophysics Data System (ADS)
Geiller, Marc; Lachièze-Rey, Marc; Noui, Karim; Sardelli, Francesco
2011-08-01
We construct a Lorentz-covariant connection in the context of first order canonical gravity with non-vanishing Barbero-Immirzi parameter. To do so, we start with the phase space formulation derived from the canonical analysis of the Holst action in which the second class constraints have been solved explicitly. This allows us to avoid the use of Dirac brackets. In this context, we show that there is a ''unique'' Lorentz-covariant connection which is commutative in the sense of the Poisson bracket, and which furthermore agrees with the connection found by Alexandrov using the Dirac bracket. This result opens a new way toward the understanding of Lorentz-covariant loop quantum gravity.
Dynamical ambiguities in models with spontaneous Lorentz violation
NASA Astrophysics Data System (ADS)
Bonder, Yuri; Escobar, Carlos A.
2016-01-01
Spontaneous Lorentz violation is a viable mechanism to look for Planck scale physics. In this work, we study spontaneous Lorentz violation models, in flat spacetime, where a vector field produces such a violation and matter is modeled by a complex scalar field. We show that it is possible to construct a Hamilton density for which the evolution respects the dynamical constraints. However, we also find that the initial data, as required by standard field theory, does not determine the fields evolution in a unique way. In addition, we present some examples where the physical effects of such ambiguities can be recognized. As a consequence, the proposals in which the electromagnetic and gravitational interactions emerge from spontaneous Lorentz violation are challenged.
Special Relativity in Week One: 3) Introducing the Lorentz Contraction
NASA Astrophysics Data System (ADS)
Huggins, Elisha
2011-05-01
This is the third of four articles on teaching special relativity in the first week of an introductory physics course.1,2 With Einstein's second postulate that the speed of light is the same to all observers, we could use the light pulse clock to introduce time dilation. But we had difficulty introducing the Lorentz contraction until we saw the movie "Time Dilation, an Experiment with Mu-Mesons" by David Frisch and James Smith.3,4 The movie demonstrates that time dilation and the Lorentz contraction are essentially two sides of the same coin. Here we take the muon's point of view for a more intuitive understanding of the Lorentz contraction, and use the results of the movie to provide an insight into the way we interpret experimental results involving special relativity.
Spontaneous breaking of Lorentz symmetry with an antisymmetric tensor
NASA Astrophysics Data System (ADS)
Hernaski, C. A.
2016-11-01
This paper considers the spontaneous violation of Lorentz symmetry by the vacuum condensation of an antisymmetric two-tensor. The coset construction for nonlinear realization of spacetime symmetries is employed to build the most general low-energy effective action for the Goldstone modes interacting with photons. We analyze the model within the context of the Standard-Model extension and noncommutative QED. Experimental bounds for some parameters of the model are discussed, and we readdress the subtle issues of stability and causality in Lorentz-noninvariant scenarios. To set a sensible low-energy effective model, in addition to the two photon polarizations only one Goldstone mode must be dynamical, and the enhancement of the stability by accounting for interaction terms points to a protection against observational Lorentz violation.
A comparison of Lorentz, planetary gravitational, and satellite gravitational resonances
NASA Technical Reports Server (NTRS)
Hamilton, Douglas P.
1994-01-01
We consider a charged dust grain whose orbital motion is dominated by a planet's point-source gravity, but perturbed by higher-order terms in the planet's gravity field as well as by the Lorentz force arising from an asymmetric planetary magnetic field. Perturbations to Keplerian orbits due to a nonspherical gravity field are expressed in the traditional way: in terms of a disturbing function which can be expanded in a series of spherical harmonics (W. M. Kaula, 1966). In order to calculate the electromagnetic perturbation, we first write the Lorentz force in terms of the orbital elements and then substitute it into Gauss' perturbation equations. We use our result to derive strengths of Lorentz resonances and elucidate their properties. In particular, we compare Lorentz resonances to two types of gravitational resonances: those arising from periodic tugs of a satellite and those due to the attraction of an arbitrarily shaped planet. We find that Lorentz resonances share numerous properties with their gravitational counterparts and show, using simple physical arguments, that several of these patterns are fundamental, applying not only to our expansions, but to all quantities expressed in terms of orbital elements. Some of these patterns have been previously called 'd'Alembert rules' for satellite resonances. Other similarities arise because, to first-order in the perturbing force, the three problems share an integral of the motion. Yet there are also differences; for example, first-order inclination resonances exist for perturbations arising from planetary gravity and from the Lorentz force, but not for those due to an orbiting satellite. Finally, we provide a heuristic treatment of a particle's orbital evolution under the influence of drag and resonant forces. Particles brought into mean-motion resonances experience either trapping or resonant 'jumps,' depending on the direction from which the resonance is approached. We show that this behavior does not depend on
Invariant Measures for Cherry Flows
NASA Astrophysics Data System (ADS)
Saghin, Radu; Vargas, Edson
2013-01-01
We investigate the invariant probability measures for Cherry flows, i.e. flows on the two-torus which have a saddle, a source, and no other fixed points, closed orbits or homoclinic orbits. In the case when the saddle is dissipative or conservative we show that the only invariant probability measures are the Dirac measures at the two fixed points, and the Dirac measure at the saddle is the physical measure. In the other case we prove that there exists also an invariant probability measure supported on the quasi-minimal set, we discuss some situations when this other invariant measure is the physical measure, and conjecture that this is always the case. The main techniques used are the study of the integrability of the return time with respect to the invariant measure of the return map to a closed transversal to the flow, and the study of the close returns near the saddle.
Global defects in theories with Lorentz symmetry violation
Lubo, Musongela
2005-02-15
We study global topological defects in the Jacobson-Corley model which breaks Lorentz symmetry and involves up to fourth order derivatives. There is a window in the parameter space in which no solution exists. Otherwise, different profiles are allowed for the same values of the parameters. For a scale of Lorentz violation much higher than the scale of gauge symmetry breaking, the energy densities are higher, of the same order or smaller than in the usual case for domain walls, cosmic strings, and hedgehogs, respectively. Possible cosmological implications are suggested.
Global defects in theories with Lorentz symmetry violation
NASA Astrophysics Data System (ADS)
Lubo, Musongela
2005-02-01
We study global topological defects in the Jacobson-Corley model which breaks Lorentz symmetry and involves up to fourth order derivatives. There is a window in the parameter space in which no solution exists. Otherwise, different profiles are allowed for the same values of the parameters. For a scale of Lorentz violation much higher than the scale of gauge symmetry breaking, the energy densities are higher, of the same order or smaller than in the usual case for domain walls, cosmic strings, and hedgehogs, respectively. Possible cosmological implications are suggested.
Lorentz Body Force Induced by Traveling Magnetic Fields
NASA Technical Reports Server (NTRS)
Volz, M. P.; Mazuruk, K.
2003-01-01
The Lorentz force induced by a traveling magnetic field (TMF) in a cylindrical container has been calculated. The force can be used to control flow in dectrically conducting melts and the direction of the magnetic field and resulting flow can be reversed. A TMF can be used to partially cancel flow driven by buoyancy. The penetration of the field into the cylinder decreases as the frequency increases, and there exists an optimal value of frequency for which the resulting force is a maximum. Expressions for the Lorentz force in the limiting cases of low frequency and infinite cylinder are also given and compared to the numerical calculations.
On the anomalies in Lorentz-breaking theories
NASA Astrophysics Data System (ADS)
Baêta Scarpelli, A. P.; Mariz, T.; Nascimento, J. R.; Yu. Petrov, A.
2016-04-01
In this paper, we discuss the chiral anomaly in a Lorentz-breaking extension of QED which, besides the common terms that are present in the Standard Model Extension, includes some dimension-five nonminimal couplings. We find, using the Fujikawa formalism, that these nonminimal couplings induce new terms in the anomaly which depend on the Lorentz-violating parameters. Perturbative calculations are also carried out in order to investigate whether new ambiguous Carroll-Field-Jackiw terms are induced in the effective action.
Physical Invariants of Intelligence
NASA Technical Reports Server (NTRS)
Zak, Michail
2010-01-01
A program of research is dedicated to development of a mathematical formalism that could provide, among other things, means by which living systems could be distinguished from non-living ones. A major issue that arises in this research is the following question: What invariants of mathematical models of the physics of systems are (1) characteristic of the behaviors of intelligent living systems and (2) do not depend on specific features of material compositions heretofore considered to be characteristic of life? This research at earlier stages has been reported, albeit from different perspectives, in numerous previous NASA Tech Briefs articles. To recapitulate: One of the main underlying ideas is to extend the application of physical first principles to the behaviors of living systems. Mathematical models of motor dynamics are used to simulate the observable physical behaviors of systems or objects of interest, and models of mental dynamics are used to represent the evolution of the corresponding knowledge bases. For a given system, the knowledge base is modeled in the form of probability distributions and the mental dynamics is represented by models of the evolution of the probability densities or, equivalently, models of flows of information. At the time of reporting the information for this article, the focus of this research was upon the following aspects of the formalism: Intelligence is considered to be a means by which a living system preserves itself and improves its ability to survive and is further considered to manifest itself in feedback from the mental dynamics to the motor dynamics. Because of the feedback from the mental dynamics, the motor dynamics attains quantum-like properties: The trajectory of the physical aspect of the system in the space of dynamical variables splits into a family of different trajectories, and each of those trajectories can be chosen with a probability prescribed by the mental dynamics. From a slightly different perspective
Vay, J-L
2007-03-30
We present an analysis which shows that the ranges of space and time scales spanned by a system are not invariant under Lorentz transformation. This implies the existence of a frame of reference which minimizes an aggregate measure of the range of space and time scales. Such a frame is derived, for example, for the following cases: free electron laser, laser-plasma accelerator, and particle beams interacting with electron clouds. The implications for experimental, theoretical, and numerical studies are discussed. The most immediate relevance is the reduction by orders of magnitude in computer simulation run times for such systems.
Vay, J.-L.; Vay, J.-L.
2007-11-12
We present an analysis which shows that the ranges of space and time scales spanned by a system are not invariant under the Lorentz transformation. This implies the existence of a frame of reference which minimizes an aggregate measure of the range of space and time scales. Such a frame is derived for example cases: free electron laser, laser-plasma accelerator, and particle beam interacting with electron clouds. Implications for experimental, theoretical and numerical studies are discussed. The most immediate relevance is the reduction by orders of magnitude in computer simulation run times for such systems.
Vay, J.-L.
2007-03-30
We present an analysis which shows that the ranges of space and time scales spanned by a system are not invariant under Lorentz transformation. This implies the existence of a frame of reference which minimizes an aggregate measure of the range of space and time scales. Such a frame is derived, for example, for the following cases: free electron laser, laser-plasma accelerator, and particle beams interacting with electron clouds. The implications for experimental, theoretical, and numerical studies are discussed. The most immediate relevance is the reduction by orders of magnitude in computer simulation run times for such system000.
Insensitivity of Hawking radiation to an invariant Planck-scale cutoff
Agullo, Ivan; Navarro-Salas, Jose; Olmo, Gonzalo J.; Parker, Leonard
2009-08-15
A disturbing aspect of Hawking's derivation of black hole radiance is the need to invoke extreme conditions for the quantum field that originates the emitted quanta. It is widely argued that the derivation requires the validity of the conventional relativistic field theory to arbitrarily high, trans-Planckian scales. We stress in this note that this is not necessarily the case if the question is presented in a covariant way. We point out that Hawking radiation is immediately robust against an invariant Planck-scale cutoff. This important feature of Hawking radiation is relevant for a quantum gravity theory that preserves, in some way, the Lorentz symmetry.
BPS Maxwell-Chern Vortices in a Lorentz-Violating Framework
NASA Astrophysics Data System (ADS)
Casana, R.; Ferreira, M. M.; Hora, E. Da; Neves, A. B. F.
2014-01-01
We have analyzed Maxwell-Chern-Simons-Higgs BPS vortices in a Lorentz-violating CPT-odd context. The Lorentz violation induces profiles with a conical behavior at the origin. For some combination of the coefficients for Lorentz violation there always exists a sufficiently large winding number for which the magnetic field flips its sign.
Round Table Discussion at the Lorentz Workshop "beyond the Quantum"
NASA Astrophysics Data System (ADS)
Cetto, A. M.; Balian, R.; 't Hooft, G.; Khrennikov, A. Yu.; Nieuwenhuizen, Th. M.
2007-09-01
This is a transcript of the round table discussion, moderated by G. 't Hooft, that took place at the end of the workshop "Beyond The Quantum" in the Lorentz Center of the University of Leiden, the Netherlands, 29 May - 2 June 2006. It displays current views on foundations of quantum mechanics.
Lorentz estimates for degenerate and singular evolutionary systems
NASA Astrophysics Data System (ADS)
Baroni, Paolo
We prove estimates of Calderón-Zygmund type for evolutionary p-Laplacian systems in the setting of Lorentz spaces. We suppose the coefficients of the system to satisfy only a VMO condition with respect to the space variable. Our results hold true, mutatis mutandis, also for stationary p-Laplacian systems.
Lorentz transformations in the presence of a uniform gravitational field.
NASA Technical Reports Server (NTRS)
Broucke, R.
1971-01-01
This article describes a Lorentz-like transformation between a fixed frame and an inertial frame that is free falling due to the presence of a uniform gravitation field. The application to the clock paradox problem and some connections with similar works are also discussed.
A More Intuitive Version of the Lorentz Velocity Addition Formula
ERIC Educational Resources Information Center
Devlin, John F.
2009-01-01
The Lorentz velocity addition formula for one-dimensional motion presents a number of problems for beginning students of special relativity. In this paper we suggest a simple rewrite of the formula that is easier for students to memorize and manipulate, and furthermore is more intuitive in understanding the correction necessary when adding…
Special Relativity in Week One: 3) Introducing the Lorentz Contraction
ERIC Educational Resources Information Center
Huggins, Elisha
2011-01-01
This is the third of four articles on teaching special relativity in the first week of an introductory physics course. With Einstein's second postulate that the speed of light is the same to all observers, we could use the light pulse clock to introduce time dilation. But we had difficulty introducing the Lorentz contraction until we saw the movie…
Constraints on torsion from bounds on lorentz violation.
Kostelecký, V Alan; Russell, Neil; Tasson, Jay D
2008-03-21
Exceptional sensitivity to space-time torsion can be achieved by searching for its couplings to fermions. Recent experimental searches for Lorentz violation are exploited to extract new constraints involving 19 of the 24 independent torsion components down to levels of order 10(-31) GeV.
Constraints on nonmetricity from bounds on Lorentz violation
NASA Astrophysics Data System (ADS)
Foster, Joshua; Kostelecký, V. Alan; Xu, Rui
2017-04-01
Spacetime nonmetricity can be studied experimentally through its couplings to fermions and photons. We use recent high-precision searches for Lorentz violation to deduce first constraints involving the 40 independent nonmetricity components down to levels of order 10-43 GeV .
Lorentz- and CPT-symmetry studies in subatomic physics
NASA Astrophysics Data System (ADS)
Lehnert, Ralf
2016-12-01
Subatomic systems provide an exquisite test bench for spacetime symmetries. This work motivates such measurements, reviews the effective field theory test framework for the description of Lorentz and CPT violation, and employs this framework to study the phenomenology of spacetime-symmetry breaking in various subatomic systems.
Special Relativity in Week One: 3) Introducing the Lorentz Contraction
ERIC Educational Resources Information Center
Huggins, Elisha
2011-01-01
This is the third of four articles on teaching special relativity in the first week of an introductory physics course. With Einstein's second postulate that the speed of light is the same to all observers, we could use the light pulse clock to introduce time dilation. But we had difficulty introducing the Lorentz contraction until we saw the movie…
Particle-Like Solution of the Maxwell-Lorentz Equations
NASA Astrophysics Data System (ADS)
Lasukova, T. V.; Lasukov, V. V.; Abdrashitova, M. O.
2017-09-01
It is shown that the Maxwell-Lorentz equations with a nonlinear source of field type can have solutions which asymptotically are solutions of soliton type, so that the electromagnetic field can be localized in space, and the corresponding electromagnetic soliton can move with nonrelativistic velocity.
A More Intuitive Version of the Lorentz Velocity Addition Formula
ERIC Educational Resources Information Center
Devlin, John F.
2009-01-01
The Lorentz velocity addition formula for one-dimensional motion presents a number of problems for beginning students of special relativity. In this paper we suggest a simple rewrite of the formula that is easier for students to memorize and manipulate, and furthermore is more intuitive in understanding the correction necessary when adding…
Lorentz transformations in the presence of a uniform gravitational field.
NASA Technical Reports Server (NTRS)
Broucke, R.
1971-01-01
This article describes a Lorentz-like transformation between a fixed frame and an inertial frame that is free falling due to the presence of a uniform gravitation field. The application to the clock paradox problem and some connections with similar works are also discussed.
Lorentz Transformation Derived from First-Order Experiments
ERIC Educational Resources Information Center
Pfleiderer, J.
1969-01-01
Suggests a first-order experiment that can be used to establish the Lorentz transformation without considering the constancy of light velocity or the full set of Maxwell's equations. Involves the use of a long solenoid to create an electric field in a moving magnetic field. (LC)
A Useful Device for Illustrating the Lorentz Transformations
ERIC Educational Resources Information Center
Cortini, Giulio
1972-01-01
A graphical representation is proposed as a teaching device which can be useful in order to obtain a good intuitive grasp of the physical meaning of the Lorentz transformations. The connection between the time dilation and the desynchronization of clocks is particularly discussed. (Author/PR)
On the conformal geometry of transverse Riemann Lorentz manifolds
NASA Astrophysics Data System (ADS)
Aguirre, E.; Fernández, V.; Lafuente, J.
2007-06-01
Physical reasons suggested in [J.B. Hartle, S.W. Hawking, Wave function of the universe, Phys. Rev. D41 (1990) 1815-1834] for the Quantum Gravity Problem lead us to study type-changing metrics on a manifold. The most interesting cases are Transverse Riemann-Lorentz Manifolds. Here we study the conformal geometry of such manifolds.
Einstein's gravitation as a gauge theory of the Lorentz group
Fustero, X.; Gambini, R.; Trias, A.
1985-06-15
The gauge principle in the loop space is invoked to produce the gauge theory of the Lorentz group. The full kinematics of gravitation is derived from this principle. The dynamics is introduced with a gauge ''matter field'' Lagrangian which leads to the sourceless Einstein equations. Some possibilities about quantization and implementation on the lattice are suggested.
Lorentz force actuation of a heated atomic force microscope cantilever
NASA Astrophysics Data System (ADS)
Lee, Byeonghee; Prater, Craig B.; King, William P.
2012-02-01
We report Lorentz force-induced actuation of a silicon microcantilever having an integrated resistive heater. Oscillating current through the cantilever interacts with the magnetic field around a NdFeB permanent magnet and induces a Lorentz force that deflects the cantilever. The same current induces cantilever heating. With AC currents as low as 0.2 mA, the cantilever can be oscillated as much as 80 nm at resonance with a DC temperature rise of less than 5 °C. By comparison, the AC temperature variation leads to a thermomechanical oscillation that is about 1000 times smaller than the Lorentz deflection at the cantilever resonance. The cantilever position in the nonuniform magnetic field affects the Lorentz force-induced deflection, with the magnetic field parallel to the cantilever having the largest effect on cantilever actuation. We demonstrate how the cantilever actuation can be used for imaging, and for measuring the local material softening temperature by sensing the contact resonance shift.
Noncommutative spaces, the quantum of time, and Lorentz symmetry
Romero, Juan M.; Vergara, J. D.; Santiago, J. A.
2007-03-15
We introduce three space-times that are discrete in time and compatible with the Lorentz symmetry. We show that these spaces are not commutative, with commutation relations similar to the relations of the Snyder and Yang spaces. Furthermore, using a reparametrized relativistic particle we obtain a realization of the Snyder type spaces and we construct an action for them.
Lorentz-violating effects in three-dimensional QED
NASA Astrophysics Data System (ADS)
Bufalo, R.
2014-08-01
Inspired in discussions presented lately regarding Lorentz-violating interaction terms in B. Charneski, M. Gomes, R. V. Maluf and A. J. da Silva, Phys. Rev. D86, 045003 (2012); R. Casana, M. M. Ferreira Jr., R. V. Maluf and F. E. P. dos Santos, Phys. Lett. B726, 815 (2013); R. Casana, M. M. Ferreira Jr., E. Passos, F. E. P. dos Santos and E. O. Silva, Phys. Rev. D87, 047701 (2013), we propose here a slightly different version for the coupling term. We will consider a modified quantum electrodynamics with violation of Lorentz symmetry defined in a (2+1)-dimensional space-time. We define the Lagrangian density with a Lorentz-violating interaction, where the space-time dimensionality is explicitly taken into account in its definition. The work encompasses an analysis of this model at both zero and finite-temperature, where very interesting features are known to occur due to the space-time dimensionality. With that in mind, we expect that the space-time dimensionality may provide new insights about the radiative generation of higher-derivative terms into the action, implying in a new Lorentz-violating electrodynamics, as well the nonminimal coupling may provide interesting implications on the thermodynamical quantities.
Lorentz Transformation Derived from First-Order Experiments
ERIC Educational Resources Information Center
Pfleiderer, J.
1969-01-01
Suggests a first-order experiment that can be used to establish the Lorentz transformation without considering the constancy of light velocity or the full set of Maxwell's equations. Involves the use of a long solenoid to create an electric field in a moving magnetic field. (LC)
Shape Invariance in Deformation Quantization
NASA Astrophysics Data System (ADS)
Rasinariu, Constantin
2013-03-01
Shape invariance is a powerful solvability condition, that allows for complete knowledge of the energy spectrum, and eigenfunctions of a system. After a short introduction into the deformation quantization formalism, this work explores the implications of the supersymmetric quantum mechanics and shape invariance techniques to the phase space formalism. We show that shape invariance induces a new set of relations between the Wigner functions of the system, that allows for their direct calculation, once we know one of them. The simple harmonic oscillator and the Morse potential are presented as examples. I would like to acknowledge a sabbatical leave and grant from Columbia College Chicago that made this work possible.
Shape invariance through Crum transformation
Organista, Jose Orlando; Nowakowski, Marek; Rosu, H. C.
2006-12-15
We show in a rigorous way that Crum's result regarding the equal eigenvalue spectrum of Sturm-Liouville problems can be obtained iteratively by successive Darboux transformations. Furthermore, it can be shown that all neighboring Darboux-transformed potentials of higher order, u{sub k} and u{sub k+1}, satisfy the condition of shape invariance provided the original potential u does so. Based on this result, we prove that under the condition of shape invariance, the nth iteration of the original Sturm-Liouville problem defined solely through the shape invariance is equal to the nth Crum transformation.
Bayesian tests of measurement invariance.
Verhagen, A J; Fox, J P
2013-11-01
Random item effects models provide a natural framework for the exploration of violations of measurement invariance without the need for anchor items. Within the random item effects modelling framework, Bayesian tests (Bayes factor, deviance information criterion) are proposed which enable multiple marginal invariance hypotheses to be tested simultaneously. The performance of the tests is evaluated with a simulation study which shows that the tests have high power and low Type I error rate. Data from the European Social Survey are used to test for measurement invariance of attitude towards immigrant items and to show that background information can be used to explain cross-national variation in item functioning.
Quadratic Generalized Scale Invariance
NASA Astrophysics Data System (ADS)
Lovejoy, S.; Schertzer, D.; Addor, J. B.
Nearly twenty years ago, two of us argued that in order to account for the scaling strat- ification of the atmosphere, that an anisotropic "unified scaling model" of the atmo- sphere was required with elliptical dimension 23/9=2.555... "in between" the standard 3-D (small scale) and 2-D large scale model. This model was based on the formal- ism of generalized scale invariance (GSI). Physically, GSI is justified by arguing that various conserved fluxes (energy, buoyancy force variance etc.) should define the ap- propriate notion of scale. In a recent large scale satellite cloud image analysis, we directly confirmed this model by studying the isotropic (angle averaged) horizontal cloud statistics. Mathematically, GSI is based on a a group of scale changing opera- tors and their generators but to date, both analyses (primarily of cloud images) and nu- merical (multifractal) simulations, have been limited to the special case of linear GSI. This has shown that cloud texture can plausibly be associated with local linearizations. However realistic morphologies involve spatially avarying textures; the full non linear GSI is clearly necessary. In this talk, we first show that the observed angle averaged (multi)scaling statistics only give a realtively weak constraint on the nonlinear gner- ator: that the latter can be expressed by self-similar (isotropic) part, and a deviatoric part described (in two dimensions) by an arbitrary scalar potential which contains all the information about the cloud morphology. We then show (using a theorem due to Poincaré) how to reduce nonlinear GSI to linear GSI plus a nonlinear coordinate trans- formation numerically, using this to take multifractal GSI modelling to the next level of approximation: quadratic GSI. We show many examples of the coresponding simu- lations which include transitions from various morphologies (including cyclones) and we discuss the results in relation to satellite cloud images.
Invariant measures in brain dynamics
NASA Astrophysics Data System (ADS)
Boyarsky, Abraham; Góra, Paweł
2006-10-01
This note concerns brain activity at the level of neural ensembles and uses ideas from ergodic dynamical systems to model and characterize chaotic patterns among these ensembles during conscious mental activity. Central to our model is the definition of a space of neural ensembles and the assumption of discrete time ensemble dynamics. We argue that continuous invariant measures draw the attention of deeper brain processes, engendering emergent properties such as consciousness. Invariant measures supported on a finite set of ensembles reflect periodic behavior, whereas the existence of continuous invariant measures reflect the dynamics of nonrepeating ensemble patterns that elicit the interest of deeper mental processes. We shall consider two different ways to achieve continuous invariant measures on the space of neural ensembles: (1) via quantum jitters, and (2) via sensory input accompanied by inner thought processes which engender a “folding” property on the space of ensembles.
Orthosymplectically invariant functions in superspace
NASA Astrophysics Data System (ADS)
Coulembier, K.; De Bie, H.; Sommen, F.
2010-08-01
The notion of spherically symmetric superfunctions as functions invariant under the orthosymplectic group is introduced. This leads to dimensional reduction theorems for differentiation and integration in superspace. These spherically symmetric functions can be used to solve orthosymplectically invariant Schrödinger equations in superspace, such as the (an)harmonic oscillator or the Kepler problem. Finally, the obtained machinery is used to prove the Funk-Hecke theorem and Bochner's relations in superspace.
Average intensity and spreading of a Lorentz-Gauss beam in turbulent atmosphere.
Zhou, Guoquan; Chu, Xiuxiang
2010-01-18
The propagation of a Lorentz-Gauss beam in turbulent atmosphere is investigated. Based on the extended Huygens-Fresnel integral and the Hermite-Gaussian expansion of a Lorentz function, analytical formulae for the average intensity and the effective beam size of a Lorentz-Gauss beam are derived in turbulent atmosphere. The average intensity distribution and the spreading properties of a Lorentz-Gauss beam in turbulent atmosphere are numerically demonstrated. The influences of the beam parameters and the structure constant of the atmospheric turbulence on the propagation of a Lorentz-Gauss beam in turbulent atmosphere are also discussed in detail.
Hidden scale invariance of metals
NASA Astrophysics Data System (ADS)
Hummel, Felix; Kresse, Georg; Dyre, Jeppe C.; Pedersen, Ulf R.
2015-11-01
Density functional theory (DFT) calculations of 58 liquid elements at their triple point show that most metals exhibit near proportionality between the thermal fluctuations of the virial and the potential energy in the isochoric ensemble. This demonstrates a general "hidden" scale invariance of metals making the condensed part of the thermodynamic phase diagram effectively one dimensional with respect to structure and dynamics. DFT computed density scaling exponents, related to the Grüneisen parameter, are in good agreement with experimental values for the 16 elements where reliable data were available. Hidden scale invariance is demonstrated in detail for magnesium by showing invariance of structure and dynamics. Computed melting curves of period three metals follow curves with invariance (isomorphs). The experimental structure factor of magnesium is predicted by assuming scale invariant inverse power-law (IPL) pair interactions. However, crystal packings of several transition metals (V, Cr, Mn, Fe, Nb, Mo, Ta, W, and Hg), most post-transition metals (Ga, In, Sn, and Tl), and the metalloids Si and Ge cannot be explained by the IPL assumption. The virial-energy correlation coefficients of iron and phosphorous are shown to increase at elevated pressures. Finally, we discuss how scale invariance explains the Grüneisen equation of state and a number of well-known empirical melting and freezing rules.
Class of gauge-invariant models of quantum electrodynamics with nonlocal interaction
Mei, Tao
2017-01-01
We present a class of gauge-invariant models of quantum electrodynamics with nonlocal interaction. The models have translation, Lorentz and gauge invariance and reduce to the conventional local quantum electrodynamics under the appropriate limit conditions, both the equations of motion of the charged particle and electromagnetic field obtained by the action principle lead to the normal form of current conservation. Quantization of the models is realized by taking advantage of the formalism based on the Yang-Feldman equations and the Lehmann-Symanzik-Zimmermann reduction formulas. Finally, we employ a special choice of the models to calculate the vacuum polarization as an example to demonstrate the possibility of establishing a theory of quantum electrodynamics without divergence. PMID:28368044
Class of gauge-invariant models of quantum electrodynamics with nonlocal interaction.
Mei, Tao
2017-04-03
We present a class of gauge-invariant models of quantum electrodynamics with nonlocal interaction. The models have translation, Lorentz and gauge invariance and reduce to the conventional local quantum electrodynamics under the appropriate limit conditions, both the equations of motion of the charged particle and electromagnetic field obtained by the action principle lead to the normal form of current conservation. Quantization of the models is realized by taking advantage of the formalism based on the Yang-Feldman equations and the Lehmann-Symanzik-Zimmermann reduction formulas. Finally, we employ a special choice of the models to calculate the vacuum polarization as an example to demonstrate the possibility of establishing a theory of quantum electrodynamics without divergence.
Gauge-invariant Lagrangians for mixed-antisymmetric higher spin fields
NASA Astrophysics Data System (ADS)
Reshetnyak, A. A.
2017-03-01
Lagrangian descriptions of integer HS representations of the Poincare group subject to a Young tableaux Y[ {\\hat s}_1,{\\hat s}_2 ] with two columns are constructed within a metric-like formulation in a d-dimensional flat space-time on a basis of the BRST approach. A Lorentz-invariant resolution of the BRST complex within BRST formulations produces a gauge-invariant Lagrangian in terms of the initial tensor field Φ _[ μ ]_{\\hat s}_1,[ μ ]_{\\hat s}_2 subject to Y[ {\\hat s}_1,{\\hat s}_2 ] with an additional tower of gauge parameters realizing the ( {\\hat s}_1 - 1 )-th stage reducible theory with a specific dependence on the value ( {\\hat s}_1 - {\\hat s}_2 ) = 0,1, \\ldots {\\hat s_1}. Minimal BRST-BV action is suggested, providing objects appropriate to construct interacting models with mixed-antisymmetric fields in a general framework.
Class of gauge-invariant models of quantum electrodynamics with nonlocal interaction
NASA Astrophysics Data System (ADS)
Mei, Tao
2017-04-01
We present a class of gauge-invariant models of quantum electrodynamics with nonlocal interaction. The models have translation, Lorentz and gauge invariance and reduce to the conventional local quantum electrodynamics under the appropriate limit conditions, both the equations of motion of the charged particle and electromagnetic field obtained by the action principle lead to the normal form of current conservation. Quantization of the models is realized by taking advantage of the formalism based on the Yang-Feldman equations and the Lehmann-Symanzik-Zimmermann reduction formulas. Finally, we employ a special choice of the models to calculate the vacuum polarization as an example to demonstrate the possibility of establishing a theory of quantum electrodynamics without divergence.
Why Do We Believe the Speed of Light is an Invariant of Nature?
NASA Astrophysics Data System (ADS)
Smith, Felix T.
2014-03-01
We believe it, obviously, because we believe in relativity, and Einstein based his treatment of relativity on what he named ``The Principle of Constancy of the Velocity of Light.'' From Einstein's own writings between 1905 and about 1912 we know that in defining what this meant he was concerned especially about two issues: One was to deny the notion that the transmission of light required a privileged ``ether'' frame; the other was that the velocity of a light signal measured by an observer is independent of the velocity of the source that emitted the signal with respect to the observer. In relativity Einstein's two Principles made a handy brief basis from which he could deduce the requirement of covariance under the transformations of the Lorentz group. These transformations had been developed earlier by Lorentz to conform with the results of experiments, without requiring constancy of c. The Lorentz group only requires that c be an upper bound greater than all observed particle or signal velocities. The assumption of its invariance over cosmological time seems justified mostly by its convenience as a teaching and mnemonic oversimplification.
Weyl invariance with a nontrivial mass scale
Álvarez, Enrique; González-Martín, Sergio
2016-09-07
A theory with a mass scale and yet Weyl invariant is presented. The theory is not invariant under all diffeomorphisms but only under transverse ones. This is the reason why Weyl invariance does not imply scale invariance in a free falling frame. Physical implications of this framework are discussed.
Scale invariance and invariant scaling in a mixed hierarchical system.
Shnirman, M G; Blanter, E M
1999-11-01
We consider a mixed hierarchical model with heterogeneous and monotone conditions of destruction. We investigate how scaling properties of defects in the model are related with heterogeneity of rules of destruction, determined by concentration of the mixture. The system demonstrates different kinds of criticality as a general form of system behavior. The following forms of critical behavior are obtained: stability, catastrophe, scale invariance, and invariant scaling. Different slopes of the magnitude-frequency relation are realized in areas of critical stability and catastrophe. A simple relation between the slope of magnitude-frequency relation and parameters of the mixture is established.
The local geometry of compact homogeneous Lorentz spaces
NASA Astrophysics Data System (ADS)
Günther, Felix
2015-03-01
In 1995, S. Adams and G. Stuck as well as A. Zeghib independently provided a classification of non-compact Lie groups which can act isometrically and locally effectively on compact Lorentzian manifolds. In the case that the corresponding Lie algebra contains a direct summand isomorphic to the two-dimensional special linear algebra or to a twisted Heisenberg algebra, Zeghib also described the geometric structure of the manifolds. Using these results, we investigate the local geometry of compact homogeneous Lorentz spaces whose isometry groups have non-compact connected components. It turns out that they all are reductive. We investigate the isotropy representation and curvatures. In particular, we obtain that any Ricci-flat compact homogeneous Lorentz space is flat or has compact isometry group.
Manipulating the Lorentz force via the chirality of nanoparticles
NASA Astrophysics Data System (ADS)
Wang, Maoyan; Li, Hailong; Dong, Yuliang; Zhang, Xiaochuan; Du, Ming; Wang, Rui; Xu, Tong; Wu, Jian
2016-12-01
We demonstrate that a single plane wave pulls a chiral nanoparticle toward the light source. The nanoparticle exhibits optical gain in a particular wavelength region. The equivalence of the generalized and alternative expressions of the Lorentz force density relating to bound charges for chiral media is numerically validated. By considering the two-dimensional electromagnetic problem of incident plane waves normally impinged on active chiral cylinders, it is shown that the gradient force is mainly contributed by the bound electric and magnetic current densities of the cross-polarized waves. We also investigate how the medium parameters and impedance mismatch can be used to manipulate the pulling or pushing Lorentz forces between two chiral cylinders. This finding may provide a recipe to understand the light interaction with multiple chiral nanoparticles of arbitrary shapes (in general) with the aid of the numerical approach. It could be a promising avenue in controlling the optical micromanipulation for chiral nanoparticles with mirroring asymmetry.
Impact of Lorentz violation on the dynamics of inflation
Avelino, P. P.; Bazeia, D.; Losano, L.; Rodrigues, J. J.; Menezes, R.
2009-06-15
This work deals with the dynamics of inflation in the context of a scalar-vector-tensor theory of gravity exhibiting spontaneous Lorentz violation at early times. We describe a first-order formalism which we use to obtain new exact Lorentz violating inflationary solutions for a broad family of models, some in the absence of a potential for the inflaton field. Our results show that different conditions are required to solve the horizon and flatness problems. In particular, we find a necessary condition for inflation to provide a solution to both problems and we show that in inflationary models with no inflaton potential a period of superinflation might be necessary to solve the flatness problem.
Projected constraints on Lorentz-violating gravity with gravitational waves
NASA Astrophysics Data System (ADS)
Hansen, Devin; Yunes, Nicolás; Yagi, Kent
2015-04-01
Gravitational waves are excellent tools to probe the foundations of general relativity in the strongly dynamical and nonlinear regime. One such foundation is Lorentz symmetry, which can be broken in the gravitational sector by the existence of a preferred time direction and, thus, a preferred frame at each spacetime point. This leads to a modification in the orbital decay rate of binary systems, and also in the generation and chirping of their associated gravitational waves. Here we study whether waves emitted in the late, quasicircular inspiral of nonspinning, neutron star binaries can place competitive constraints on two proxies of gravitational Lorentz violation: Einstein-Æther theory and khronometric gravity. We model the waves in the small-coupling (or decoupling) limit and in the post-Newtonian approximation, by perturbatively solving the field equations in small deformations from general relativity and in the small-velocity or weak-gravity approximation. We assume that a gravitational wave consistent with general relativity has been detected with second- and third-generation, ground-based detectors, and with the proposed space-based mission DECIGO, with and without coincident electromagnetic counterparts. Without a counterpart, a detection consistent with general relativity can only place competitive constraints on gravitational Lorentz violation when using future, third-generation or space-based instruments. On the other hand, a single counterpart is enough to place constraints that are 10 orders of magnitude more stringent than current binary pulsar bounds, even when using second-generation detectors. This is because Lorentz violation forces the group velocity of gravitational waves to be different from that of light, and this difference can be very accurately constrained with coincident observations.
Einstein and Lorentz: The structure of a scientific revolution
NASA Astrophysics Data System (ADS)
Brouwer, W.
1980-06-01
In a course entitled ''Revolutions in Physics'' a number of episodes in the history of physics are examined, in order to test the theories of Kuhn, Popper, Lakatos, and others, with regard to any common structure exhibited by the various revolutions that physics has undergone. The conflict between Lorentz's Electron Theory and Einstein's Special Relativity becomes a major focal point in the second half of the course for the models of scientific revolutions that are studied.
Two field BPS solutions for generalized Lorentz breaking models
Souza Dutra, A. de; Hott, M.; Barone, F. A.
2006-10-15
In this work we present nonlinear models in two-dimensional space-time of two interacting scalar fields in the Lorentz and CPT violating scenarios. We discuss the soliton solutions for these models as well as the question of stability for them. This is done by generalizing a model recently published by Barreto and collaborators and also by getting new solutions for the model introduced by them.
Extending the Lorentz Transformation to Motion with Variable Velocity
NASA Technical Reports Server (NTRS)
Jones, Robert T.
1959-01-01
The problem considered is that of rectilinear motion with variable velocity. The paper gives, by an elementary construction, a system of coordinates which is conformal in the vicinity of the axis of motion. By a particular choice of the scale relation, such restricted conformal transformations can be made to reduce to the Lorentz transformation everywhere in the case of uniform velocity and locally in the case of variable velocity.
Shape of solitons in classically forbidden states - 'Lorentz expansion'
NASA Technical Reports Server (NTRS)
Guinea, F.; Peierls, R. E.; Schrieffer, R.
1986-01-01
The shape of extended objects in classically forbidden regions is shown to undergo expansion analogous to Lorentz contraction of a relativistic body of finite velocities. The problem of two interacting Dirac particles moving in one dimension is solved explicitly and the results are generalized to soliton solutions of field theories. An estimate of the effect on tunneling rates is also given, including solitons in (CH)z.
Remote sub-wavelength focusing of ultrasonically activated Lorentz current
NASA Astrophysics Data System (ADS)
Rekhi, Angad S.; Arbabian, Amin
2017-04-01
We propose the use of a combination of ultrasonic and magnetic fields in conductive media for the creation of RF electrical current via the Lorentz force, in order to achieve current generation with extreme sub-wavelength resolution at large depth. We demonstrate the modeling, generation, and measurement of Lorentz current in a conductive solution and show that this current can be localized at a distance of 13 cm from the ultrasonic source to a region about three orders of magnitude smaller than the corresponding wavelength of electromagnetic waves at the same operation frequency. Our results exhibit greater depth, tighter localization, and closer agreement with prediction than previous work on the measurement of Lorentz current in a solution of homogeneous conductivity. The proposed method of RF current excitation overcomes the trade-off between focusing and propagation that is fundamental in the use of RF electromagnetic excitation alone and has the potential to improve localization and depth of operation for RF current-based biomedical applications.
Vacuum Plasma Spray Forming of Tungsten Lorentz Force Accelerator Components
NASA Technical Reports Server (NTRS)
Zimmerman, Frank R.
2004-01-01
The Vacuum Plasma Spray (VPS) Laboratory at NASA's Marshall Space Flight Center, working with the Jet Propulsion Laboratory, has developed and demonstrated a fabrication technique using the VPS process to form anode and cathode sections for a Lorentz force accelerator made from tungsten. Lorentz force accelerators are an attractive form of electric propulsion that provides continuous, high-efficiency propulsion at useful power levels for such applications as orbit transfers or deep space missions. The VPS process is used to deposit refractory metals such as tungsten onto a graphite mandrel of the desired shape. Because tungsten is reactive at high temperatures, it is thermally sprayed in an inert environment where the plasma gun melts and deposits the molten metal powder onto a mandrel. A three-axis robot inside the chamber controls the motion of the plasma spray torch. A graphite mandrel acts as a male mold, forming the required contour and dimensions for the inside surface of the anode or cathode of the accelerator. This paper describes the processing techniques, design considerations, and process development associated with the VPS forming of Lorentz force accelerator components.
Vacuum Plasma Spray Forming of Tungsten Lorentz Force Accelerator Components
NASA Technical Reports Server (NTRS)
Zimmerman, Frank R.
2001-01-01
The Vacuum Plasma Spray (VPS) Laboratory at NASA's Marshall Space Flight Center has developed and demonstrated a fabrication technique using the VPS process to form anode sections for a Lorentz force accelerator from tungsten. Lorentz force accelerators are an attractive form of electric propulsion that provides continuous, high-efficiency propulsion at useful power levels for such applications as orbit transfers or deep space missions. The VPS process is used to deposit refractory metals such as tungsten onto a graphite mandrel of the desired shape. Because tungsten is reactive at high temperatures, it is thermally sprayed in an inert environment where the plasma gun melts and accelerates the metal powder onto the mandrel. A three-axis robot inside the chamber controls the motion of the plasma spray torch. A graphite mandrel acts as a male mold, forming the required contour and dimensions of the inside surface of the anode. This paper describes the processing techniques, design considerations, and process development associated with the VPS forming of the Lorentz force accelerator.
Vacuum Plasma Spray Forming of Tungsten Lorentz Force Accelerator Components
NASA Technical Reports Server (NTRS)
Zimmerman, Frank R.
2001-01-01
The Vacuum Plasma Spray (VPS) Laboratory at NASA's Marshall Space Flight Center has developed and demonstrated a fabrication technique using the VPS process to form anode sections for a Lorentz force accelerator from tungsten. Lorentz force accelerators are an attractive form of electric propulsion that provides continuous, high-efficiency propulsion at useful power levels for such applications as orbit transfers or deep space missions. The VPS process is used to deposit refractory metals such as tungsten onto a graphite mandrel of the desired shape. Because tungsten is reactive at high temperatures, it is thermally sprayed in an inert environment where the plasma gun melts and accelerates the metal powder onto the mandrel. A three-axis robot inside the chamber controls the motion of the plasma spray torch. A graphite mandrel acts as a male mold, forming the required contour and dimensions of the inside surface of the anode. This paper describes the processing techniques, design considerations, and process development associated with the VPS forming of the Lorentz force accelerator.
Vacuum Plasma Spray Forming of Tungsten Lorentz Force Accelerator Components
NASA Technical Reports Server (NTRS)
Zimmerman, Frank R.
2004-01-01
The Vacuum Plasma Spray (VPS) Laboratory at NASA's Marshall Space Flight Center, working with the Jet Propulsion Laboratory, has developed and demonstrated a fabrication technique using the VPS process to form anode and cathode sections for a Lorentz force accelerator made from tungsten. Lorentz force accelerators are an attractive form of electric propulsion that provides continuous, high-efficiency propulsion at useful power levels for such applications as orbit transfers or deep space missions. The VPS process is used to deposit refractory metals such as tungsten onto a graphite mandrel of the desired shape. Because tungsten is reactive at high temperatures, it is thermally sprayed in an inert environment where the plasma gun melts and deposits the molten metal powder onto a mandrel. A three-axis robot inside the chamber controls the motion of the plasma spray torch. A graphite mandrel acts as a male mold, forming the required contour and dimensions for the inside surface of the anode or cathode of the accelerator. This paper describes the processing techniques, design considerations, and process development associated with the VPS forming of Lorentz force accelerator components.
Control of heat transfer in engine coolers by Lorentz forces
NASA Astrophysics Data System (ADS)
Karcher, C.; Kühndel, J.
2016-09-01
In engine coolers of off-highway vehicles convective heat transfer at the coolant side is a limiting factor of both efficiency and performance density of the cooler. Here, due to design restrictions, backwater areas and stagnation regions appear that are caused by flow deflections and cross-sectional expansions. As appropriate coolants, mixtures of water and glysantine are commonly used. Such coolants are characterized by their electrical conductivity of some S/m. This gives rise to control coolant flow and therefore convective heat transfer by means of Lorentz forces. These body forces are generated within the weakly conducting fluid by the interactions of an electrical current density and a localized magnetic field both of which being externally superimposed. In application this may be achieved by inserting electrodes in the cooler wall and a corresponding arrangement of permanent magnets. In this paper we perform numerical simulations of such magnetohydrodynamic flow in three model geometries that are frequently apparent in engine cooling applications: Carnot-Borda diffusor, 90° bend, and 180° bend. The simulations are carried out using the software package ANSYS Fluent. The present study demonstrates that, depending on the electromagnetic interaction parameter and the specific geometric arrangement of electrodes and magnetic field, Lorentz forces are suitable to break up eddy waters and separation zones and are thus significantly increasing convective heat transfer in these areas. Furthermore, the results show that due to the action of the Lorentz forces the hydraulic pressure losses can be reduced.
Lorentz constraints on massive three-point amplitudes
NASA Astrophysics Data System (ADS)
Conde, Eduardo; Marzolla, Andrea
2016-09-01
Using the helicity-spinor language we explore the non-perturbative constraints that Lorentz symmetry imposes on three-point amplitudes where the asymptotic states can be massive. As it is well known, in the case of only massless states the three-point amplitude is fixed up to a coupling constant by these constraints plus some physical requirements. We find that a similar statement can be made when some of the particles have mass. We derive the generic functional form of the three-point amplitude by virtue of Lorentz symmetry, which displays several functional structures accompanied by arbitrary constants. These constants can be related to the coupling constants of the theory, but in an unambiguous fashion only in the case of one massive particle. Constraints on these constants are obtained by imposing that in the UV limit the massive amplitude matches the massless one. In particular, there is a certain Lorentz frame, which corresponds to projecting all the massive momenta along the same null momentum, where the three-point massive amplitude is fully fixed, and has a universal form.
Abelian link invariants and homology
Guadagnini, Enore; Mancarella, Francesco
2010-06-15
We consider the link invariants defined by the quantum Chern-Simons field theory with compact gauge group U(1) in a closed oriented 3-manifold M. The relation of the Abelian link invariants with the homology group of the complement of the links is discussed. We prove that, when M is a homology sphere or when a link--in a generic manifold M--is homologically trivial, the associated observables coincide with the observables of the sphere S{sup 3}. Finally, we show that the U(1) Reshetikhin-Turaev surgery invariant of the manifold M is not a function of the homology group only, nor a function of the homotopy type of M alone.
Invariance concepts in spectral analysis
NASA Astrophysics Data System (ADS)
Schaum, Alan
2017-05-01
Methods are developed for insuring robust discrimination performance in detection problems with epistemic unknowns. The problem is first solved for the class of problems exhibiting some symmetry, as expressed by invariances to some group of feature space transformations. The determination of whether a problem admits a uniformly most powerful invariant (UMPI) solution (and how to derive it) is solved with a new and simple procedure. This motivates an approach for solving problems where a symmetry is gracefully broken, which leads in turn to a general approach for producing robust detectors. This introduces a new category of detector, the UMPIC (UMPI constrained). Finally, principles of UMPIC construction are shown to apply to problems exhibiting no invariances.
Test of charge conjugation invariance.
Nefkens, B M K; Prakhov, S; Gårdestig, A; Allgower, C E; Bekrenev, V; Briscoe, W J; Clajus, M; Comfort, J R; Craig, K; Grosnick, D; Isenhower, D; Knecht, N; Koetke, D; Koulbardis, A; Kozlenko, N; Kruglov, S; Lolos, G; Lopatin, I; Manley, D M; Manweiler, R; Marusić, A; McDonald, S; Olmsted, J; Papandreou, Z; Peaslee, D; Phaisangittisakul, N; Price, J W; Ramirez, A F; Sadler, M; Shafi, A; Spinka, H; Stanislaus, T D S; Starostin, A; Staudenmaier, H M; Supek, I; Tippens, W B
2005-02-04
We report on the first determination of upper limits on the branching ratio (BR) of eta decay to pi0pi0gamma and to pi0pi0pi0gamma. Both decay modes are strictly forbidden by charge conjugation (C) invariance. Using the Crystal Ball multiphoton detector, we obtained BR(eta-->pi0pi0gamma)<5 x 10(-4) at the 90% confidence level, in support of C invariance of isoscalar electromagnetic interactions of the light quarks. We have also measured BR(eta-->pi0pi0pi0gamma)<6 x 10(-5) at the 90% confidence level, in support of C invariance of isovector electromagnetic interactions.
Energy Invariance in Capillary Systems.
Ruiz-Gutiérrez, Élfego; Guan, Jian H; Xu, Ben; McHale, Glen; Wells, Gary G; Ledesma-Aguilar, Rodrigo
2017-05-26
We demonstrate the continuous translational invariance of the energy of a capillary surface in contact with reconfigurable solid boundaries. We present a theoretical approach to find the energy-invariant equilibria of spherical capillary surfaces in contact with solid boundaries of arbitrary shape and examine the implications of dynamic frictional forces upon a reconfiguration of the boundaries. Experimentally, we realize our ideas by manipulating the position of a droplet in a wedge geometry using lubricant-impregnated solid surfaces, which eliminate the contact-angle hysteresis and provide a test bed for quantifying dissipative losses out of equilibrium. Our experiments show that dissipative energy losses for an otherwise energy-invariant reconfiguration are relatively small, provided that the actuation time scale is longer than the typical relaxation time scale of the capillary surface. We discuss the wider applicability of our ideas as a pathway for liquid manipulation at no potential energy cost in low-pinning, low-friction situations.
Energy Invariance in Capillary Systems
NASA Astrophysics Data System (ADS)
Ruiz-Gutiérrez, Élfego; Guan, Jian H.; Xu, Ben; McHale, Glen; Wells, Gary G.; Ledesma-Aguilar, Rodrigo
2017-05-01
We demonstrate the continuous translational invariance of the energy of a capillary surface in contact with reconfigurable solid boundaries. We present a theoretical approach to find the energy-invariant equilibria of spherical capillary surfaces in contact with solid boundaries of arbitrary shape and examine the implications of dynamic frictional forces upon a reconfiguration of the boundaries. Experimentally, we realize our ideas by manipulating the position of a droplet in a wedge geometry using lubricant-impregnated solid surfaces, which eliminate the contact-angle hysteresis and provide a test bed for quantifying dissipative losses out of equilibrium. Our experiments show that dissipative energy losses for an otherwise energy-invariant reconfiguration are relatively small, provided that the actuation time scale is longer than the typical relaxation time scale of the capillary surface. We discuss the wider applicability of our ideas as a pathway for liquid manipulation at no potential energy cost in low-pinning, low-friction situations.
A generalization of gauge invariance
NASA Astrophysics Data System (ADS)
Grigore, Dan-Radu
2017-08-01
We consider perturbative quantum field theory in the causal framework. Gauge invariance is, in this framework, an identity involving chronological products of the interaction Lagrangian; it expresses the fact that the scattering matrix must leave invariant the sub-space of physical states. We are interested in generalizations of such identity involving Wick sub-monomials of the interaction Lagrangian. The analysis can be performed by direct computation in the lower orders of perturbation theory; guided by these computations, we conjecture a generalization for arbitrary orders.
Invariants of broken discrete symmetries.
Kalozoumis, P A; Morfonios, C; Diakonos, F K; Schmelcher, P
2014-08-01
The parity and Bloch theorems are generalized to the case of broken global symmetry. Local inversion or translation symmetries in one dimension are shown to yield invariant currents that characterize wave propagation. These currents map the wave function from an arbitrary spatial domain to any symmetry-related domain. Our approach addresses any combination of local symmetries, thus applying, in particular, to acoustic, optical, and matter waves. Nonvanishing values of the invariant currents provide a systematic pathway to the breaking of discrete global symmetries.
Invariants of Broken Discrete Symmetries
NASA Astrophysics Data System (ADS)
Kalozoumis, P. A.; Morfonios, C.; Diakonos, F. K.; Schmelcher, P.
2014-08-01
The parity and Bloch theorems are generalized to the case of broken global symmetry. Local inversion or translation symmetries in one dimension are shown to yield invariant currents that characterize wave propagation. These currents map the wave function from an arbitrary spatial domain to any symmetry-related domain. Our approach addresses any combination of local symmetries, thus applying, in particular, to acoustic, optical, and matter waves. Nonvanishing values of the invariant currents provide a systematic pathway to the breaking of discrete global symmetries.
Lorentz violation bounds from torsion trace fermion sector and galaxy M 51 data and chiral dynamos
NASA Astrophysics Data System (ADS)
Garcia de Andrade, L. C.
2017-06-01
Earlier we have computed a Lorentz violation (LV) bound for torsion terms via galactic dynamos and found bounds similar to the one obtained by Kostelecky et al. (Phys Rev Lett 100:111102, 2008) which is of the order of 10^{-31} GeV. Their result was found making use of the axial torsion vector in terms of Dirac spinors and minimal torsion coupling in flat space-time of fermions. In this paper, a torsion dynamo equation obtained using the variation of the torsion trace and galaxy M51 data of 500 pc are used to place an upper bound of 10^{-26} GeV in LV, which agrees with the one by Kostelecky and his group using an astrophysical framework background. Their lowest bound was obtained in earth laboratory using dual masers. One of the purposes of this paper is to apply the Faraday self-induction magnetic equation, recently extended to torsioned space-time, by the author to show that it lends support to physics in Riemann-Cartan space-time, in several distinct physical backgrounds. Backreaction magnetic effects are used to obtain the LV bounds. Previously Bamba et al. (JCAP 10:058, 2012) have used the torsion trace in their teleparallel investigation of the IGMF, with the argument that the torsion trace leads to less weaker effects than the other irreducible components of the torsion tensor. LV is computed in terms of a chiral-torsion-like current in the new dynamo equation analogous to the Dvornikov and Semikoz dynamo equation with chiral magnetic currents. Making use of the chiral-torsion dynamo equation we estimate the LV bounds in the early universe to be of the order of 10^{-24} GeV, which was the order of the charged-lepton sector. Our main result is that it is possible to obtain more stringent bounds than the ones found in the fermion sector of astrophysics in the new revised 2017 data table for CPT and Lorentz violation by Kostelecky and Mewes. They found in several astrophysical backgrounds, orders of magnitude such as 10^{-24} and 10^{-23} GeV which are not so
Constraints on torsion from the bosonic sector of Lorentz violation and magnetogenesis data
NASA Astrophysics Data System (ADS)
Garcia de Andrade, L. C.
2011-06-01
A. Kostelecky et al. [Phys. Rev. Lett. 100 (2008) 111102], have shown that there is an exceptional sensitivity of spacetime torsion components by coupling it to fermions and constraining it to Lorentz violation. They obtain new constraints on torsion components down to the level of 10 GeV. Yet more recently, L.C. Garcia de Andrade [Phys. Lett. B 468 (2011) 28] has shown that the photon sector of Lorentz violation (LV) Lagrangian leads to linear non-standard Maxwell equations where the magnetic field decays slower giving rise to a seed for galactic dynamos. In this paper bounds are placed on torsion based on the magnetogenesis or the origin of magnetic fields in the universe. On a coherence scale of 10 kpc, galactic magnetic fields of the order of some μG yield a torsion primordial field of the order of K≈10 GeV. Just to give an idea of how tiny it is we mention that torsion limit in the Early universe yield K≈10 GeV had been obtained by V. de Sabbata and C. Sivaram. Good limits were also obtained by B.R. Heckel et al. [Phys. Rev. D 78 (2008) 092006]. In our case the advantage from astro-particle physics point of view, is that a very small seed torsion field is enough to seed galactic dynamo. C. Sivaram limit is obtained from a massive photon electrodynamics [L.C. Garcia de Andrade, C. Sivaram, Ap. Space Sci. 209 (1993) 109] where a gauge invariant electrodynamics is used. Dynamo stars data are able to raise this value of torsion up to 10 GeV at magnetar atmosphere. From these estimates one notices that they coincide with the ones obtained by A. Kostelecky et al., the difference being basically in the method. The ones here were obtained from magnetogenesis data while theirs were obtained from the Earth laboratory data from polarised electrons. Besides here one used the torsion derivatives while A. Kostelecky et al. uses the constant axial torsion tensor. Another fundamental distinction is that we use bosonic sector of the Lagrangian while they use mainly
NASA Technical Reports Server (NTRS)
Purvis, C. K.; Taylor, P. L.
1982-01-01
A method for computing the Lorentz tensor components in single crystals via rapidly convergent sums of Bessels functions is developed using the relationship between dipole-field sums and the tensor components. The Lorentz factors for simple, body-centered, and base-centered orthorhombic lattices are computed using this method, and the derivative Lorentz factors for simple orthorhombic lattices are also determined. Both the Lorentz factors and their derivatives are shown to be very sensitive to a lattice structure. The equivalent of the Clausius-Mossotti relation for general orthorhombic lattices is derived using the Lorentz-factor formalism, and the permanent molecular dipole moment is related to crystal polarization for the case of a ferroelectric of polarizable point dipoles. It is concluded that the polarization enhancement due to self-polarization familiar from classical theory may actually be a reduction in consequences of negative Lorentz factors in one or two lattice directions for noncubic crystals.
Parameterization of the Lorentz to Coriolis Force Ratio in Planetary Dynamos
NASA Astrophysics Data System (ADS)
Soderlund, K. M.; Sheyko, A. A.; King, E. M.; Aurnou, J. M.
2015-12-01
The Lorentz to Coriolis force ratio is an important parameter for the dynamics of planetary cores: it is expected that dynamos with dominant Coriolis forces will be driven by fundamentally different archetypes of fluid motions than those with co-dominant Lorentz forces. Using a suite of geodynamo simulations, we have tested several parameterizations of the Lorentz to Coriolis force ratio against direct calculations and developed a scaling estimate to predict this ratio for planetary cores. Our results suggest that the Earth's core is likely to be in magnetostrophic balance where the Lorentz and Coriolis forces are comparable. The Lorentz force may also be significant in Jupiter's core, where it is predicted to be approximately a factor of ten less than the Coriolis force. Magnetic fields become increasingly sub-dominant for the other planets: the Coriolis force is predicted to exceed the Lorentz force by at least two orders of magnitude within the cores of Saturn, Uranus/Neptune, Ganymede, and Mercury.
Thomas, Anthony W.
2008-10-13
We discuss recent theoretical progress in understanding the distribution of spin and orbital angular momentum in the proton. Particular attention is devoted to the effect of QCD evolution and to the distinction between 'chiral' and 'invariant' spin. This is particularly significant with respect to the possible presence of polarized strange quarks.
Algebraic invariants for homotopy types
NASA Astrophysics Data System (ADS)
Blanc, David
1999-11-01
We define a sequence of purely algebraic invariants - namely, classes in the Quillen cohomology of the [Pi]-algebra [pi][low asterisk]X - for distinguishing between different homotopy types of spaces. Another sequence of such cohomology classes allows one to decide whether a given abstract [Pi]-algebra can be realized as the homotopy [Pi]-algebra of a space.
Galilean invariance in Lagrangian mechanics
NASA Astrophysics Data System (ADS)
Mohallem, J. R.
2015-10-01
The troublesome topic of Galilean invariance in Lagrangian mechanics is discussed in two situations: (i) A particular case involving a rheonomic constraint in uniform motion and (ii) the general translation of an entire system and the constants of motion involved. A widespread impropriety in most textbooks is corrected, concerning a condition for the equality h = E to hold.
Conformal invariant vacuum nonlinear electrodynamics
NASA Astrophysics Data System (ADS)
Denisov, V. I.; Dolgaya, E. E.; Sokolov, V. A.; Denisova, I. P.
2017-08-01
In this paper, a general case of conformal invariant vacuum nonlinear electrodynamics is studied. We analyze the consistency of this electrodynamics model with fundamental principles such as causality, unitarity, and the Ellis-Hawking dominant energy condition. Certain features of the electromagnetic waves in this model are investigated.
Boundary state from Ellwood invariants
NASA Astrophysics Data System (ADS)
Kudrna, Matěj; Maccaferri, Carlo; Schnabl, Martin
2013-07-01
Boundary states are given by appropriate linear combinations of Ishibashi states. Starting from any open string field theory solution and assuming Ellwood conjecture we show that every coefficient of such a linear combination is given by an Ellwood invariant, computed in a slightly modified theory where it does not trivially vanish by the on-shell condition. Unlike the previous construction of Kiermaier, Okawa and Zwiebach, ours is linear in the string field, it is manifestly gauge invariant and it is also suitable for solutions known only numerically. The correct boundary state is readily reproduced in the case of known analytic solutions and, as an example, we compute the energy momentum tensor of the rolling tachyon from the generalized invariants of the corresponding solution. We also compute the energy density profile of Siegel-gauge multiple lump solutions and show that, as the level increases, it correctly approaches a sum of delta functions. This provides a gauge invariant way of computing the separations between the lower dimensional D-branes.
NASA Astrophysics Data System (ADS)
Lopez-Sarrion, Justo; Reyes, Carlos M.
2013-04-01
We study a generalization of the Pais-Uhlenbeck oscillator for fermionic variables. Next, we consider an ensemble of these oscillators and we identify a particular case of the Myers-Pospelov model which is relevant for effective theories of quantum gravity. Finally, by taking advantage of this connection, we analyze, for this model, unitarity at one loop order in the low energy regime where no ghost states can be created on-shell. This energy regime is the relevant one when we consider the Myers-Pospelov model as a true effective theory coming from a new space-time structure.
NASA Astrophysics Data System (ADS)
M, Haritha; P, Durganandini
2015-06-01
We study the scattering and confinement of Dirac particles in external electrostatic and Lorentz scalar potentials. We use a numerical finite difference time -domain method to solve the equation and obtain the particle dynamics. We find qualitatively different dynamical behavior for electrostatic and Lorentz scalar potentials. Electrostatic potentials lead to Klein tunneling and do not exhibit confinement, while Lorentz scalar potentials inhibit Klein tunneling and exhibit confinement.
Cohomological invariants of central simple algebras
NASA Astrophysics Data System (ADS)
Merkurjev, A. S.
2016-10-01
We determine the indecomposable degree 3 cohomological invariants of tuples of central simple algebras with linear relations. Equivalently, we determine the degree 3 reductive cohomological invariants of all split semisimple groups of type A.
Measurement invariance versus selection invariance: is fair selection possible?
Borsboom, Denny; Romeijn, Jan-Willem; Wicherts, Jelte M
2008-06-01
This article shows that measurement invariance (defined in terms of an invariant measurement model in different groups) is generally inconsistent with selection invariance (defined in terms of equal sensitivity and specificity across groups). In particular, when a unidimensional measurement instrument is used and group differences are present in the location but not in the variance of the latent distribution, sensitivity and positive predictive value will be higher in the group at the higher end of the latent dimension, whereas specificity and negative predictive value will be higher in the group at the lower end of the latent dimension. When latent variances are unequal, the differences in these quantities depend on the size of group differences in variances relative to the size of group differences in means. The effect originates as a special case of Simpson's paradox, which arises because the observed score distribution is collapsed into an accept-reject dichotomy. Simulations show the effect can be substantial in realistic situations. It is suggested that the effect may be partly responsible for overprediction in minority groups as typically found in empirical studies on differential academic performance. A methodological solution to the problem is suggested, and social policy implications are discussed. (PsycINFO Database Record (c) 2008 APA, all rights reserved).
Gauge invariance, current conservation, and GIAO's
NASA Technical Reports Server (NTRS)
Epstein, S. T.
1972-01-01
The well known relationship between gauge invariance and current conservation is exhibited within the usual quantum mechanical formalism. It is then shown that the use of gauge-invariant atomic orbitals (GIAO) does not necessarily lead to the expected current conservation. The reason is found to lie in the constrained nature of the gauge invariance which is provided by the use of GIAO's. It is concluded that this invariance is, of itself, no argument in favor of their use.
Direct measurement of correlation functions in a lattice Lorentz gas
NASA Technical Reports Server (NTRS)
Binder, P.-M.; Frenkel, D.
1990-01-01
Simulations of a two-dimensional ballistic Lorentz gas on a lattice are reported. A moment-propagation technique allows direct measurements of the velocity correlation function and its moments with low relative errors for all times. The predicted 1/t-sq algebraic tails in the velocity correlation function are observed at all studied scatterer densities, unlike what has been reported for continuous systems. In the square lattice a fast oscillation is observed, consistent with the existence of staggered density modes. For the second-rank tensor correlation function, an extremely slow approach to the expected 1/t exp 3 tail is found.
New limits on Planck scale Lorentz violation in QED.
Jacobson, T; Liberati, S; Mattingly, D; Stecker, F W
2004-07-09
Constraints on possible Lorentz symmetry violation (LV) of order E/M(Planck) for electrons and photons in the framework of effective field theory (EFT) are discussed. Using (i) the report of polarized MeV emission from GRB021206 and (ii) the absence of vacuum Cerenkov radiation from synchrotron electrons in the Crab Nebula, we improve previous bounds by 10(-10) and 10(-2), respectively. We also show that the LV parameters for positrons and electrons are different, discuss electron helicity decay, and investigate how prior constraints are modified by the relations between LV parameters implied by EFT.
Fluctuation theorem for currents in the Spinning Lorentz Gas
NASA Astrophysics Data System (ADS)
Salazar, A.; Leyvraz, F.; Larralde, H.
2009-11-01
We study the fluctuation theorem formulated in terms of the currents present in a Hamiltonian system with coupled mass and energy transport. To drive the system out of equilibrium, we assume it to be connected to two ideal thermodynamical baths. The fluctuation symmetry is, thus, expressed in terms of the joint probability distribution of energy and particle currents in the system. This relation is verified numerically for the stationary state in the Spinning Lorentz Gas (SLG), driven out of equilibrium by temperature and/or chemical potential differences between the baths, as well as in the presence of an applied field.
The Lorentz gas in Kaluza's MHD: Transport equations
NASA Astrophysics Data System (ADS)
Sandoval-Villalbazo, Alfredo; Sagaceta-Mejia, Alma Rocio; Mondragon-Suarez, Jose Humberto
2016-11-01
Relativistic kinetic theory is applied to the study of the transport processes present in a Lorentz gas, using a geometric five-dimensional space-time. While the conventional transport equations are recovered in the Newtonian limit, it is shown that relativistic corrections to the conduction and diffusion fluxes arise within this formalism. A brief review of the conceptual advantages of the Kaluza-type approach to magnetohydrodynamics is also given. The authors acknowledge support from CONACyT through Grant CB2011/167563.
New limit on signals of Lorentz violation in electrodynamics.
Lipa, J A; Nissen, J A; Wang, S; Stricker, D A; Avaloff, D
2003-02-14
We describe the results of an experiment to test for spacetime anisotropy terms that might exist from Lorentz violations. The apparatus consists of a pair of cylindrical superconducting cavity-stabilized oscillators operating in the TM010 mode with one axis east-west and the other vertical. Spatial anisotropy is detected by monitoring the beat frequency at the sidereal rate and its first harmonic. We see no anisotropy to a part in 10(13). This puts a comparable bound on four linear combinations of parameters in the general standard model extension, and a weaker bound of < 4 x 10(-9) on three others.
Properties of a consistent Lorentz-violating Abelian gauge theory
Alexandre, J.; Vergou, A.
2011-06-15
A Lorentz-violating modification of massless QED is proposed, with higher-order space derivatives for the photon field. The fermion dynamical mass generation is studied with the Schwinger-Dyson approach. Perturbative properties of the model are calculated at one-loop and discussed at higher-order loops, showing the consistency of the model. We explain that there is no contradiction with the definition of the speed of light c, although fermions see an effective light cone, with a maximum speed smaller than c.
Chaos properties and localization in Lorentz lattice gases
NASA Astrophysics Data System (ADS)
Appert, C.; Ernst, M. H.
1997-11-01
The thermodynamic formalism of Ruelle, Sinai, and Bowen [David Ruelle, Thermodynamic Formalism (Addison-Wesley, Reading, MA, 1978)], in which chaotic properties of dynamical systems are expressed in terms of a free-energy-type function ψ(β), is applied to a Lorentz lattice gas, as typical for diffusive systems with static disorder. In the limit of large system sizes, the mechanism and effects of localization on large clusters of scatterers in the calculation of ψ(β) are elucidated and supported by strong numerical evidence. Moreover, we clarify and illustrate a previous theoretical analysis [C. Appert et al., J. Stat. Phys. 87, 1253 (1997)] of this localization phenomenon.
Fluctuation formula for nonreversible dynamics in the thermostated Lorentz gas
NASA Astrophysics Data System (ADS)
Dolowschiák, M.; Kovács, Z.
2002-12-01
We investigate numerically the validity of the Gallavotti-Cohen fluctuation formula in the two- and three-dimensional periodic Lorentz gas subjected to constant electric and magnetic fields and thermostated by the Gaussian isokinetic thermostat. The magnetic field breaks the time reversal symmetry, and by choosing its orientation with respect to the lattice, one can have either a generalized reversing symmetry or no reversibility at all. Our results indicate that the scaling property described by the fluctuation formula may be approximately valid for large fluctuations even in the absence of reversibility.
Fluctuation formula for nonreversible dynamics in the thermostated Lorentz gas.
Dolowschiák, M; Kovács, Z
2002-12-01
We investigate numerically the validity of the Gallavotti-Cohen fluctuation formula in the two- and three-dimensional periodic Lorentz gas subjected to constant electric and magnetic fields and thermostated by the Gaussian isokinetic thermostat. The magnetic field breaks the time reversal symmetry, and by choosing its orientation with respect to the lattice, one can have either a generalized reversing symmetry or no reversibility at all. Our results indicate that the scaling property described by the fluctuation formula may be approximately valid for large fluctuations even in the absence of reversibility.
Invariance in Measurement and Prediction Revisited
ERIC Educational Resources Information Center
Millsap, Roger E.
2007-01-01
Borsboom (Psychometrika, 71:425-440, 2006) noted that recent work on measurement invariance (MI) and predictive invariance (PI) has had little impact on the practice of measurement in psychology. To understand this contention, the definitions of MI and PI are reviewed, followed by results on the consistency between the two forms of invariance in…
Measuring Scale Invariance between and within Subjects.
ERIC Educational Resources Information Center
Benson, Jeri; Hocevar, Dennis
The present paper represents a demonstration of how LISREL V can be used to investigate scale invariance (1) across time (its relationship to test-retest reliability), and (2) across groups. Five criteria were established to test scale invariance across time and four criteria were established to test scale invariance across groups. Using the…
Anisotropic invariance in minisuperspace models
NASA Astrophysics Data System (ADS)
Chagoya, Javier; Sabido, Miguel
2016-06-01
In this paper we introduce invariance under anisotropic transformations to cosmology. This invariance is one of the key ingredients of the theory of quantum gravity at a Lifshitz point put forward by Hořava. We find that this new symmetry in the minisuperspace introduces characteristics to the model that can be relevant in the ultraviolet regime. For example, by canonical quantization we find a Schrödinger-type equation which avoids the problem of frozen time in quantum cosmology. For simple cases we obtain solutions to this quantum equation in a Kantowski-Sachs (KS) minisuperspace. At the classical level, we study KS and Friedmann-Robertson-Walker cosmologies, obtaining modifications to the solutions of general relativity that can be relevant in the early Universe.
Proton spin: A topological invariant
NASA Astrophysics Data System (ADS)
Tiwari, S. C.
2016-11-01
Proton spin problem is given a new perspective with the proposition that spin is a topological invariant represented by a de Rham 3-period. The idea is developed generalizing Finkelstein-Rubinstein theory for Skyrmions/kinks to topological defects, and using non-Abelian de Rham theorems. Two kinds of de Rham theorems are discussed applicable to matrix-valued differential forms, and traces. Physical and mathematical interpretations of de Rham periods are presented. It is suggested that Wilson lines and loop operators probe the local properties of the topology, and spin as a topological invariant in pDIS measurements could appear with any value from 0 to ℏ 2, i.e. proton spin decomposition has no meaning in this approach.
Geometry-invariant resonant cavities
NASA Astrophysics Data System (ADS)
Liberal, I.; Mahmoud, A. M.; Engheta, N.
2016-03-01
Resonant cavities are one of the basic building blocks in various disciplines of science and technology, with numerous applications ranging from abstract theoretical modelling to everyday life devices. The eigenfrequencies of conventional cavities are a function of their geometry, and, thus, the size and shape of a resonant cavity is selected to operate at a specific frequency. Here we demonstrate theoretically the existence of geometry-invariant resonant cavities, that is, resonators whose eigenfrequencies are invariant with respect to geometrical deformations of their external boundaries. This effect is obtained by exploiting the unusual properties of zero-index metamaterials, such as epsilon-near-zero media, which enable decoupling of the temporal and spatial field variations in the lossless limit. This new class of resonators may inspire alternative design concepts, and it might lead to the first generation of deformable resonant devices.
Geometry-invariant resonant cavities
Liberal, I.; Mahmoud, A. M.; Engheta, N.
2016-01-01
Resonant cavities are one of the basic building blocks in various disciplines of science and technology, with numerous applications ranging from abstract theoretical modelling to everyday life devices. The eigenfrequencies of conventional cavities are a function of their geometry, and, thus, the size and shape of a resonant cavity is selected to operate at a specific frequency. Here we demonstrate theoretically the existence of geometry-invariant resonant cavities, that is, resonators whose eigenfrequencies are invariant with respect to geometrical deformations of their external boundaries. This effect is obtained by exploiting the unusual properties of zero-index metamaterials, such as epsilon-near-zero media, which enable decoupling of the temporal and spatial field variations in the lossless limit. This new class of resonators may inspire alternative design concepts, and it might lead to the first generation of deformable resonant devices. PMID:27010103
Conformal invariance for Wilson actions
NASA Astrophysics Data System (ADS)
Sonoda, H.
2017-08-01
We discuss the realization of conformal invariance for Wilson actions using the formalism of the exact renormalization group. This subject has been studied extensively in the recent works of O. J. Rosten. The main purpose of this paper is to reformulate Rosten's formulas for conformal transformations using a method developed earlier for the realization of any continuous symmetry in the exact renormalization group formalism. The merit of the reformulation is simplicity and transparency via the consistent use of equation-of-motion operators. We derive equations that imply the invariance of the Wilson action under infinitesimal conformal transformations which are non-linearly realized but form a closed conformal algebra. The best effort has been made to make the paper self-contained; ample background on the formalism is provided.
Emerging universe from scale invariance
Del Campo, Sergio; Herrera, Ramón; Guendelman, Eduardo I.; Labraña, Pedro E-mail: guendel@bgu.ac.il E-mail: plabrana@ubiobio.cl
2010-06-01
We consider a scale invariant model which includes a R{sup 2} term in action and show that a stable ''emerging universe'' scenario is possible. The model belongs to the general class of theories, where an integration measure independent of the metric is introduced. To implement scale invariance (S.I.), a dilaton field is introduced. The integration of the equations of motion associated with the new measure gives rise to the spontaneous symmetry breaking (S.S.B) of S.I. After S.S.B. of S.I. in the model with the R{sup 2} term (and first order formalism applied), it is found that a non trivial potential for the dilaton is generated. The dynamics of the scalar field becomes non linear and these non linearities are instrumental in the stability of some of the emerging universe solutions, which exists for a parameter range of the theory.
Casual Set Approach to a Minimal Invariant Length
NASA Astrophysics Data System (ADS)
Raut, Usha
2007-04-01
Any attempt to quantize gravity would necessarily introduce a minimal observable length scale of the order of the Planck length. This conclusion is based on several different studies and thought experiments and appears to be an inescapable feature of all quantum gravity theories, irrespective of the method used to quantize gravity. Over the last few years there has been growing concern that such a minimal length might lead to a contradiction with the basic postulates of special relativity, in particular the Lorentz-Fitzgerald contraction. A few years ago, Rovelli et.al, attempted to reconcile an invariant minimal length with Special Relativity, using the framework of loop quantum gravity. However, the inherently canonical formalism of the loop quantum approach is plagued by a variety of problems, many brought on by separation of space and time co-ordinates. In this paper we use a completely different approach. Using the framework of the causal set paradigm, along with a statistical measure of closeness between Lorentzian manifolds, we re-examine the issue of introducing a minimal observable length that is not at odds with Special Relativity postulates.
Invariant Foliation of Dynamical Spacetimes
NASA Astrophysics Data System (ADS)
Tiemblo, A.; Tresguerres, R.
1998-02-01
We present a gauge-theoretical derivation of the Frobenius foliation condition. It is based on a nonlinear coset realization of the Poincaré group, implying the time component ϑ0 of the coframe to be invariant. By means of the unitary gauge fixing of the boosts, three Goldstone-like degrees of freedom of ϑ0 are eliminated. The remaining Higgs-like boson, satisfying the foliation condition, plays the role of time.
Invariant amplitudes for pion electroproduction
NASA Astrophysics Data System (ADS)
Pasquini, B.; Drechsel, D.; Tiator, L.
2007-12-01
The invariant amplitudes for pion electroproduction on the nucleon are evaluated by dispersion relations at constant t with MAID as input for the imaginary parts of these amplitudes. In the threshold region these amplitudes are confronted with the predictions of several low-energy theorems derived in the soft-pion limit. In general agreement with chiral perturbation theory, the dispersive approach yields large corrections to these theorems because of the finite pion mass.
Holographic multiverse and conformal invariance
Garriga, Jaume; Vilenkin, Alexander E-mail: vilenkin@cosmos.phy.tufts.edu
2009-11-01
We consider a holographic description of the inflationary multiverse, according to which the wave function of the universe is interpreted as the generating functional for a lower dimensional Euclidean theory. We analyze a simple model where transitions between inflationary vacua occur through bubble nucleation, and the inflating part of spacetime consists of de Sitter regions separated by thin bubble walls. In this model, we present some evidence that the dual theory is conformally invariant in the UV.