On the Lorentz Factor of Superluminal Sources
Onuchukwu, Chika Christian
2013-01-01
We investigate the properties of features seen within superluminal sources often referred to as components. Our result indicates a fairly strong correlation of r=0.6 for quasars, r=0.4 for galaxies, and r=0.8 for BL Lac objects in our sample between component sizes and distances from the stationary core. Assumption of free adiabatic expanding plasma enabled us to constrain in general the Lorentz factor for superluminal sources. Ourestimated Lorentz factor of 7 - 17 for quasars, 6 - 13 for galaxies and 4- 9 for BL Lac objects indicate that BL Lac have the lowest range of Lorentz factor.
On the Lorentz factor of superluminal sources
Institute of Scientific and Technical Information of China (English)
Chika Christian Onuchukwu; Augustine A.Ubachukwu
2013-01-01
We investigate the properties of features seen within superluminal sources often referred to as components.Our result indicates a fairly strong correlation of r ～ 0.5 for quasars,r ～ 0.4 for galaxies and r ～ 0.7 for BL Lac objects in our sample between component sizes and distances from the stationary core.The assumption of free adiabatic expanding plasma enables us to constrain the Lorentz factor for superluminal sources.Our estimated Lorentz factor of γ ～ 9-13 for quasars,γ ～ 7-11for galaxies and γ ～ 4-9 for BL Lac objects indicates that BL Lacs have the lowest range of Lorentz factors.
Energy Technology Data Exchange (ETDEWEB)
Liang, Yun-Feng; Zhou, Bei; He, Hao-Ning; Fan, Yi-Zhong; Wei, Da-Ming [Key laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Tam, Pak-Hin Thomas, E-mail: phtam@phys.nthu.edu.tw [Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China)
2014-02-01
GRB 130821A was detected by Fermi-GBM/LAT, Konus-WIND, SPI-ACS/INTEGRAL, RHESSI and Mars Odyssey-HEND. Although the data of GRB 130821A are very limited, we show in this work that the high energy γ-ray emission (i.e., above 100 MeV) alone imposes tight constraint on the density profile of the circum-burst medium as well as the initial Lorentz factor of the outflow. The temporal behavior of the high energy γ-ray emission is consistent with the forward shock synchrotron radiation model, and the circum-burst medium likely has a constant-density profile. The Lorentz factor is about a few hundred, similar to other bright GRBs.
Why is High Energy Physics Lorentz Invariant?
Afshordi, Niayesh
2015-01-01
Despite the tremendous empirical success of equivalence principle, there are several theoretical motivations for existence of a preferred reference frame (or aether) in a consistent theory of quantum gravity. However, if quantum gravity had a preferred reference frame, why would high energy processes enjoy such a high degree of Lorentz symmetry? While this is often considered as an argument against aether, here I provide three independent arguments for why perturbative unitarity (or weak coupling) of the Lorentz-violating effective field theories put stringent constraints on possible observable violations of Lorentz symmetry at high energies. In particular, the interaction with the scalar graviton in a consistent low-energy theory of gravity and a (radiatively and dynamically) stable cosmological framework, leads to these constraints. The violation (quantified by the relative difference in maximum speed of propagation) is limited to $\\lesssim 10^{-10} E({\\rm eV})^{-4}$ (superseding all current empirical bound...
What Governs Lorentz Factors of Jet Components in Blazars?
Indian Academy of Sciences (India)
Xinwu Cao; Bo Chai; Ming Zhou; Minfeng Gu
2014-09-01
We use a sample of radio-loud Active Galactic Nuclei (AGNs) with measured black hole masses to explore the jet formation mechanisms in these sources. We find a significant correlation between black hole mass and the bulk Lorentz factor of the jet components for this sample, while no significant correlation is present between the bulk Lorentz factor and the Eddington ratio. Recent investigations suggested that the most super-massive black holes in elliptical galaxies have on average higher spins than the black holes in spiral galaxies. The correlation between black hole mass and bulk Lorentz factor of the jet components found in this work implies that the motion velocity of the jet components is probably governed by the black hole spin. The faster moving jets are magnetically accelerated by the magnetic fields threading the horizon of more rapidly rotating black holes.
High Energy Astrophysics Tests of Lorentz Invariance Violation
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.
Wang, Yuan-Zhu; Wang, Hao; Zhang, Shuai; Liang, Yun-Feng; Jin, Zhi-Ping; He, Hao-Ning; Liao, Neng-Hui; Fan, Yi-Zhong; Wei, Da-Ming
2017-02-01
GRB 160625B is an extremely bright outburst with well-monitored afterglow emission. The geometry-corrected energy is high, up to ˜5.2 × 1052 erg or even ˜8 × 1052 erg, rendering it the most energetic GRB prompt emission recorded so far. We analyzed the time-resolved spectra of the prompt emission and found that in some intervals there were likely thermal-radiation components and the high energy emission was characterized by significant cutoff. The bulk Lorentz factors of the outflow material are estimated accordingly. We found out that the Lorentz factors derived in the thermal-radiation model are consistent with the luminosity-Lorentz factor correlation found in other bursts, as well as in GRB 090902B for the time-resolved thermal-radiation components, while the spectral cutoff model yields much lower Lorentz factors that are in tension with the constraints set by the electron pair Compton scattering process. We then suggest that these spectral cutoffs are more likely related to the particle acceleration process and that one should be careful in estimating the Lorentz factors if the spectrum cuts at a rather low energy (e.g., ˜tens of MeV). The nature of the central engine has also been discussed, and a stellar-mass black hole is favored.
Dynamic-structure-factor measurements on a model Lorentz gas
Egelstaff, P. A.; Eder, O. J.; Glaser, W.; Polo, J.; Renker, B.; Soper, A. K.
1990-02-01
A model system for the Lorentz gas can be made [Eder, Chen, and Egelstaff, Proc. Phys. Soc. London 89, 833 (1966); McPherson and Egelstaff, Can. J. Phys. 58, 289 (1980)] by mixing small quantities of hydrogen with an argon host. For neutron-scattering experiments the large H-to-Ar cross section ratio (~200) makes the argon relatively invisible. Dynamic-structure-factor [S(Q,ω) for H2] measurements at room temperature have been made on this system using the IN4 spectrometer at the Institute Laue Langevin, Grenoble, France. Argon densities between 1.9 and 10.5 atoms/nm3 were used for 0.4
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.
Wang, Yuan-Zhu; Zhang, Shuai; Liang, Yun-Feng; Jin, Zhi-Ping; He, Hao-Ning; Liao, Neng-Hui; Fan, Yi-Zhong; Wei, Da-Ming
2016-01-01
GRB 160625B is an extremely-bright outburst with well-monitored afterglow emission. The geometry-corrected energy is high up to $\\sim 5.2\\times10^{52}$ erg or even $\\sim 8\\times 10^{52}$ erg, rendering it the most energetic GRB prompt emission recorded so far. We analyzed the time-resolved spectra of the prompt emission and found that in some intervals there were likely thermal-radiation components and the high energy emission were characterized by significant cutoff. The bulk Lorentz factors of the outflow material are estimated accordingly. We found out that the Lorentz factors derived in the thermal-radiation model are consistent with the luminosity-Lorentz factor correlation found in other bursts as well as in GRB 090902B for the time-resolved thermal-radiation components. While the spectral cutoff model yields much lower Lorentz factors that are in tension with the constraints set by the electron pair Compoton scattering process. We then suggest that these spectral cutoffs are more likely related to the ...
High Energy Astrophysics Tests of Lorentz Invariance and Quantum Gravity Models
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.
Lamb, Gavin P
2016-01-01
Short gamma-ray bursts (GRBs) are believed to be produced by relativistic jets from mergers of neutron stars (NS) and/or black holes (BH). If the Lorentz factors $\\Gamma$ of jets from compact stellar mergers follow a similar power-law distribution as those observed for other high energy astrophysical phenomena (e.g. blazars, AGN), the population of jets would be dominated by low-$\\Gamma$ outflow. These jets will not produce GRB (i.e. the prompt gamma-rays), but their jet energy will be released as optical and radio transients when they collide into the ambient medium. By using simple Monte Carlo simulations, we study the properties of such transient events. Approximately $78 \\%$ of merger jets within 300 Mpc distance will result in a failed GRB if the jet Lorentz factor follows a power-law distribution of index $-1.75$. Optical transients associated with such failed GRBs will have rather broad distributions of the characteristics: the light curve peaks $t_p \\sim 0.1-10$ days after a merger with a peak flux $m...
Lorentz factor distribution of blazars from the optical Fundamental plane of black hole activity
Saikia, Payaswini; Falcke, Heino
2016-01-01
Blazar radiation is dominated by a relativistic jet which can be modeled at first approximation using just two intrinsic parameters - the Lorentz factor $\\Gamma$ and the viewing angle $\\theta$. Blazar jet observations are often beamed due to relativistic effects, complicating the understanding of these intrinsic properties. The most common way to estimate blazar Lorentz factors needs the estimation of apparent jet speeds and Doppler beaming factors. We present a new and independent method of constructing the blazar Lorentz factor distribution, using the optical fundamental plane of black hole activity. The optical fundamental plane is a plane stretched out by both the supermassive black holes and the X-ray binaries, in the 3D space provided by their [OIII] line luminosity, radio luminosity and black hole mass. We use the intrinsic radio luminosity obtained from the optical fundamental plane to constrain the boosting parameters of the VLBA Imaging and Polarimetry Survey (VIPS) blazar sample. We find a blazar b...
Completing Lorentz violating massive gravity at high energies
Blas, Diego
2015-01-01
Theories with massive gravitons are interesting for a variety of physical applications, ranging from cosmological phenomena to holographic modeling of condensed matter systems. To date, they have been formulated as effective field theories with a cutoff proportional to a positive power of the graviton mass m_g and much smaller than that of the massless theory (M_P ~ 10^19 GeV in the case of general relativity). In this paper we present an ultraviolet completion for massive gravity valid up to a high energy scale independent of the graviton mass. The construction is based on the existence of a preferred time foliation combined with spontaneous condensation of vector fields. The perturbations of these fields are massive and below their mass the theory reduces to a model of Lorentz violating massive gravity. The latter theory possesses instantaneous modes whose consistent quantization we discuss in detail. We briefly study some modifications to gravitational phenomenology at low-energies. The homogeneous cosmolo...
Beam propagation factors and kurtosis parameters of a Lorentz-Gauss vortex beam.
Zhou, Guoquan
2014-06-01
Based on the second-order and the higher-order moments, analytical expressions for the beam propagation factors of a Lorentz-Gauss vortex beam with l=1 have been derived, and analytical propagation expressions for the kurtosis parameters of a Lorentz-Gauss vortex beam with l=1 through a paraxial and real ABCD optical system have also been presented. The M² factor is determined by the parameters a and b and decreases with increasing the parameter a or b. The M² factor is validated to be larger than 2. The kurtosis parameters depend on the diffraction-free ranges of the Lorentz part, the parameters a and b, and the ratio A/B. The kurtosis parameters of a Lorentz-Gauss vortex beam propagating in free space are demonstrated in different reference planes. In the far field, the kurtosis parameter K decreases with increasing one of the parameters a and b. Upon propagation, the kurtosis parameter K first decreases, then increases, and finally tends to a saturated value. In any case, the kurtosis parameter K is larger than 2. This research is beneficial to optical trapping, guiding, and manipulation of microscopic particles and atoms using Lorentz-Gauss vortex beams.
Strongly Enhanced Effects of Lorentz-Symmetry Violation in Yb$^+$ and Highly Charged Ions
Safronova, M S
2016-01-01
A Lorentz-symmetry test with Ca$^+$ ions demonstrated the potential of using quantum information inspired technology for tests of fundamental physics. A systematic study of atomic-system sensitivities to Lorentz violation identified the ytterbium ion as an ideal system with high sensitivity as well as excellent experimental controllability. A test of Lorentz-violating physics in the electron-photon sector with Yb$^+$ ions has the potential to reach levels of 10$^{-23}$, five orders of magnitude more sensitive than the current best bounds. Similar sensitivities may be also reached with highly charged ions.
High-Energy Nuclear Physics with Lorentz Symmetry Violation
González-Mestres, L
1997-01-01
If textbook Lorentz invariance is actually a property of the equations describing a sector of the excitations of vacuum above some critical distance scale, several sectors of matter with different critical speeds in vacuum can coexist and an absolute rest frame (the vacuum rest frame) may exist without contradicting the apparent Lorentz invariance felt by "ordinary" particles (particles with critical speed in vacuum equal to $c$ , the speed of light). Sectorial Lorentz invariance, reflected by the fact that all particles of a given dynamical sector have the same critical speed in vacuum, will then be an expression of a fundamental sectorial symmetry (e.g. preonic grand unification or extended supersymmetry) protecting a parameter of the equations of motion. Furthermore, the sectorial Lorentz symmetry may be only a low-energy limit, in the same way as the relation $\\omega $ (frequency) = $c_s$ (speed of sound) $k$ (wave vector) holds for low-energy phonons in a crystal. In this context, phenomena such as the a...
Ejection Lorentz Factor and Radiation Location of X-ray Flares
Mu, Hui-Jun; Xi, Shao-Qiang; Lin, Ting-Ting; Wang, Yuan-Zhu; Liang, Yun-Feng; Lv, Lian-Zhong; Zhang, Jin; Liang, En-Wei
2016-01-01
We present time-resolved spectral analysis of the steep decay segments of 29 bright X-ray flares of gamma-ray bursts (GRBs) observed with the Swift/X-ray telescope, and model their lightcurves and spectral index evolution behaviors with the curvature effect model. Our results show that the observed rapid flux decay and strong spectral index evolution with time can be well fit with this model, and the derived characteristic timescales ($t_c$) are in the range of $33\\sim 264$ seconds. Using an empirical relation between the peak luminosity and the Lorentz factor derived from the prompt gamma-rays, we estimate the Lorentz factors of the flares ($\\Gamma_{\\rm X}$). We obtain $\\Gamma_{\\rm X}=17\\sim 87$ with a median value of $52$, which is smaller than the initial Lorentz factors of prompt gamma-ray fireballs. With the derived $t_c$ and $\\Gamma_{\\rm X}$, we constrain the radiating regions of 13 X-ray flares, yielding $R_{\\rm X}=(0.2\\sim 1.1)\\times 10^{16}$ cm, which are smaller than the radii of the afterglow fireb...
Vuillaume, Thomas; Henri, Gilles
2014-01-01
AGNs jets are known to display relativistic motion on parsec scales but the accelerating mechanism as well as the exact bulk Lorentz factor of the flow are still a matter of discussion. Under certain assumptions, a plasma can be accelerated to relativistic speeds through the Compton rocket effect. Here, we study this effect and the resulting bulk Lorentz factor in the complex environment of an AGN including various external sources. This is the proceedings to the IAU Symposium 313.
Institute of Scientific and Technical Information of China (English)
Zhang Fu-Wen; Qin Yi-Ping
2005-01-01
Time profiles of many gamma-ray bursts consist of distinct pulses, which provides a possibility of characterizing the temporal structure of these bursts. We employ a simple model of highly symmetric fireballs to analyse the effect of the expansion speed on the light curve arising from different forms of local pulses. The relationship between the ratio r of the FWHM width of the rising phase of the light curve to that of the decaying phase and the Lorentz factor is investigated. The analysis shows that, when the rest frame radiation form is ignored, temporal profiles of the light curve arising from pulses of fireballs will not be affected by the expansion speed (that is, r is almost a constant) as long as the fireball expands relativistically. When the rest frame radiation form is taken into account, there will be a break in the curves of r - log Γ. The location of the break depends mainly on the adopted value of the rest frame peak frequency v0,p. One would reach almost the same result when a jet is considered. In addition, we utilize a sample of 48individual GRB pulses to check the relationship between the ratio r and the expansion speed Γ. We find no significant correlation between them, and this is consistent with the theoretical analysis.
Constraints on the bulk Lorentz factor of Gamma-Ray Burst jets from Fermi/LAT upper limits
Nava, L; Longo, F; Celotti, A; Omodei, N; Vianello, G; Bissaldi, E; Piran, T
2016-01-01
It is largely recognized that Gamma-Ray Burst (GRB) jets involve ultra-relativistic motion. However, the value of the Lorentz factor Gamma_0 is still not clear and only lower limits are known for most bursts. We suggest here a new method to obtain upper limits on Gamma_0. The early high-energy synchrotron afterglow flux depends strongly on Gamma_0. Upper limits on GeV emission therefore provide uppers limit on Gamma_0. Applying this method to 190 Fermi GRBs that have not been detected by the Fermi-LAT we place upper limits on the high-energy afterglow flux, and in turn on Gamma_0. For bursts at a typical redshift z=2, we find values of the order of 200 (and above) for a homogeneous density medium, and in the range 100-400 for a wind-like medium. These upper limits are consistent with (and are very close to) lower limits and direct estimates inferred using other methods, suggesting that the typical Lorentz factors of GRB jets are of order a few hundred.
Constraints on the bulk Lorentz factor of gamma-ray burst jets from Fermi /LAT upper limits
Nava, L.; Desiante, R.; Longo, F.; Celotti, A.; Omodei, N.; Vianello, G.; Bissaldi, E.; Piran, T.
2017-02-01
It is largely recognized that Gamma-Ray Burst (GRB) jets involve ultra-relativistic motion. However, the value of the Lorentz factor Gamma_0 is still not clear and only lower limits are known for most bursts. We suggest here a new method to obtain upper limits on Gamma_0. The early high-energy synchrotron afterglow flux depends strongly on Gamma_0. Upper limits on GeV emission therefore provide uppers limit on Gamma_0. Applying this method to 190 Fermi GRBs that have not been detected by the Fermi-LAT we place upper limits on the high-energy afterglow flux, and in turn on Gamma_0. For bursts at a typical redshift z=2, we find values of the order of 200 (and above) for a homogeneous density medium, and in the range 100-400 for a wind-like medium. These upper limits are consistent with (and are very close to) lower limits and direct estimates inferred using other methods, suggesting that the typical Lorentz factors of GRB jets are of order a few hundred.
The GRB afterglow onset observed by REM: fireball Lorentz factor and afterglow fluence
Malesani, Daniele; Vergani, Susanna; Covino, Stefano
2007-01-01
We report observations of the early light curves of GRB 060418 and GRB 060607A, carried out with the pink robotic telescope REM. A clear peak is detected for both events, which is interpreted as the onset of the afterglow, that is the time at which the fireball starts decelerating. This detection allows to directly measure the initial fireball Lorentz factor, which was found to be Gamma_0 ~ 400 for both events, fully confirming the ultrarelativistic nature of gamma-ray burst fireballs. Sampling the light curve before the peak also allows to compute the bolometric fluence of the afterglow, which is 16% of the prompt one in the case of GRB 060418.
Ultra-High Energy Astrophysical Neutrino Detection, and the Search for Lorentz Invariance Violations
Hanson, J C
2016-01-01
A growing class of ultra-high energy neutrino (UHE-nu) observatories based on the Askaryan effect and Antarctic ice is able to search for Lorentz invariance violation (LIV). The ARA, ARIANNA, ANITA and EVA collaborations have the power to constrain the Standard Model Extension (SME) by measuring the flux and energy distribution of neutrinos created through the GZK process. The future expansion of ARA, at the South Pole, pushes the discovery potential further.
Planck-scale Lorentz violation constrained by ultra-high-energy cosmic rays
Energy Technology Data Exchange (ETDEWEB)
Maccione, L. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Univ. Hamburg, II. Inst. fuer Theoretische Physik (Germany); Taylor, A.M. [Max-Planck-Inst. fuer Kernphysik, Heidelberg (Germany); Mattingly, D.M.; Liberati, S. [Scuola Internazionale Superiore di Studi Avanzati SISSA, Trieste (Italy); Istituto Nazionale di Fisica Nucleare INFN, Sezione di Trieste (Italy)
2009-09-15
We investigate the consequences of higher dimension Lorentz violating, CPT even kinetic operators that couple standard model fields to a non-zero vector field in an Effective Field Theory framework. Comparing the ultra-high energy cosmic ray spectrum reconstructed in the presence of such terms with data from the Pierre Auger observatory allows us to establish two sided bounds on the coefficients of the mass dimension five and six operators for the proton and pion. Our bounds imply that for both protons and pions, the energy scale of Lorentz symmetry breaking must be well above the Planck scale. In particular, the dimension five operators are constrained at the level of 10{sup -3}M{sup -1}{sub Planck}. The magnitude of the dimension six proton coefficient is bounded at the level of 10{sup -6}M{sup -2}{sub Planck} except in a narrow range where the pion and proton coefficients are both negative and nearly equal. In this small area, the magnitude of the dimension six proton coefficient must only be below 10{sup -3}M{sup -2}{sub Planck}. Constraints on the dimension six pion coefficient are found to be much weaker, but still below M{sup -2}{sub Planck}. (orig.)
High harmonic interferometry of the Lorentz force in strong mid-infrared laser fields
Pisanty, Emilio; Galloway, Benjamin R; Durfee, Charles G; Kapteyn, Henry C; Murnane, Margaret M; Ivanov, Misha
2016-01-01
The interaction of intense mid-infrared laser fields with atoms and molecules leads to a range of new opportunities, from the production of bright, coherent radiation in the soft x-ray range to imaging molecular structures and dynamics with attosecond temporal and sub-angstrom spatial resolution. However, all these effects, which rely on laser-driven recollision of an electron removed by the strong laser field and the parent ion, suffer from the rapidly increasing role of the magnetic field component of the driving pulse: the associated Lorentz force pushes the electrons off course in their excursion and suppresses all recollision-based processes, including high harmonic generation, elastic and inelastic scattering. Here we show how the use of two non-collinear beams with opposite circular polarizations produces a forwards ellipticity which can be used to monitor, control, and cancel the effect of the Lorentz force. This arrangement can thus be used to re-enable recollision-based phenomena in regimes beyond t...
Lorentz factor - Beaming corrected energy/luminosity correlations and GRB central engine models
Yi, Shuang-Xi; Lei, Wei-Hua; Zhang, Bing; Dai, Zi-Gao; Wu, Xue-Feng; Liang, En-Wei
2017-03-01
We work on a GRB sample whose initial Lorentz factors (Γ0) are constrained by the afterglow onset method and the jet opening angles (θj) are determined by the jet break time. We confirm the Γ0-Eγ,iso correlation by Liang et al. (2010), and the Γ0-Lγ,iso correlation by Lü et al. (2012). Furthermore, we find correlations between Γ0 and the beaming corrected γ-ray energy (Eγ) and mean γ-ray luminosity (Lγ). By also including the kinetic energy of the afterglow, we find rough correlations (with larger scatter) between Γ0 and the total (γ-ray plus kinetic) energy and the total mean luminosity, both for isotropic values and beaming corrected values: these correlations allow us to test the data with GRB central engine models. Limiting our sample to the GRBs that likely have a black hole central engine, we compare the data with theoretical predictions of two types of jet launching mechanisms from BHs, i.e. the non-magnetized ν ν bar -annihilation mechanism, and the strongly magnetized Blandford-Znajek (BZ) mechanism. We find that the data are more consistent with the latter mechanism, and discuss the implications of our findings for GRB jet composition.
Lorentz invariance violation and chemical composition of ultra high energy cosmic rays
Energy Technology Data Exchange (ETDEWEB)
Saveliev, Andrey; Sigl, Guenter [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; Maccione, Luca [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group
2010-12-15
Motivated by experimental indications of a significant presence of heavy nuclei in the cosmic ray flux at ultra high energies (>or similar 10{sup 19} eV), we consider the effects of Planck scale suppressed Lorentz Invariance Violation (LIV) on the propagation of cosmic ray nuclei. In particular we focus on LIV effects on the photodisintegration of nuclei onto the background radiation fields. After a general discussion of the behavior of the relevant quantities, we apply our formalism to a simplified model where the LIV parameters of the various nuclei are assumed to kinematically result from a single LIV parameter for the constituent nucleons, {eta}, and we derive constraints on {eta}. Assuming a nucleus of a particular species to be actually present at 10{sup 20} eV the following constraints can be placed: -3 x 10{sup -2}
Deviations from Fick's law in Lorentz gases
Lowe, C.P.; Frenkel, D.; Hoef, M.A. van der
1997-01-01
We have calculated the self-dynamic structure factorF(k,t) for tagged particle motion in hopping Lorentz gases. We find evidence that, even at long times, the probability distribution function for the displacement of the particles is highly non-Gaussian. At very small values of the wave vector this
Deviations from Fick's law in Lorentz gases
Lowe, C.P.; Frenkel, D.; Hoef, M.A. van der
1997-01-01
We have calculated the self-dynamic structure factorF(k,t) for tagged particle motion in hopping Lorentz gases. We find evidence that, even at long times, the probability distribution function for the displacement of the particles is highly non-Gaussian. At very small values of the wave vector this
Lifshitz-scaling to Lorentz-violating high derivative operator and gamma-ray busts
Passos, E; Anacleto, M A; Brito, F A; Wotzasek, C; Zarro, C A D
2016-01-01
In this work we have used a Hovrava-Lifshitz scaling to rewrite a Lorentz-violating higher-order derivative electrodynamics controlled by a background four-vector $n_{\\mu}$. The photon propagator was obtained and we have analyzed the dispersion relation and the observational results of gamma-ray burst (GRB) experiments were used. The limits of the critical exponent were discussed in the light of the GRB data and the physical implications were compared with the current GRB-Lorentz-invariance-violation literature. We show that the bound for the Lorentz-violating coupling for dimension-six operators, obtained from a Hovrava-Lifshitz scaling, is eight orders of magnitude better than the result found without considering a Hovrava-Lifshitz scaling, also this bound is nearby one, which is expected to be relevant phenomenologically.
Vacuum Cherenkov Radiation In Quantum Electrodynamics With High-Energy Lorentz Violation
Anselmi, Damiano
2011-01-01
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_{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_{L} (with preserved CPT invariance) can be smaller than the Planck scale, actually as small as 10^{14}-10^{15} GeV. Our model also predicts the Cherenkov radiation of neutral particles.
A precision test of Lorentz invariance using room-temperature high-finesse optical resonators
Energy Technology Data Exchange (ETDEWEB)
Eisele, Christian
2009-10-28
necessary, since a tilt of the resonators with respect to the local direction of gravitation leads to a shift of the resonance frequencies. Finally, servo systems have been implemented to stabilize the optical power circulating in the resonators and the temperature of the setup. The complete experiment can be actively rotated by means of an high precision air bearing rotation table, which allows for a considerable increase of the rate of data taking as compared to a stationary system. This allows for a comparatively fast reduction of statistical errors. Another advantage of the active rotation is the relaxation of stability demands for long timescales. A high frequency stability is needed on a timescale of half a rotation, here {approx} 45 s, while for stationary systems it would be 12 hours since one has to rely on the rotation of the earth. With the setup just described we have performed measurements between march 2008 and may 2009 yielding {approx} 135000 rotations distributed over the entire timespan. This data was analyzed according to two different test theories, the Robertson-Mansouri-Sexl theory (RMS) and the Standard Modell extension (SME). Within the RMS theory a single parameter combination ({delta} - {beta} + 1/2) describes a possible anisotropy. For an isotropic speed of light it equals zero. We determined an upper limit of ({delta} - {beta} + 1/2) {<=} 8 . 10{sup -12} corresponding to a relative anisotropy of the speed of light below (1)/(2) vertical stroke {delta}c({pi}/2)/c vertical stroke {<=} 6 . 10{sup -18} (1{sigma} bounds). This value is more than one order of magnitude smaller than the values published so far. Within the framework of the SME we could determine 8 parameters describing a possible violation of the Lorentz invariance by photons. Upper limits for these parameters could be improved considerably compared to the experimental predecessor of the setup and to the values determined by other groups. Parts of this thesis have already been published
A precision test of Lorentz invariance using room-temperature high-finesse optical resonators
Energy Technology Data Exchange (ETDEWEB)
Eisele, Christian
2009-10-28
necessary, since a tilt of the resonators with respect to the local direction of gravitation leads to a shift of the resonance frequencies. Finally, servo systems have been implemented to stabilize the optical power circulating in the resonators and the temperature of the setup. The complete experiment can be actively rotated by means of an high precision air bearing rotation table, which allows for a considerable increase of the rate of data taking as compared to a stationary system. This allows for a comparatively fast reduction of statistical errors. Another advantage of the active rotation is the relaxation of stability demands for long timescales. A high frequency stability is needed on a timescale of half a rotation, here {approx} 45 s, while for stationary systems it would be 12 hours since one has to rely on the rotation of the earth. With the setup just described we have performed measurements between march 2008 and may 2009 yielding {approx} 135000 rotations distributed over the entire timespan. This data was analyzed according to two different test theories, the Robertson-Mansouri-Sexl theory (RMS) and the Standard Modell extension (SME). Within the RMS theory a single parameter combination ({delta} - {beta} + 1/2) describes a possible anisotropy. For an isotropic speed of light it equals zero. We determined an upper limit of ({delta} - {beta} + 1/2) {<=} 8 . 10{sup -12} corresponding to a relative anisotropy of the speed of light below (1)/(2) vertical stroke {delta}c({pi}/2)/c vertical stroke {<=} 6 . 10{sup -18} (1{sigma} bounds). This value is more than one order of magnitude smaller than the values published so far. Within the framework of the SME we could determine 8 parameters describing a possible violation of the Lorentz invariance by photons. Upper limits for these parameters could be improved considerably compared to the experimental predecessor of the setup and to the values determined by other groups. Parts of this thesis have already been published
Stecker, F W
2003-01-01
Observations of the multi-TeV spectra of the nearby BL objects Mkn 421 and Mkn 501 exhibit the high energy cutoffs predicted to be the result of intergalactic annihilation interactions, primarily with infrared photons having a flux level as determined by various astronomical observations. After correction for this absorption effect, the derived intrinsic spectra of these multi-TeV sources can be explained within the framework of simple synchrotron self-Compton emission models. Stecker and Glashow have shown that the existence of such annihilations via electron-positron pair production interactions up to an energy of 20 TeV puts strong constraints on Lorentz invariance violation. Such constraints have important implications for Lorentz invariance violating (LIV) quantum gravity models as well as LIV models involving large extra dimensions. We also discuss the implications of observations of high energy gamma-rays from the Crab Nebula on constraining quantum gravity models.
Koga, James
2004-10-01
Usually the motion of an electron under the influence of electromagnetic fields is influenced to a small extent by radiation damping. With the advent of high power high irradiance lasers it has become possible to generate focused laser irradiances where electrons interacting with the laser become highly relativistic over very short time and spatial scales. By focusing petawatt class lasers to very small spot sizes the amount of radiation emitted by electrons can become very large. Resultingly, the damping of the electron motion by the emission of this radiation can become large. In order to study this problem a code is written to solve a set of equations describing the evolution of a strong electromagnetic wave interacting with a single electron. Usually the equation of motion of an electron including radiation damping under the influence of electromagnetic fields is derived from the Lorentz-Dirac equation treating the damping as a perturbation. We use this equation to integrate forward in time and use the Lorentz-Dirac equation to integrate backward in time. We show that for very short wavelength electromagnetic radiation deep in the quantum regime at high irradiances differences between the perturbation equation and Lorentz-Dirac can be seen. However, for electron motion in the classical regime the differences are negligible. For electron motion in the classical regime the first order damping equation is found to be very adequate.
Ultra high energy photons as probes of Lorentz symmetry violations in stringy space-time foam models
Energy Technology Data Exchange (ETDEWEB)
Maccione, Luca [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group; Liberati, Stefano [SISSA, Trieste (Italy); INFN, Trieste (Italy); Sigl, Guenter [Hamburg Univ. (Germany). Inst. fuer Theoretische Physik
2010-03-15
The time delays between gamma-rays of different energies from extragalactic sources have often been used to probe quantum gravity models in which Lorentz symmetry is violated. It has been claimed that these time delays can be explained by or at least put the strongest available constraints on quantum gravity scenarios that cannot be cast within an effective field theory framework, such as the space-time foam, D-brane model. Here we show that this model would predict too many photons in the ultra-high energy cosmic ray flux to be consistent with observations. The resulting constraints on the space-time foam model are much stronger than limits from time delays and allow for Lorentz violations effects way too small for explaining the observed time delays. (orig.)
Lorentz violation naturalness revisited
Belenchia, Alessio; Liberati, Stefano
2016-01-01
We revisit here the naturalness problem of Lorentz invariance violations on a simple toy model of a scalar field coupled to a fermion field via a Yukawa interaction. We first review some well-known results concerning the low-energy percolation of Lorentz violation from high energies, presenting some details of the analysis not explicitly discussed in the literature and discussing some previously unnoticed subtleties. We then show how a separation between the scale of validity of the effective field theory and that one of Lorentz invariance violations can hinder this low-energy percolation. While such protection mechanism was previously considered in the literature, we provide here a simple illustration of how it works and of its general features. Finally, we consider a case in which dissipation is present, showing that the dissipative behaviour does not percolate generically to lower mass dimension operators albeit dispersion does. Moreover, we show that a scale separation can protect from unsuppressed low-en...
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.
Fractional Fourier transform of Lorentz beams
Institute of Scientific and Technical Information of China (English)
Zhou Guo-Quan
2009-01-01
This paper introduces Lorentz beams to describe certain laser sources that produce highly divergent fields. The fractional Fourier transform (FRFT) is applied to treat the propagation of Lorentz beams. Based on the definition of convolution and the convolution theorem of the Fourier transform, an analytical expression for a Lorentz beam passing through a FRFT system has been derived. By using the derived formula, the properties of a Lorentz beam in the FRFT plane are illustrated numerically.
Variation of bulk Lorentz factor in AGN jets due to Compton rocket in a complex photon field
Vuillaume, Thomas; Petrucci, Pierre-Olivier
2015-01-01
Radio-loud active galactic nuclei are among the most powerful objects in the universe. In these objects, most of the emission comes from relativistic jets getting their power from the accretion of matter onto supermassive black holes. However, despite the number of studies, a jet's acceleration to relativistic speeds is still poorly understood. It is widely known that jets contain relativistic particles that emit radiation through several physical processes, one of them being the inverse Compton scattering of photons coming from external sources. In the case of a plasma composed of electrons and positrons continuously heated by the turbulence, inverse Compton scattering can lead to relativistic bulk motions through the Compton rocket effect. We investigate this process and compute the resulting bulk Lorentz factor in the complex photon field of an AGN composed of several external photon sources. We consider various sources here: the accretion disk, the dusty torus, and the broad line region. We take their geo...
Calculation of the astrophysical S-factor S_12 with the Lorentz integral transform
Deflorian, Sergio; Leidemann, Winfried
2016-01-01
The LIT approach is tested for the calculation of astrophysical S-factors. As an example the S-factor of the reaction 2H(p,gamma)3He is considered. It is discussed that a sufficiently high density of LIT states at low energies is necessary for a precise determination of S-factors. In particular it is shown that the hyperspherical basis is not very well suited for such a calculation and that a different basis system is much more advantageous. A comparison of LIT results with calculations, where continuum wave functions are explicitly used, shows that the LIT approach leads to reliable results. It is also shown how an error estimate of the LIT inversion can be obtained.
Direct observation of domain walls in NiFe films using high-resolution Lorentz microscopy
Wong, Bunsen Y.; Laughlin, David E.
1996-04-01
A novel approach to observe the interaction between magnetic domain wall and nanoscale microstructural features is demonstrated. The method is based on Focault mode Lorentz microscopy and utilizes a Gatan energy image filter to provide additional magnification. A postexperimental image processing technique was applied to separate lattice diffraction from that induced by magnetic domains. The effect of NiFe thickness on the width of a 180° Néel wall has been studied. It was found that the thickness dependence has a similar profile to the theoretically predicted trend but the actual wall thickness is smaller than the calculated values.
Hascoët, Romain; Beloborodov, Andrei M
2015-01-01
Fermi satellite discovered that cosmological gamma-ray bursts (GRBs) are accompanied by long GeV flashes. In two GRBs, an optical counterpart of the GeV flash has been detected. Recent work suggests that the GeV+optical flash is emitted by the external blast wave from the explosion in a medium loaded with copious $e^\\pm$ pairs. The full light curve of the flash is predicted by a first-principle radiative transfer simulation and can be tested against observations. Here we examine a sample of 7 bursts with best GeV+optical data and test the model. We find that the observed light curves are in agreement with the theoretical predictions and allow us to measure three parameters for each burst: the Lorentz factor of the explosion, its isotropic kinetic energy, and the external density. With one possible exception of GRB 090510 (which is the only short burst in the sample) the ambient medium is consistent with a wind from a Wolf-Rayet progenitor. The wind density parameter $A=\\rho r^2$ varies in the sample around $1...
Mitra, A N
1999-01-01
The Markov-Yukawa Transversality Principle (TP) on a 2-body Bethe-Salpeter kernel is formulated on a covariant Null Plane (NP) to reconstruct the 4D BS wave function for 2 fermion quarks in terms of 3D entities that satisfy a 3D BSE. This result is a null-plane counterpart of a similar interconnection for the 2-body BS wave functions found earlier by imposing the TP covariantly in the instantaneous rest frame (termed CIA) of the composite. This ``TP-NP'' formulation yields a 3D BSE which is formally identical in structure to its 3D CIA form, thus fully preserving the spectral results of CIA. More importantly, 4D quark-loop integrals are now free from time-like momentum anomalies caused by the product of gaussian wave functions in their integrands, while a simple prescription of `Lorentz completion' yields a manifestly L-invariant amplitude. This is illustrated for the pion form factor which is worked out with full QED gauge-invariance and shows a $k^{-2}$ behaviour at large $k^2$. This method is also compared...
Lorentz violation naturalness revisited
Energy Technology Data Exchange (ETDEWEB)
Belenchia, Alessio; Gambassi, Andrea; Liberati, Stefano [SISSA - International School for Advanced Studies, via Bonomea 265, 34136 Trieste (Italy); INFN, Sezione di Trieste, via Valerio 2, 34127 Trieste (Italy)
2016-06-08
We revisit here the naturalness problem of Lorentz invariance violations on a simple toy model of a scalar field coupled to a fermion field via a Yukawa interaction. We first review some well-known results concerning the low-energy percolation of Lorentz violation from high energies, presenting some details of the analysis not explicitly discussed in the literature and discussing some previously unnoticed subtleties. We then show how a separation between the scale of validity of the effective field theory and that one of Lorentz invariance violations can hinder this low-energy percolation. While such protection mechanism was previously considered in the literature, we provide here a simple illustration of how it works and of its general features. Finally, we consider a case in which dissipation is present, showing that the dissipative behaviour does not percolate generically to lower mass dimension operators albeit dispersion does. Moreover, we show that a scale separation can protect from unsuppressed low-energy percolation also in this case.
Peér, A; Wijers, R A M J; Mészáros, P; Rees, M J; Pe'er, Asaf; Ryde, Felix; Wijers, Ralph A.M.J.; M\\'esz\\'aros, Peter; Rees, Martin J.
2007-01-01
In recent years there is increasing evidence for a thermal component in the gamma- and X-ray spectrum of the prompt emission phase in gamma-ray bursts. The temperature and flux of the thermal component show a characteristic break in the temporal behavior after few seconds. We show here, that measurements of the temperature and flux of the thermal component at early times (before the break) allow the determination of the values of two of the least restricted fireball model parameters: the size at the base of the flow and the outflow bulk Lorentz factor. Relying on the thermal emission component only, this measurement is insensitive to the inherent uncertainties of previous estimates of the bulk motion Lorentz factor. We give specific examples of the use of this method: for GRB970828 at redshift z=0.9578, we show that the physical size at the base of the flow is r_0 = (3.3+-2.1)*10^8 cm and the Lorentz factor of the flow is \\Gamma = 305+-28, and for GRB990510 at z=1.619, r_0=(1.9+-2.0)*10^8 cm and \\Gamma=384+-7...
Harada, Ken
2013-06-01
Lorentz microscopy has opened the door to observing a single quantized magnetic flux line (i.e. a vortex) and its dynamic behavior inside a superconductor in real time. It resulted from the efforts of Dr Akira Tonomura and his collaborators, who developed a field emission electron microscope and advanced the technologies used for visualizing vortices (e.g. a low-temperature specimen stage and a magnetic-field application system). They used a 1-MV field emission transmission electron microscope with an electron beam that can penetrate thick specimens of high-temperature superconductors (Bi2Sr2CaCu2O8+δ and YB2C3O7-δ) to reveal the flux-line features inside materials and their interactions with defects. This memorial paper reviews the results of research in the area of vortex matter physics.
Asymptotic behavior of Lorentz violation on orbifolds
Uekusa, Nobuhiro
2010-01-01
Momentum dependence of quantum corrections with higher-dimensional Lorentz violation is examined in electrodynamics on orbifolds. It is shown that effects of the Lorentz violation are not decoupled at high energy scales. Despite the loss of the higher-dimensional Lorentz invariance, a higher-dimensional Ward identity is found to be fulfilled for one-loop vacuum polarization. This implies that gauge invariance may be prior to Lorentz invariance as a guiding principle in higher-dimensional field theory. As a universal application of electrodynamics, an extra-dimensional aspect for Furry's theorem is emphasized.
Hiding Lorentz invariance violation with MOND
Sanders, R. H.
2011-01-01
Horava-Lifshitz gravity is an attempt to construct a renormalizable theory of gravity by breaking the Lorentz invariance of the gravitational action at high energies. The underlying principle is that Lorentz invariance is an approximate symmetry and its violation by gravitational phenomena is
Constraints on Lorentz violation from gravitational Čerenkov radiation
Directory of Open Access Journals (Sweden)
V. Alan Kostelecký
2015-10-01
Full Text Available Limits on gravitational Čerenkov 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. Prospects are discussed for future analyses incorporating effects of Lorentz violation in the matter sector, the role of gravitational Čerenkov radiation by high-energy photons, data from gravitational-wave observatories, the tired-light effect, and electromagnetic Čerenkov radiation by gravitons.
Constraints on Lorentz violation from gravitational Cherenkov radiation
Kostelecky, Alan
2015-01-01
Limits on gravitational Cherenkov 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. Prospects are discussed for future analyses incorporating effects of Lorentz violation in the matter sector, the role of gravitational Cherenkov radiation by high-energy photons, data from gravitational-wave observatories, the tired-light effect, and electromagnetic Cherenkov radiation by gravitons.
Testing Lorentz invariance in orbital electron capture
Vos, K K; Timmermans, R G E
2015-01-01
Searches for Lorentz violation were recently extended to the weak sector, in particular neutron and nuclear $\\beta$ decay [1]. From experiments on forbidden $\\beta$-decay transitions strong limits in the range of $10^{-6}$-$10^{-8}$ were obtained on Lorentz-violating components of the $W$-boson propagator [2]. In order to improve on these limits strong sources have to be considered. In this Brief Report we study isotopes that undergo orbital electron capture and allow experiments at high decay rates and low dose. We derive the expressions for the Lorentz-violating differential decay rate and discuss the options for competitive experiments and their required precision.
Lorentz violation. Motivation and new constraints
Energy Technology Data Exchange (ETDEWEB)
Liberati, S. [Scuola Internazionale Superiore di Studi Avanzati SISSA, Trieste (Italy); Istituto Nazionale di Fisica Nucleare INFN, Sezione di Trieste (Italy); Maccione, L. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2009-09-15
We review the main theoretical motivations and observational constraints on Planck scale sup-pressed violations of Lorentz invariance. After introducing the problems related to the phenomenological study of quantum gravitational effects, we discuss the main theoretical frameworks within which possible departures from Lorentz invariance can be described. In particular, we focus on the framework of Effective Field Theory, describing several possible ways of including Lorentz violation therein and discussing their theoretical viability. We review the main low energy effects that are expected in this framework. We discuss the current observational constraints on such a framework, focusing on those achievable through high-energy astrophysics observations. In this context we present a summary of the most recent and strongest constraints on QED with Lorentz violating non-renormalizable operators. Finally, we discuss the present status of the field and its future perspectives. (orig.)
Generalizing the Lorentz transformations
Chappell, James M; Iannella, Nicolangelo; Hartnett, John G; Iqbal, Azhar; Abbott, Derek
2016-01-01
In this paper we develop a framework allowing a natural extension of the Lorentz transformations. To begin, we show that by expanding conventional four-dimensional spacetime to eight-dimensions that a natural generalization is indeed obtained. We then find with these generalized coordinate transformations acting on Maxwell's equations that the electromagnetic field transformations are nevertheless unchanged. We find further, that if we assume the absence of magnetic monopoles, in accordance with Maxwell's theory, our generalized transformations are then restricted to be the conventional ones. While the conventional Lorentz transformations are indeed recovered from our framework, we nevertheless provide a new perspective into why the Lorentz transformations are constrained to be the conventional ones. Also, this generalized framework may assist in explaining several unresolved questions in electromagnetism as well as to be able to describe quasi magnetic monopoles found in spin-ice systems.
Lorentz violation in Bhabha scattering at finite temperature
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.
Neutrino Oscillations, Lorentz/CPT Violation, and Dark Energy
Ando, Shin'ichiro; Mocioiu, Irina
2009-01-01
If dark energy (DE) couples to neutrinos, then there may be apparent violations of Lorentz/CPT invariance in neutrino oscillations. The DE-induced Lorentz/CPT violation takes a specific form that introduces neutrino oscillations that are energy independent, differ for particles and antiparticles, and can lead to novel effects for neutrinos propagating through matter. We show that ultra-high-energy neutrinos may provide one avenue to seek this type of Lorentz/CPT violation in \
Looking for Lorentz Violation in Short-Range Gravity
Xu, Rui
2016-01-01
General violations of Lorentz symmetry can be described by the Standard-Model Extension (SME) framework. The SME predicts modifications to existing physics and can be tested in high-precision experiments. By looking for small deviations from Newton gravity, short-range gravity experiments are expected to be sensitive to possible gravitational Lorentz-violation signals. With two group's short-range gravity data analyzed recently, no nonminimal Lorentz violation signal is found at the micron distance scale, which gives stringent constraints on nonminimal Lorentz-violation coefficients in the SME.
Gamma-Ray, Cosmic Ray and Neutrino Tests of Lorentz Invariance and Quantum Gravity Models
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.
Lorentz invariance violation and generalized uncertainty principle
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.
Lorentz-Force Hydrophone Characterization
Grasland-Mongrain, Pol; Gilles, Bruno; Poizat, Adrien; Chapelon, Jean-Yves; Lafon, Cyril
2014-01-01
A Lorentz-force hydrophone consists of a thin wire placed inside a magnetic field. When under the influence of an ultrasound pulse, the wire vibrates and an electrical signal is induced by the Lorentz force that is proportional to the pulse amplitude. In this study a compact prototype of such a hydrophone is introduced and characterized, and the hydrodynamic model previously developed is refined. It is shown that the wire tension has a negligible effect on the measurement of pressure. The frequency response of the hydrophone reaches 1 MHz for wires with a diameter ranging between 70 and 400 \\micro m. The hydrophone exhibits a directional response such that the signal amplitude differs by less than 3dB as the angle of the incident ultrasound pulse varies from -20$^o$ and +20$^o$. The linearity of the measured signal is confirmed across the 50 kPa to 10 MPa pressure range, and an excellent resistance to cavitation is observed. This hydrophone is of interest for high pressure ultrasound measurements including Hi...
Cosmic rays and the search for a Lorentz Invariance Violation
Energy Technology Data Exchange (ETDEWEB)
Bietenholz, Wolfgang [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2008-11-15
This is an introductory review about the on-going search for a signal of Lorentz Invariance Violation (LIV) in cosmic rays. We first summarise basic aspects of cosmic rays, focusing on rays of ultra high energy (UHECRs). We discuss the Greisen-Zatsepin-Kuz'min (GZK) energy cutoff for cosmic protons, which is predicted due to photopion production in the Cosmic Microwave Background (CMB). This is a process of modest energy in the proton rest frame. It can be investigated to a high precision in the laboratory, if Lorentz transformations apply even at factors {gamma} {proportional_to} O(10{sup 11}). For heavier nuclei the energy attenuation is even faster due to photo-disintegration, again if this process is Lorentz invariant. Hence the viability of Lorentz symmetry up to tremendous {gamma}-factors - far beyond accelerator tests - is a central issue. Next we comment on conceptual aspects of Lorentz Invariance and the possibility of its spontaneous breaking. This could lead to slightly particle dependent ''Maximal Attainable Velocities''. We discuss their effect in decays, Cerenkov radiation, the GZK cutoff and neutrino oscillation in cosmic rays. We also review the search for LIV in cosmic {gamma}-rays. For multi TeV {gamma}-rays we possibly encounter another puzzle related to the transparency of the CMB, similar to the GZK cutoff, due to electron/positron creation and subsequent inverse Compton scattering. The photons emitted in a Gamma Ray Burst occur at lower energies, but their very long path provides access to information not far from the Planck scale. We discuss conceivable non-linear photon dispersions based on non-commutative geometry or effective approaches. No LIV has been observed so far. However, even extremely tiny LIV effects could change the predictions for cosmic ray physics drastically. An Appendix is devoted to the recent hypothesis by the Pierre Auger Collaboration, which identifies nearby Active Galactic Nuclei - or objects
Lorentz violation and neutrino oscillations
Energy Technology Data Exchange (ETDEWEB)
Mewes, Matthew [Marquette University, P.O. Box 1881, Milwaukee, WI 53201 (United States)
2011-12-15
Lorentz violation naturally leads to neutrino oscillations and provides an alternative mechanism that may explain current data. This contribution to the proceedings of The XXII International Conference on Neutrino Physics and Astrophysics provides a brief review of possible signals of Lorentz violation in neutrino-oscillation experiments.
Bluhm, R
2004-01-01
A status report is given of some recent theoretical and experimental investigations looking for signals of Lorentz violation in QED. Experiments with light, charged particles, and atoms have exceptional sensitivity to small shifts in energy caused by Lorentz violation, including effects that could originate from new physics at the Planck scale.
Restrictive scenarios from Lorentz Invariance Violation to cosmic rays propagation
Martínez-Huerta, H
2016-01-01
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 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.
Realisation of a Lorentz algebra in Lorentz violating theory
Energy Technology Data Exchange (ETDEWEB)
Ganguly, Oindrila [S. N. Bose National Centre for Basic Sciences, Kolkata (India)
2012-11-15
A Lorentz non-invariant higher derivative effective action in flat spacetime, characterised by a constant vector, can be made invariant under infinitesimal Lorentz transformations by restricting the allowed field configurations. These restricted fields are defined as functions of the background vector in such a way that background dependence of the dynamics of the physical system is no longer manifest. We show here that they also provide a field basis for the realisation of a Lorentz algebra and allow the construction of a Poincare invariant symplectic two-form on the covariant phase space of the theory. (orig.)
Amplitude modulated Lorentz force MEMS magnetometer with picotesla sensitivity
Kumar, Varun; Ramezany, Alireza; Mahdavi, Mohammad; Pourkamali, Siavash
2016-10-01
This paper demonstrates ultra-high sensitivities for a Lorentz force resonant MEMS magnetometer enabled by internal-thermal piezoresistive vibration amplification. A detailed model of the magneto-thermo-electro-mechanical internal amplification is described and is in good agreement with the experimental results. Internal amplification factors up to ~1620 times have been demonstrated by artificially boosting the effective quality factor of the resonator from 680 to 1.14 × 106 by tuning the bias current. The increase in the resonator bias current in addition to the improvement in the quality factor of the device led to a sensitivity enhancement by ~2400 times. For a bias current of 7.245 mA, where the effective quality factor of the device and consequently the sensitivity is maximum (2.107 mV nT-1), the noise floor is measured to be as low as 2.8 pT (√Hz)-1. This is by far the most sensitive Lorentz force MEMS magnetometer demonstrated to date.
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.
Astroparticle tests of Lorentz symmetry
Energy Technology Data Exchange (ETDEWEB)
Diaz, Jorge [Karlsruhe Institute of Technology, Karlsruhe (Germany)
2016-07-01
Lorentz symmetry is a cornerstone of modern physics. As the spacetime symmetry of special relativity, Lorentz invariance is a basic component of the standard model of particle physics and general relativity, which to date constitute our most successful descriptions of nature. Deviations from exact symmetry would radically change our view of the universe and current experiments allow us to test the validity of this assumption. In this talk, I describe effects of Lorentz violation in cosmic rays and gamma rays that can be studied in current observatories.
Lorentz Harmonics, Squeeze Harmonics and Their Physical Applications
Directory of Open Access Journals (Sweden)
Marilyn E. Noz
2011-02-01
Full Text Available Among the symmetries in physics, the rotation symmetry is most familiar to us. It is known that the spherical harmonics serve useful purposes when the world is rotated. Squeeze transformations are also becoming more prominent in physics, particularly in optical sciences and in high-energy physics. As can be seen from Dirac’s light-cone coordinate system, Lorentz boosts are squeeze transformations. Thus the squeeze transformation is one of the fundamental transformations in Einstein’s Lorentz-covariant world. It is possible to define a complete set of orthonormal functions defined for one Lorentz frame. It is shown that the same set can be used for other Lorentz frames. Transformation properties are discussed. Physical applications are discussed in both optics and high-energy physics. It is shown that the Lorentz harmonics provide the mathematical basis for squeezed states of light. It is shown also that the same set of harmonics can be used for understanding Lorentz-boosted hadrons in high-energy physics. It is thus possible to transmit physics from one branch of physics to the other branch using the mathematical basis common to them.
Test of Lorentz Violation with Astrophysical Neutrino Flavor
Katori, Teppei; Salvado, Jordi
2016-01-01
The high-energy astrophysical neutrinos recently discovered by IceCube opened a new way to test Lorentz and CPT violation through the astrophysical neutrino mixing properties. The flavor ratio of astrophysical neutrinos is a very powerful tool to investigate tiny effects caused by Lorentz and CPT violation. There are 3 main findings; (1) current limits on Lorentz and CPT violation in neutrino sector are not tight and they allow for any flavor ratios, (2) however, the observable flavor ratio on the Earth is tied with the flavor ratio at production, this means we can test both the presence of new physics and the astrophysical neutrino production mechanism simultaneously, and (3) the astrophysical neutrino flavor ratio is one of the most stringent tests of Lorentz and CPT violation.
Lorentz breaking Effective Field Theory and observational tests
Liberati, Stefano
2012-01-01
Analogue models of gravity have provided an experimentally realizable test field for our ideas on quantum field theory in curved spacetimes but they have also inspired the investigation of possible departures from exact Lorentz invariance at microscopic scales. In this role they have joined, and sometime anticipated, several quantum gravity models characterized by Lorentz breaking phenomenology. A crucial difference between these speculations and other ones associated to quantum gravity scenarios, is the possibility to carry out observational and experimental tests which have nowadays led to a broad range of constraints on departures from Lorentz invariance. We shall review here the effective field theory approach to Lorentz breaking in the matter sector, present the constraints provided by the available observations and finally discuss the implications of the persisting uncertainty on the composition of the ultra high energy cosmic rays for the constraints on the higher order, analogue gravity inspired, Lore...
Tests of Lorentz Symmetry in the Gravitational Sector
Directory of Open Access Journals (Sweden)
Aurélien Hees
2016-12-01
Full Text Available Lorentz symmetry is one of the pillars of both General Relativity and the Standard Model of particle physics. Motivated by ideas about quantum gravity, unification theories and violations of CPT symmetry, a significant effort has been put the last decades into testing Lorentz symmetry. This review focuses on Lorentz symmetry tests performed in the gravitational sector. We briefly review the basics of the pure gravitational sector of the Standard-Model Extension (SME framework, a formalism developed in order to systematically parametrize hypothetical violations of the Lorentz invariance. Furthermore, we discuss the latest constraints obtained within this formalism including analyses of the following measurements: atomic gravimetry, Lunar Laser Ranging, Very Long Baseline Interferometry, planetary ephemerides, Gravity Probe B, binary pulsars, high energy cosmic rays, … In addition, we propose a combined analysis of all these results. We also discuss possible improvements on current analyses and present some sensitivity analyses for future observations.
Tests of Lorentz symmetry in the gravitational sector
Hees, Aurélien; Bourgoin, Adrien; Bars, Hélène Pihan-Le; Guerlin, Christine; Poncin-Lafitte, Christophe Le
2016-01-01
Lorentz symmetry is one of the pillars of both General Relativity and the Standard Model of particle physics. Motivated by ideas about quantum gravity, unification theories and violations of CPT symmetry, a significant effort has been put the last decades into testing Lorentz symmetry. This review focuses on Lorentz symmetry tests performed in the gravitational sector. We briefly review the basics of the pure gravitational sector of the Standard-Model Extension (SME) framework, a formalism developed in order to systematically parametrize hypothetical violations of the Lorentz invariance. Furthermore, we discuss the latest constraints obtained within this formalism including analyses of the following measurements: atomic gravimetry, Lunar Laser Ranging, Very Long Baseline Interferometry, planetary ephemerides, Gravity Probe B, binary pulsars, high energy cosmic rays,... In addition, we propose a combined analysis of all these results. We also discuss possible improvements on current analyses and present some s...
Astroparticle Physics Tests of Lorentz Invariance Violation
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.
Lorentz transformations: Einstein's derivation simplified
Rothenstein, B; Popescu, Stefan; Rothenstein, Bernhard
2007-01-01
We show that the Lorentz transformations for the space-time coordinates of the same event are a direct consequence of the principle of relativity and of Einstein's distant clocks synchronization procedure. In our approach, imposing the linear character of the Lorentz transformations we guess that the transformation equation for the space coordinate has the form x=ax'+cbt'. Imposing the condition that it accounts for the time dilation relativistic effect and taking into account the fact that due to the clock synchronization a la Einstein the space-time coordinates of the same event in the two frames are related by x=ct and x'=ct', we find out expressions for a and b. Dividing the transformation equation for the space coordinate by c we obtain the transformation equation for the time coordinate t=at'+b/cx'. Combining the two transformation equations we obtain directly the inverse Lorentz transformations.
Lorentz-violating inflationary magnetogenesis
Energy Technology Data Exchange (ETDEWEB)
Campanelli, Leonardo [Universita di Bari, Dipartimento di Fisica, Bari (Italy)
2015-06-15
A non-conformally invariant coupling between the inflaton and the photon in the minimal Lorentz-violating standard model extension is analyzed. For specific forms of the Lorentz-violating background tensor, the strong-coupling and back-reaction problems of magnetogenesis in de Sitter inflation with scale ∝ 10{sup 16} GeV are evaded, the electromagnetic-induced primordial spectra of (Gaussian and non-Gaussian) scalar and tensor curvature perturbations are compatible with cosmic microwave background observations, and the inflation-produced magnetic field directly accounts for cosmic magnetic fields. (orig.)
Neutrino mixing and Lorentz invariance
Blasone, M; Pires-Pacheco, P; Blasone, Massimo; Magueijo, Joao; Pires-Pacheco, Paulo
2003-01-01
We use previous work on the Hilbert space for mixed fields to derive deformed dispersion relations for neutrino flavor states. We then discuss how these dispersion relations may be incorporated into frameworks encoding the breakdown of Lorentz invariance. We consider non-linear relativity schemes (of which doubly special relativity is an example), and also frameworks allowing for the existence of a preferred frame. In both cases we derive expressions for the spectrum and end-point of beta decay, which may be used as an experimental probe of the peculiar way in which neutrinos experience Lorentz invariance.
Lorentz violation, gravity, dissipation and holography
National Research Council Canada - National Science Library
Kiritsis, Elias
2013-01-01
We reconsider Lorentz Violation (LV) at the fundamental level. We argue that Lorentz Violation is intimately connected with gravity and that LV couplings in QFT must always be fields in a gravitational sector...
Transport properties of stochastic Lorentz models
Beijeren, H. van
1982-01-01
Diffusion processes are considered for one-dimensional stochastic Lorentz models, consisting of randomly distributed fixed scatterers and one moving light particle. In waiting time Lorentz models the light particle makes instantaneous jumps between scatterers after a stochastically distributed waiti
Strongly enhanced effects of Lorentz symmetry violation in entangled Yb+ ions
Dzuba, V A; Safronova, M S; Porsev, S G; Pruttivarasin, T; Hohensee, M A; Häffner, H
2015-01-01
Lorentz symmetry is one of the cornerstones of modern physics. However, a number of theories aiming at unifying gravity with the other fundamental interactions including string field theory suggest violation of Lorentz symmetry [1-4]. While the energy scale of such strongly Lorentz symmetry-violating physics is much higher than that currently attainable by particle accelerators, Lorentz violation may nevertheless be detectable via precision measurements at low energies [2]. Here, we carry out a systematic theoretical investigation of the sensitivity of a wide range of atomic systems to violation of local Lorentz invariance (LLI). Aim of these studies is to identify which atom shows the biggest promise to detect violation of Lorentz symmetry. We identify the Yb+ ion as an ideal system with high sensitivity as well as excellent experimental controllability. By applying quantum information inspired technology to Yb+, we expect tests of LLI violating physics in the electron-photon sector to reach levels of $10^{-...
Nuclear beta decay with Lorentz violation
Noordmans, J.P.; Wilschut, H. W.; Timmermans, R. G. E.
2013-01-01
We consider the possibility of Lorentz-invariance violation in weak-decay processes. We present a general approach that entails modifying the W-boson propagator by adding a Lorentz-violating tensor to it. We describe the effects of Lorentz violation on nuclear beta decay in this scenario. In
Testing local Lorentz invariance with gravitational waves
Kostelecky, Alan
2016-01-01
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.
Testing local Lorentz invariance with gravitational waves
Energy Technology Data Exchange (ETDEWEB)
Kostelecký, V. Alan, E-mail: kostelec@indiana.edu [Physics Department, Indiana University, Bloomington, IN 47405 (United States); Mewes, Matthew [Physics Department, California Polytechnic State University, San Luis Obispo, CA 93407 (United States)
2016-06-10
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.
Supergravity with broken Lorentz invariance
Directory of Open Access Journals (Sweden)
Marakulin Arthur
2016-01-01
Full Text Available The supersymmetric extension of the Lorentz violating Einstein-aether theory of gravity is considered. The most general Lagrangian of the linearized Einstein-aether supergravity is constructed using the superfield formalism. The constraints imposed by supersymmetry on the parameters of the theory are obtained.
One way to Lorentz's Transformations
Bessonov, E G
2012-01-01
The derivation of Lorentz Transformations (LT) based on the Principle of Relativity and dependence of the rate of clocks tick (time dilation) on their velocity is presented. The analysis of different ways of the LT derivation allows to look at LT and their consequences from different standpoints, to make them more accessible to a wide circle of readers interested in the relativistic physics.
Testing Lorentz invariance emergence in Ising Model using lattice Monte Carlo simulations
Stojku, Stefan
2017-01-01
All measurements performed so far at the observable energy scales show no violation of Lorentz invariance. However, it is yet impossible to check experimentally whether this symmetry holds at high energies such as the Planck scale. Recently, theories of gravitation with Lorentz violation, known as Horava-Lifshitz gravity [1, 2] have gained signiﬁcant attention by treating Lorentz symmetry as an emergent phenomenon. A Lif-shitz type theory assumes an anisotropic scaling between space and time weighted by some critical exponent. In order for these theories to be viable candidates for quantum gravity description of the nature, Lorentz symmetry needs to be recovered at low energies.
Spontaneously broken Lorentz symmetry and gravity
Jacobson, T; Jacobson, Ted; Mattingly, David
2000-01-01
We study a generally covariant model in which local Lorentz invariance is broken "spontaneously" by a dynamical unit timelike vector field $u^a$---the "aether". Such a model makes it possible to study the gravitational and cosmological consequences of preferred frame effects, such as ``variable speed of light" or high frequency dispersion, while preserving a generally covariant metric theory of gravity. In this paper we restrict attention to an action for an effective theory of the aether which involves only the antisymmetrized derivative $\
Testing Lorentz violation using propagating UHECRs
Institute of Scientific and Technical Information of China (English)
Cong-Xin Qiu; Zi-Gao Dai
2009-01-01
Lorentz invariant violation (LIV) test is important for studying modem physics.All the known astrophysical constraints either have a very small examinable parameter space or are only suitable for some special theoretical models. Here, we suggest that it is possible to directly detect the time-delay of ultra-high-energy cosmic-rays (UHECRs). We discuss some difficulties in our method, including the intergalactic magnetic fields. It seems that none of them are crucial, hence this method could give a larger examinable parameter space and a stronger constraint on LIV.
Mixed Lorentz boosted $Z^{0}'s$
Kjaer, N J
2001-01-01
A novel technique is proposed to study systematic errors on jet reconstruction in W physics measurements at LEP2 with high statistical precision. The method is based on the emulation of W pair events using Mixed Lorentz Boosted Z0 events. The scope and merits of the method and its statistical accuracy are discussed in the context of the DELPHI W mass measurement in the fully hadronic channel. The numbers presented are preliminary in the sense that they do not constitute the final DELPHI systematic errors.
Lorentz violation in brane cosmology, accelerated expansion and fundamental constants
Ahmadi, F; Sepangi, H R
2006-01-01
The notion of Lorentz violation in four dimensions is extended to a 5-dimensional brane-world scenario by utilizing a dynamical vector field assumed to point in the bulk direction, with Lorentz invariance holding on the brane. The cosmological consequences of this theory consisting of the time variation in the gravitational coupling $G$ and cosmological term $\\Lambda_4$ are explored. The brane evolution is addressed by studying the generalized Friedmann and Raychaudhuri equations. The behavior of the expansion scale factor is then considered for different possible scenarios where the bulk cosmological constant is zero, positive or negative.
Restrictions from Lorentz invariance violation on cosmic ray propagation
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.
Lorentz Force Electrical Impedance Tomography
Grasland-Mongrain, Pol; Chapelon, Jean-Yves; Lafon, Cyril
2014-01-01
This article describes a method called Lorentz Force Electrical Impedance Tomography. The electrical conductivity of biological tissues can be measured through their sonication in a magnetic field: the vibration of the tissues inside the field induces an electrical current by Lorentz force. This current, detected by electrodes placed around the sample, is proportional to the ultrasonic pressure, to the strength of the magnetic field and to the electrical conductivity gradient along the acoustic axis. By focusing at different places inside the sample, a map of the electrical conductivity gradient can be established. In this study experiments were conducted on a gelatin phantom and on a beef sample, successively placed in a 300 mT magnetic field and sonicated with an ultrasonic transducer focused at 21 cm emitting 500 kHz bursts. Although all interfaces are not visible, in this exploratory study a good correlation is observed between the electrical conductivity image and the ultrasonic image. This method offers...
Testing Lorentz Symmetry with Lunar Laser Ranging
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.
Concurrent tests of Lorentz invariance in $\\beta$-decay experiments
Vos, K K; Timmermans, R G E
2015-01-01
Modern experiments on neutron and allowed nuclear $\\beta$ decay search for new semileptonic interactions, beyond the ``left-handed'' electroweak force. We show that ongoing and planned $\\beta$-decay experiments, with isotopes at rest and in flight, can be exploited as sensitive tests of Lorentz invariance. The variety of correlations that involve the nuclear spin, the direction of the emitted $\\beta$ particle, and the recoil direction of the daughter nucleus allow for relatively simple experiments that give direct bounds on Lorentz violation. The pertinent observables are decay-rate asymmetries and their dependence on sidereal time. We discuss the potential of several asymmetries that together cover a large part of the parameter space for Lorentz violation in the gauge sector. High counting statistics is required.
Lorentz Violation in Deep Inelastic Electron-Proton Scattering
Lunghi, Enrico
2016-01-01
Lorentz violation in the quark sector induces a sidereal time dependence in electron-proton, proton-antiproton and proton-proton cross sections. At high energies nonperturbative effects are buried in universal nucleon parton distribution functions and Lorentz violating effects are calculable in perturbation theory. We focus on deep inelastic electron-proton scattering data collected from ZEUS and H1 at HERA and show that a sideral time analysis of these events is able to set strong constraints on most of the coefficients we consider.
Lorentz-to-Gauss multiplication (LGM) in FT NMR
Energy Technology Data Exchange (ETDEWEB)
Makhiyanov, N. [Production Association ``Nizhnekamskneftekhym``, Nizhnekamsk, Tatarstan (Russian Federation); Kupka, T. [Uniwersytet Slaski, Katowice (Poland)]|[Zaklad Fizyki Ciala Stalego, Polska Akademia Nauk, Zabrze (Poland); Pasterna, G. [Institute of Nuclear Physics, Cracow (Poland); Dziegielewski, J.O. [Uniwersytet Slaski, Katowice (Poland)
1994-12-31
High resolution proton and carbon NMR spectra of macromolecules and biomolecules are often overcrowded and with many partly overlapped signals. Several data processing methods to resolve partly overlapped NMR peaks have been reported. Among the Lorentz-to-Gauss and CDRE (Convulsion Difference Resolution Enhancement) methods are wide used. In this work calculation of the best set of parameters were carried out from a raw spectral data (initial FID and the corresponding untreated spectrum) and a method of prediction of optimal Lorentz-to-Gauss method parameters are suggested. The feasibility of this approach to improve the quality of NMR spectra from various resonating nuclei was shown too. 8 refs, 1 fig.
Background Dependent Lorentz Violation from String Theory
Li, Tianjun
2011-01-01
We revisit Lorentz violations in the Type IIB string theory with D3-branes and D7-branes. We study the relativistic particle velosities in details, and show that there exist both subluminal and superluminal particle propagations. In particular, the additional contributions to the particle velosity \\delta v\\equiv (v-c)/c from string theory is proportional to both the particle energy and the D3-brane number density, and is inversely proportional to the string scale. Thus, we can realize the background dependent Lorentz violation naturally by varying the D3-brane number density in space time. To explain the superluminal neutrino propagations in the OPERA and MINOS experiments, we obtain the string scale should be around 10^5 GeV. With very tiny D3-brane number density at the interstellar scale, we can also explain the time delays for the high energy photons compared to the low energy photons in the MAGIC, HESS, and FERMI experiments simultaneously. Interestingly, we can automatically satisfy all the stringent co...
Kink shape solutions of the Maxwell-Lorentz system
DEFF Research Database (Denmark)
Sørensen, Mads Peter; Webb, G.M.; Brio, M.
2005-01-01
In the limit of high amplitude oscillating electromagnetic fields, a sequence of kink antikink shaped optical waves has been found in the Maxwell's equations coupled to a single Lorentz oscillator and with Kerr nonlinearity. The individual kinks and antikinks result from a traveling wave assumpti...
Constraints on nonmetricity from bounds on Lorentz violation
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 .
Propagation of a radial phased-locked Lorentz beam array in turbulent atmosphere.
Zhou, Guoquan
2011-11-21
A radial phased-locked (PL) Lorentz beam array provides an appropriate theoretical model to describe a coherent diode laser array, which is an efficient radiation source for high-power beaming use. The propagation of a radial PL Lorentz beam array in turbulent atmosphere is investigated. Based on the extended Huygens-Fresnel integral and some mathematical techniques, analytical formulae for the average intensity and the effective beam size of a radial PL Lorentz beam array are derived in turbulent atmosphere. The average intensity distribution and the spreading properties of a radial PL Lorentz beam array in turbulent atmosphere are numerically calculated. The influences of the beam parameters and the structure constant of the atmospheric turbulence on the propagation of a radial PL Lorentz beam array in turbulent atmosphere are discussed in detail.
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.
Dynamical properties of the Lorentz gas
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.
Lorentz Invariance Violation and Generalized Uncertainty Principle
Tawfik, A; Ali, A Farag
2016-01-01
Recent approaches for quantum gravity are conjectured to give predictions for a minimum measurable length, a maximum observable momentum and an essential generalization for the Heisenberg uncertainty principle (GUP). The latter is based on a momentum-dependent modification in the standard dispersion relation and leads to Lorentz invariance violation (LIV). The main features of the controversial OPERA measurements on the faster-than-light muon neutrino anomaly are used to calculate the time of flight delays $\\Delta t$ and the relative change $\\Delta v$ in the speed of neutrino in dependence on the redshift $z$. The results are compared with the OPERA measurements. We find that the measurements are too large to be interpreted as LIV. Depending on the rest mass, the propagation of high-energy muon neutrino can be superluminal. The comparison with the ultra high energy cosmic rays seems to reveals an essential ingredient of the approach combining string theory, loop quantum gravity, black hole physics and doubly ...
Possibilities for Lorentz violation in nonleptonic decays
Keri Vos, K.; Wilschut, H.W.; Timmermans, R.G.E.
2015-01-01
The weak interaction offers an interesting portal to search for Lorentz symmetry breaking. We explore the possibilities to study Lorentz violation in nonleptonic decays, focusing on the recent measurement of the KLOE collaboration of the directional dependence of the lifetime of the neutral kaon
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).
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 violation and deep inelastic scattering
Directory of Open Access Journals (Sweden)
V. Alan Kostelecký
2017-06-01
Full Text Available 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.
Lorentz violation and deep inelastic scattering
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.
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
Kostelecky, Alan; Vieira, A R
2016-01-01
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.
Parton model in Lorentz invariant noncommutative space
Haghighat, M.; Ettefaghi, M. M.
2004-08-01
We consider the Lorentz invariant noncommutative QED and complete the Feynman rules for the theory up to the order θ2. In the Lorentz invariant version of the noncommutative QED the particles with fractional charges can be also considered. We show that in the parton model, even at the lowest order, the Bjorken scaling violates as ˜θ2Q4.
Testing Lorentz invariance in β decay
Sytema, Auke
2016-01-01
In this thesis we investigate violation of Lorentz invariance in the weak interaction, specifically in β decay. For this purpose an experiment is performed with nuclear-spin-polarized 20Na that decays by emitting a β particle. Lorentz invariance is the property that the laws of nature do not depend
Question of Lorentz violation in muon decay
Noordmans, J. P.; Onderwater, C. J. G.; Wilschut, H. W.; Timmermans, R. G. E.
2016-01-01
Possibilities to test the Lorentz invariance of the weak interaction in muon decay are considered. We derive the direction-dependent muon-decay rate with a general Lorentz-violating addition to the W-boson propagator. We discuss measurements of the directional and boost dependence of the Michel para
Gluonic Lorentz violation and chiral perturbation theory
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.
Lorentz violation and perpetual motion
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.
Lorentz violation and perpetual motion
Eling, C; Jacobson, T; Wall, A C; Eling, Christopher; Foster, Brendan Z.; Jacobson, Ted; Wall, Aron C.
2007-01-01
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 {\\it perpetuum mobile}, but argue that these can be neglected if the black hole mass is sufficiently large.
Lorentz Invariance at Finite Temperature and Its Effect on Production Rate and Equation of State
Institute of Scientific and Technical Information of China (English)
HE Lian-Yi; ZHUANG Peng-Fei
2004-01-01
The effect of Lorentz invariance breaking on the production rate and the equation of state at finite temperature is investigated in the frame of φ3 theory. The invariance breaking significantly changes the off-shell degree at high temperatures.
Alternative theories of gravity and Lorentz violation
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.
Photon gravitational defection in Lorentz violating scenarios
Accioly, Antonio; Helayël-Neto, José
2016-01-01
The effect of Lorentz symmetry violation in the phenomenon of photon gravitational bending, is investigated. Using a semiclassical approach, where the photon is described by the Carrol-Field-Jackiw (CFJ) electrodynamics which is responsible for implementing the Lorentz symmetry violation, the gravitational deflection angle related to the CFJ photon is computed. As expected, this bending angle experiences a deviation from the usual Einstein result and the latter is recovered in the appropriate limit. A comparison between the theoretical prediction and the experimental results allows to conclude that no trace of Lorentz symmetry breaking is found provided the components of the background vector field are $\\lesssim 10^{-8}$ eV.
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.
Classical Gravitational Interactions and Gravitational Lorentz Force
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
In quantum gauge theory of gravity, the gravitational field is represented by gravitational gauge field.The field strength of gravitational gauge field has both gravitoelectric component and gravitomagnetic component. In classical level, gauge theory of gravity gives classical Newtonian gravitational interactions in a relativistic form. Besides,it gives gravitational Lorentz force, which is the gravitational force on a moving object in gravitomagnetic field The direction of gravitational Lorentz force is not the same as that of classical gravitational Newtonian force. Effects of gravitational Lorentz force should be detectable, and these effects can be used to discriminate gravitomagnetic field from ordinary electromagnetic magnetic field.
Lorentz gauge quantization in synchronous coordinates
Garner, Christopher
2016-01-01
It has been shown that the Gupta-Bleuler method of quantization can be used to impose the Lorentz gauge condition in static space-times but not in cosmological space-times. This implies that the Gupta-Bleuler approach fails in general in non-static space-times. More recently, however, the Dirac method of quantizing constrained dynamical systems has been successfully employed to impose the Lorentz gauge in conformally flat space-times. In this paper we generalize this result by using Dirac's method to impose the Lorentz gauge in a general space-time region where the metric is expressed in synchronous coordinates.
What Do We Know About Lorentz Invariance?
Tasson, Jay D
2014-01-01
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.
Cosmological Background torsion limits from Lorentz violation
Garcia de Andrade, L C
2001-01-01
Cosmological limits on Lorentz invariance breaking in Chern-Simons $(3+1)-dimensional$ electrodynamics are used to place limits on torsion. Birefrigence phenomena is discussed by using extending the propagation equation to Riemann-Cartan spacetimes instead of treating it in purely Riemannian spaces. The parameter of Lorentz violation is shown to be proportional to the axial torsion vector which allows us to place a limit on cosmological background torsion from the Lorentz violation constraint which is given by $ 10^{-33} eV <|S^{\\mu}| < 10^{-32} eV$ where $|S^{\\mu}|$ is the axial torsion vector.
Rubtsov, Grigory; Sibiryakov, Sergey
2016-01-01
We discuss the effect of hypothetical violation of Lorentz invariance at high energies 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.
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.
Constrained gauge fields from spontaneous Lorentz violation
DEFF Research Database (Denmark)
Chkareuli, J. L.; Froggatt, C. D.; Jejelava, J. G.
2008-01-01
Spontaneous Lorentz violation realized through a nonlinear vector field constraint of the type AµAµ=M2 (M is the proposed scale for Lorentz violation) is shown to generate massless vector Goldstone bosons, gauging the starting global internal symmetries in arbitrary relativistically invariant...... theories. The gauge invariance appears in essence as a necessary condition for these bosons not to be superfluously restricted in degrees of freedom, apart from the constraint due to which the true vacuum in a theory is chosen by the Lorentz violation. In the Abelian symmetry case the only possible theory...... proves to be QED with a massless vector Goldstone boson naturally associated with the photon, while the non-Abelian symmetry case results in a conventional Yang-Mills theory. These theories, both Abelian and non-Abelian, look essentially nonlinear and contain particular Lorentz (and CPT) violating...
Grasland-Mongrain, Pol
2014-01-01
The ability of the Lorentz force to link a mechanical displacement to an electrical current presents a strong interest for medical acoustics, and three applications were studied in this thesis. In the first part of this work, a hydrophone was developed for mapping the particle velocity of an acoustic field. This hydrophone was constructed using a thin copper wire and an external magnetic field. A model was elaborated to determine the relationship between the acoustic pressure and the measured electrical current, which is induced by Lorentz force when the wire vibrates in the acoustic field of an ultrasound transducer. The built prototype was characterized and its spatial resolution, frequency response, sensitivity, robustness and directivity response were investigated. An imaging method called Lorentz Force Electrical Impedance Tomography was also studied. In this method, a biological tissue is vibrated by ultrasound in a magnetic field, which induces an electrical current by Lorentz force. The electrical imp...
The Scientific Correspondence of H A Lorentz
Kox, AJ
2008-01-01
Presents a selection of more than 400 letters from and to the Dutch physicist and Nobel Prize winner Hendrik Antoon Lorentz (1853-1928), covering the period from 1883 until a few months before his death.
Recent Progress in Lorentz and CPT Violation
Kostelecky, Alan
2016-01-01
This contribution to the CPT'16 meeting briefly highlights some of the recent progress in the phenomenology of Lorentz and CPT violation, with emphasis on research performed at the Indiana University Center for Spacetime Symmetries.
Antimatter-Gravity Couplings, and Lorentz Symmetry
Tasson, Jay D
2015-01-01
Implications of possible CPT and Lorentz violation for antimatter-gravity experiments as well as other antimatter tests are considered in the context of the general field-theory-based framework of the Standard-Model Extension (SME).
On Lorentz invariants in relativistic magnetic reconnection
Yang, Shu-Di; Wang, Xiao-Gang
2016-08-01
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.
Probes of Lorentz Violation in Neutrino Propagation
Ellis, Jonathan Richard; Meregaglia, Anselmo; Rubbia, André; Sakharov, Alexander S
2008-01-01
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_\
Gauge anomalies in Lorentz-violating QED
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.
Gauge anomalies in Lorentz-violating QED
Santos, Tiago R S
2016-01-01
In this work we study the issue of gauge anomalies in Lorentz-violating QED. To do so, we opt to use the BRST formalism within of the algebraic renormalization approach, reducing our study to a cohomology problem. Since that this approach is independent of the renormalization scheme, the results here obtained are expected to be general. We find that the Lorentz-violating QED is free of gauge anomalies to all orders in perturbation theory.
Black Hole Thermodynamics and Lorentz Symmetry
Jacobson, Ted
2008-01-01
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 the arguments leading to that conclusion. We suggest the implication that Lorentz symmetry should be viewed as an emergent property of the macroscopic world, required by the second law of black hole thermodynamics.
Macroscopic Objects, Intrinsic Spin, and Lorentz Violation
Atkinson, David W; Tasson, Jay D
2013-01-01
The framework of the Standard-Model Extension (SME) provides a relativistic quantum field theory for the study of Lorentz violation. The classical, nonrelativistic equations of motion can be extracted as a limit that is useful in various scenarios. In this work, we consider the effects of certain SME coefficients for Lorentz violation on the motion of macroscopic objects having net intrinsic spin in the classical, nonrelativistic limit.
Lorentz violation and Condensed Matter Physics
Ajaib, Muhammad Adeel
2014-01-01
We present heuristic arguments that hint to a possible connection of Lorentz violation with observed phenomenon in condensed matter physics. Various references from condensed matter literature are cited where operators in the Standard Model Extension (SME) appear to be enhanced. Based on this we propose that, in the non-relativistic limit, Lorentz violation in the context of the SME exhibits itself in various condensed matter systems.
Hadronic Lorentz violation in chiral perturbation theory
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.
Test of Lorentz symmetry with trapped ions
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 violations in multifractal spacetimes
Calcagni, Gianluca
2016-01-01
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 manifest 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 $E_*>10^{14}\\,\\text{GeV}$ (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...
Lorentz violations in multifractal spacetimes
Energy Technology Data Exchange (ETDEWEB)
Calcagni, Gianluca [Instituto de Estructura de la Materia, CSIC, Madrid (Spain)
2017-05-15
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{sub *} > 10{sup 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{sub *} > 10{sup 17} GeV or greater. (orig.)
Lorentz violations in multifractal spacetimes
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.
Fine-tuning problems in quantum field theory and Lorentz invariance
Cortes, J L
2016-01-01
A model with a scalar and a fermion field is used to show how a Lorentz invariance violating high momentum scale, which eliminates all the divergences of the quantum field theory, 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 is determined at one loop.
Temperature of electro dynamic tether for space debris removal and its effect on Lorentz force
2014-01-01
Electrodynamics tether (EDT) systems is expected as an effective system for deorbiting space debris. EDT systems is a high efficiency propulsion system using the Lorentz force generated by the interference with the earth's magnetic field and the current through the tether. The conductivity of the tether varies with temperacture of tether in orbit, and it affects the Lorentz force that EDT systems can generate. Tether temperature in orbit depends on the thermal optical property. However, the s...
Testing Lorentz Invariance Using an Odd-Parity Asymmetric Optical Resonator
Baynes, Fred; Tobar, Michael
2011-01-01
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 $\\sim10^{4}$ 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 non-rotating experiment our result limits the isotropic Lorentz violating parameter $\\tilde{\\kappa}_{tr}$ to 3.4 $\\pm$ 6.2 x $10^{-9}$, 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.
Energy Technology Data Exchange (ETDEWEB)
Borges, L.H.C.; Ferrari, A.F. [Universidade Federal do ABC, Centro de Ciencias Naturais e Humanas, Santo Andre, SP (Brazil); Barone, F.A. [Universidade Federal de Itajuba, IFQ, Itajuba, MG (Brazil)
2016-11-15
This paper is dedicated to the study of interactions between external sources for the electromagnetic field in the presence of Lorentz symmetry breaking. We focus on a higher derivative, Lorentz violating interaction that arises from a specific model that was argued to lead to interesting effects in the low energy phenomenology of light pseudoscalars interacting with photons. The kind of higher derivative Lorentz violating interaction we discuss are called nonminimal. They are usually expected to be relevant only at very high energies, but we argue they might also induce relevant effects in low energy phenomena. Indeed, we show that the Lorentz violating background considered by us leads to several phenomena that have no counterpart in Maxwell theory, such as nontrivial torques on isolated electric dipoles, as well as nontrivial forces and torques between line currents and point like charges, as well as among Dirac strings and other electromagnetic sources. (orig.)
Lorentz noninvariant oscillations of massless neutrinos are excluded
Barger, Vernon; Marfatia, Danny; Whisnant, Kerry
2011-01-01
The bicycle model of Lorentz noninvariant neutrino oscillations without neutrino masses naturally predicts maximal mixing and a 1/E dependence of the oscillation argument for muon-neutrino to tau-neutrino oscillations of atmospheric and long-baseline neutrinos, but cannot also simultaneously fit the data for solar neutrinos and KamLAND. We search for other possible structures of the effective Hamiltonian for Lorentz noninvariant oscillations of massless neutrinos that naturally have a 1/E dependence at high neutrino energy. Due to the lack of any evidence for direction dependence, we consider only direction-independent oscillations. Although we find a number of models with a 1/E dependence for atmospheric and long-baseline neutrinos, none can also simultaneously fit solar and KamLAND data.
Sfermions and gauginos in a Lorentz-violating theory
Allen, R E; Allen, Roland E.; Yokoo, Seiichirou
2005-01-01
In Lorentz-violating supergravity, sfermions have spin 1/2 and other unusual properties. If the dark matter consists of such particles, there is a natural explanation for the apparent absence of cusps and other small scale structure: The Lorentz-violating dark matter is cold because of the large particle mass, but still moves at nearly the speed of light. Although the R-parity of a sfermion, gaugino, or gravitino is +1 in the present theory, these particles have an "S-parity'' which implies that the LSP is stable and that they are produced in pairs. On the other hand, they can be clearly distinguished from the superpartners of standard supersymmetry by their highly unconventional properties.
Test of Lorentz invariance in β decay of polarized 20Na
Sytema, A.; van den Berg, J. E.; Böll, O.; Chernowitz, D.; Dijck, E. A.; Grasdijk, J. O.; Hoekstra, S.; Jungmann, K.; Mathavan, S. C.; Meinema, C.; Mohanty, A.; Müller, S. E.; Noordmans, J. P.; Nuñez Portela, M.; Onderwater, C. J. G.; Pijpker, C.; Timmermans, R. G. E.; Vos, K. K.; Willmann, L.; Wilschut, H. W.
2016-08-01
Background: Lorentz invariance is key in our understanding of nature, yet relatively few experiments have tested Lorentz invariance in weak interactions. Purpose: Our goal is to obtain limits on Lorentz-invariance violation in weak interactions, in particular rotational invariance in β decay. Method: We search for a dependence of the lifetime of 20Na nuclei on the nuclear spin direction. Such directional dependence would be evidence for Lorentz-invariance violation in weak interactions. A difference in lifetime between nuclei that are polarized in the east and west direction is searched for. This difference is maximally sensitive to the rotation of the Earth, while the sidereal dependence is free from most systematic errors. Results: The experiment sets a limit of 2 ×10-4 at 90% C.L. on the amplitude of the sidereal variation of the relative lifetime differences, an improvement by a factor 15 compared to an earlier result. Conclusions: No significant violation of Lorentz invariance is found. The result sets limits on parameters of theories describing Lorentz-invariance violation.
Lorentz symmetry and very long baseline interferometry
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.
Lorentz symmetry and Very Long Baseline Interferometry
Poncin-Lafitte, C Le; lambert, S
2016-01-01
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, post-fit analysis of Gravity Probe B and binary pulsars lead to an upper limit at the $10^{-4}$ level on the time-time coefficient $\\bar s^{TT}$ 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 we implement it into a real data analysis code of geodetic VLBI observations. Analyzing all available observations recorded since 1979, we compare estimates of $\\bar s^{TT}$ and errors obtained with various analysis schemes, including global estimations over several time spans and with various Sun elongation cut-off angles, and with analysis of radio source coordinate time series. We obtain a constraint on $\\bar s^{TT}=(-5\\pm 8)\\times 10^{-5}$, directly fitted to the observations and improving by a factor 5 pr...
Lorentz covariance of loop quantum gravity
Rovelli, Carlo
2010-01-01
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 preciseley in K on the boundary. This c...
Lorentz Force Based Satellite Attitude Control
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.
Probe of Lorentz Invariance Violation effects and determination of the distance of PG 1553+113
Sanchez, D A; Couturier, C; Jacholkowska, A
2015-01-01
The high frequency peaked BL Lac object PG 1553+113 underwent a flaring event in 2012. The High Energy Stereoscopic System (H.E.S.S.) observed this source for two consecutive nights at very high energies (VHE, $E>$100~GeV). The data show an increase of a factor of three of the flux with respect to archival measurements with the same instrument and hints of intra-night variability. The data set has been used to put constraints on possible Lorentz invariance violation (LIV), manifesting itself as an energy dependence of the velocity of light in vacuum, and to set limits on the energy scale at which Quantum Gravity effects causing LIV may arise. With a new method to combine H.E.S.S. and Fermi large area telescope data, the previously poorly known redshift of PG 1555+113 has been determined to be close to the value derived from optical measurements.
Baryogenesis in Lorentz-violating gravity theories
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.
Looking for Lorentz violation with gravitational waves
Schreck, M
2016-01-01
The current letter has been inspired by the recent direct detection of gravitational waves reported by Advanced LIGO. In this context, a particular Lorentz-violating framework for classical, massive particles is on the focus. The latter is characterized by a preferred direction in spacetime comprised of CPT-odd components with mass dimension 1. Curvature effects in spacetime, which are caused by a propagating gravitational wave, are assumed to deform the otherwise constant background field. In accordance with spontaneous Lorentz violation, a particular choice for the vector field is taken, which was proposed elsewhere. The geodesic equations for a particle that is subject to this type of Lorentz violation are obtained. Subsequently, their numerical solutions are computed and discussed. The particular model considered leads to changes in the particle trajectory, which interferometric gravitational-wave experiments could be sensitive for. Since such effects have not been observed in the gravitational-wave event...
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.
Velocity in Lorentz-Violating Fermion Theories
Altschul, B D; Colladay, Don
2004-01-01
We consider the role of the velocity in Lorentz-violating fermionic quantum theory, especially emphasizing the nonrelativistic regime. Information about the velocity will be important for the kinematical analysis of scattering and other problems. Working within the minimal standard model extension, we derive new expressions for the velocity. We find that generic momentum and spin eigenstates may not have well-defined velocities. We also demonstrate how several different techniques may be used to shed light on different aspects of the problem. A relativistic operator analysis allows us to study the behavior of the Lorentz-violating Zitterbewegung. Alternatively, by studying the time evolution of Gaussian wave packets, we find that there are Lorentz-violating modifications to the wave packet spreading and the spin structure of the wave function.
Passive Lorentz transformations with spacetime algebra
Paiva, C R
2005-01-01
In special relativity spacetime algebra developed by David Hestenes, STA, provides a powerful and insightful approach to an invariant formulation of physics, the spacetime physics, through an elegant and concise manipulation of active Lorentz transformations. Therefore, it should come as an oddity, to say the least, to relate STA with passive Lorentz transformations. Nevertheless, length contraction, time dilation and all that are the bread and butter of most introductory courses on relativistic physics. To overcome the coordinate virus, it is necessary to be able to translate and dissolve passive Lorentz transformations in the fluidity and flexibility of STA, thereby bridging the gap between relativistic physics and proper spacetime physics. That is the aim of this paper.
Testing Lorentz invariance in weak decays
Energy Technology Data Exchange (ETDEWEB)
Sytema, Auke; Dijck, Elwin; Hoekstra, Steven; Jungmann, Klaus; Mueller, Stefan; Noordmans, Jacob; Onderwater, Gerco; Pijpker, Coen; Timmermans, Rob; Vos, Keri; Willmann, Lorenz; Wilschut, Hans [Van Swinderen Institute, University of Groningen (Netherlands)
2015-07-01
Lorentz invariance is the invariance of physical laws under orientations and boosts. It is a key assumption in Special Relativity and the Standard Model of Particle Physics. Several theories unifying General Relativity and Quantum Mechanics allow breaking of Lorentz invariance. At the Van Swinderen Institute in Groningen a theoretical and experimental research program was started to study Lorentz invariance violation (LIV) in weak interactions. The theoretical work allowed a systematic approach to LIV in weak decays. Limits could be set on parameters that quantify LIV. A novel beta decay experiment was designed which tests rotational invariance with respect to the orientation of nuclear spin. In particular, using the isotope {sup 20}Na, the decay rate dependence on the nuclear polarization direction was measured. Searching for sidereal variations, systematic errors can be suppressed. The result of the experiment is presented.
Test of Lorentz Invariance with Atmospheric Neutrinos
:,; Haga, Y; Hayato, Y; Ikeda, M; Iyogi, K; Kameda, J; Kishimoto, Y; Miura, M; Moriyama, S; Nakahata, M; Nakano, Y; Nakayama, S; Sekiya, H; Shiozawa, M; Suzuki, Y; Takeda, A; Tanaka, H; Tomura, T; Ueno, K; Wendell, R A; Yokozawa, T; Irvine, T; Kajita, T; Kametani, I; Kaneyuki, K; Lee, K P; McLachlan, T; Nishimura, Y; Richard, E; Okumura, K; Labarga, L; Fernandez, P; Gustafson, J; Kearns, E; Raaf, J L; Berkman, S; Tanaka, H A; Tobayama, S; Stone, J L; Sulak, L R; Goldhaber, M; Carminati, G; Kropp, W R; Mine, S; Weatherly, P; Renshaw, A; Smy, M B; Sobel, H W; Takhistov, V; Ganezer, K S; Hartfiel, B L; Hill, J; Keig, W E; Hong, N; Kim, J Y; Lim, I T; Akiri, T; Himmel, A; Scholberg, K; Walter, C W; Wongjirad, T; Ishizuka, T; Tasaka, S; Jang, J S; Learned, J G; Matsuno, S; Smith, S N; Hasegawa, T; Ishida, T; Ishii, T; Kobayashi, T; Nakadaira, T; Nakamura, K; Oyama, Y; Sakashita, K; Sekiguchi, T; Tsukamoto, T; Suzuki, A T; Takeuchi, Y; Bronner, C; Hirota, S; Huang, K; Ieki, K; Kikawa, T; Minamino, A; Murakami, A; Nakaya, T; Suzuki, K; Takahashi, S; Tateishi, K; Fukuda, Y; Choi, K; Itow, Y; Mitsuka, G; Mijakowski, P; Hignight, J; Imber, J; Jung, C K; Yanagisawa, C; Ishino, H; Kibayashi, A; Koshio, Y; Mori, T; Sakuda, M; Yamaguchi, R; Yano, T; Kuno, Y; Tacik, R; Kim, S B; Okazawa, H; Choi, Y; Nishijima, K; Koshiba, M; Suda, Y; Totsuka, Y; Yokoyama, M; Martens, K; Marti, Ll; Vagins, M R; Martin, J F; de Perio, P; Konaka, A; Wilking, M J; Chen, S; Zhang, Y; Connolly, K; Wilkes, R J
2014-01-01
A search for neutrino oscillations induced by Lorentz violation has been performed using 4,438 live-days of Super-Kamiokande atmospheric neutrino data. The Lorentz violation is included in addition to standard three-flavor oscillations using the non-perturbative Standard Model Extension (SME), allowing the use of the full range of neutrino path lengths, ranging from 15 to 12,800 km, and energies ranging from 100 MeV to more than 100 TeV in the search. No evidence of Lorentz violation was observed, so limits are set on the renormalizable isotropic SME coefficients in the $e\\mu$, $\\mu\\tau$, and $e\\tau$ sectors, improving the existing limits by up to seven orders of magnitude and setting limits for the first time in the neutrino $\\mu\\tau$ sector of the SME.
Comments on Holography with Broken Lorentz Invariance
Gordeli, Ivan
2009-01-01
Recently a family of solutions of the Einstein equations in backgrounds with broken Lorentz invariance was found ArXiv:0712.1136. We show that the gravitational solution recently obtained by Kachru, Liu and Mulligan in ArXiv:0808.1725 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. At the end we speculate on relations between the RG flow of a boundary theory and asymptotic behavior of gravitational solutions in the bulk.
Lorentz violation in simple QED processes
de Brito, G P; Kroff, D; Malta, P C; Marques, C
2016-01-01
We determine the effect of a CPT-even and Lorentz violating non-minimal coupling on the differential cross sections for some of the most important tree-level processes in QED, namely, Compton and Bhabha scatterings, as well as electron-positron annihilation. Experimental limits constraining the allowed deviation of the differential cross sections relative to pure QED allow us to place upper bounds on the Lorentz violating parameters. A constraint based on the decay rate of para-positronium is also obtained.
Deduction of Lorentz Transformations from Classical Thermodynamics
Directory of Open Access Journals (Sweden)
Angela M. Ares de Parga
2015-01-01
Full Text Available The Lorentz transformations are obtained by assuming that the laws of classical thermodynamics are invariant under changes of inertial reference frames. As Maxwell equations are used in order to deduce a wave equation that shows the constancy of the speed of light, by means of the laws of classical thermodynamics, the invariance of the Carnot cycle is deduced under reference frame changes. Starting with this result and the blackbody particle number density in a rest frame, the Lorentz transformations are obtained. A discussion about the universality of classical thermodynamics is given.
Einstein-Yang-Mills-Lorentz Black Holes
Cembranos, Jose A R
2015-01-01
Different black hole solutions of the coupled Einstein-Yang-Mills equations are well known from long time. They have attracted much attention from mathematicians and physicists from their discovery. In this work, we analyze black holes associated with the gauge Lorentz group. In particular, we study solutions which identify the gauge connection with the spin connection. This ansatz allows to find exact solutions to the complete system of equations. By using this procedure, we show the equivalence between the Yang-Mills-Lorentz model in curved space-time and a particular set of extended gravitational theories.
Black Hole Thermodynamics and Lorentz Symmetry
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.
Testing Lorentz Symmetry using Chiral Perturbation Theory
Noordmans, J P
2016-01-01
We consider the low-energy effects of a selected set of Lorentz- and CPT-violating quark and gluon operators by deriving the corresponding chiral effective lagrangian. Using this effective lagrangian, low-energy hadronic observables can be calculated. We apply this to magnetometer experiments and derive the best bounds on some of the Lorentz-violating coefficients. We point out that progress can be made by studying the nucleon-nucleon potential, and by considering storage-ring experiments for deuterons and other light nuclei.
Particle-Dependent Deformations of Lorentz Symmetry
Directory of Open Access Journals (Sweden)
Giovanni Amelino-Camelia
2012-07-01
Full Text Available I report results suggesting that it is possible to introduce laws of relativistic kinematics endowing different types of particles with suitably different deformed-Lorentz-symmetry properties. I also consider some possible applications of these results, among which I highlight those relevant for addressing a long-standing challenge in the description of composite particles, such as atoms, within quantum-gravity-inspired scenarios with Planck-scale deformations of Lorentz symmetry. Some of the new elements here introduced in the formulation of relativistic kinematics appear to also provide the starting point for the development of a correspondingly novel mathematical formulation of spacetime-symmetry algebras.
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.
The Lorentz Theory of Electrons and Einstein's Theory of Relativity
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…
Isogeometric Simulation of Lorentz Detuning in Superconducting Accelerator Cavities
Corno, Jacopo; De Gersem, Herbert; Schöps, Sebastian
2016-01-01
Cavities in linear accelerators suffer from eigenfrequency shifts due to mechanical deformation caused by the electromagnetic radiation pressure, a phenomenon known as Lorentz detuning. Estimating the frequency shift up to the needed accuracy by means of standard Finite Element Methods, is a complex task due to the non exact representation of the geometry and due to the necessity for mesh refinement when using low order basis functions. In this paper, we use Isogeometric Analysis for discretising both mechanical deformations and electromagnetic fields in a coupled multiphysics simulation approach. The combined high-order approximation of both leads to high accuracies at a substantially lower computational cost.
On the Origin of Gravitational Lorentz Covariance
Khoury, Justin; Tolley, Andrew J
2013-01-01
We provide evidence that general relativity is the unique spatially covariant effective field theory of the transverse, traceless graviton degrees of freedom. The Lorentz covariance of general relativity, having not been assumed in our analysis, is thus plausibly interpreted as an accidental or emergent symmetry of the gravitational sector.
Testing Lorentz and CPT invariance with neutrinos
Diaz, Jorge S
2016-01-01
Neutrino experiments can be considered sensitive tools to test Lorentz and CPT invariance. Taking advantage of the great variety of neutrino experiments, including neutrino oscillations, weak decays, and astrophysical neutrinos, the generic experimental signatures of the breakdown of these fundamental symmetries in the neutrino sector are presented.
Emergent Lorentz invariance in fermion sector
Directory of Open Access Journals (Sweden)
Kharuk Ivan
2016-01-01
Full Text Available By using holographic description of strongly interacting field theories we show that under common assumptions Lorentz invariance emerges as an effective low–energy symmetry of the theory, despite fundamental theory at hight energies being Lorentz–violating. We consider fermions sector and show that the notion of chirality also automatically arises in the infrared.
Extra dimensions and violations of Lorentz symmetry
Overduin, James M
2016-01-01
We use experimental limits on Lorentz violation to obtain new constraints on Kaluza-Klein-type theories in which the extra dimensions may be large but do not necessarily have units of length. The associated variation in fundamental quantities such as rest mass must occur slowly, on cosmological scales.
Testing Lorentz invariance in orbital electron capture
Vos, K. K.; Wilschut, H. W.; Timmermans, R. G. E.
2015-01-01
Searches for Lorentz violation were recently extended to the weak sector, in particular neutron and nuclear beta decay [Noordmans, Wilschut, and Timmermans, Phys. Rev. C 87, 055502 (2013)]. From experiments on forbidden beta-decay transitions, strong limits in the range of 10(-6) to 10(-8) were obta
Lorentz Spengler's descriptions of chitons (Mollusca: Polyplacophora)
Kaas, P.; Knudsen, J.
1992-01-01
The present paper deals with an important Danish paper on the Polyplacophora, published in 1797 by Lorentz Spengler: Udförlig Beskrivelse over det mangeskallede Konkylie-Slaegt, af Linnaeus kaldet Chiton; med endeel nye Arter og Varieteter. -Skrivter af Naturhistorie-Selskabet, 4e Bind, Ie Hefte, VI
Lorentz Violating Julia-Toulouse Mechanism
Gaete, P; Gaete, Patricio; Wotzasek, Clovis
2007-01-01
We propose a new Lorentz invariant violating extension for the pure photonic sector of the Standard Model due to the condensation of topological defects in the context of the Julia-Toulouse mechanism. Possible physical consequences leading to direct measurable effects over the confining properties of the elementary particles are explored.
Interpolation theorems on weighted Lorentz martingale spaces
Institute of Scientific and Technical Information of China (English)
2007-01-01
In this paper several interpolation theorems on martingale Lorentz spaces are given.The proofs are based on the atomic decompositions of martingale Hardy spaces over weighted measure spaces.Applying the interpolation theorems,we obtain some inequalities on martingale transform operator.
Constraining Anisotropic Lorentz Violation via the Spectral-lag Transition of GRB 160625B
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.
High Power Factor Power Design
Directory of Open Access Journals (Sweden)
Zhang Jing-yi
2013-07-01
Full Text Available The PFC circuit takes UCC28019 made by TI Company as the core of system control, realize the power factor correction circuit functions, and the circuit power factor can be measured. Through a variety of detection circuit, with the support SCM control. And 30V~36V output voltage regulator can be set; with over-current protection circuits function, and be able to automatically back. Output current, voltage, and little significant value are displayed by display modules.
Lorentz invariant relative velocity and relativistic binary collisions
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 Invariance Violation and Modified Hawking Fermions Tunneling Radiation
Directory of Open Access Journals (Sweden)
Shu-Zheng Yang
2016-01-01
Full Text Available Recently the modified Dirac equation with Lorentz invariance violation has been proposed, which would be helpful to resolve some issues in quantum gravity theory and high energy physics. In this paper, the modified Dirac equation has been generalized in curved spacetime, and then fermion tunneling of black holes is researched under this correctional Dirac field theory. We also use semiclassical approximation method to get correctional Hamilton-Jacobi equation, so that the correctional Hawking temperature and correctional black hole’s entropy are derived.
Fick's Law in a Random Lattice Lorentz Gas
Lefevere, Raphaël
2015-06-01
We provide a proof that the stationary macroscopic current of particles in a random lattice Lorentz gas satisfies Fick's law when connected to particles reservoirs. We consider a box on a d + 1-dimensional lattice and when , we show that under a diffusive rescaling of space and time, the probability of finding a current different from its stationary value is exponentially small in time. Its stationary value is given by the conductivity times the difference of chemical potentials of the reservoirs. The proof is based on the fact that in a high dimension, random walks have a small probability of making loops or intersecting each other when starting sufficiently far apart.
Tests of CPT, Lorentz invariance and the WEP with antihydrogen
Energy Technology Data Exchange (ETDEWEB)
Holzscheiter, M.H.; ATHENA Collaboration
1999-03-01
Antihydrogen atoms, produced near rest, trapped in a magnetic well, and cooled to the lowest possible temperature (kinetic energy) could provide an extremely powerful tool for the search of violations of CPT and Lorentz invariance. Equally well, such a system could be used for searches of violations of the Weak Equivalence Principle (WEP) at high precision. The author describes his plans to form a significant number of cold, trapped antihydrogen atoms for comparative precision spectroscopy of hydrogen and antihydrogen and comment on possible first experiments.
Lorentz invariant relative velocity and relativistic binary collisions
Cannoni, Mirco
2016-01-01
This article 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 non--physical 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 Covariant Canonical Symplectic Algorithms for Dynamics of Charged Particles
Wang, Yulei; Qin, Hong
2016-01-01
In this paper, the Lorentz covariance of algorithms is introduced. Under Lorentz transformation, both the form and performance of a Lorentz covariant algorithm are invariant. To acquire the advantages of symplectic algorithms and Lorentz covariance, a general procedure for constructing Lorentz covariant canonical symplectic algorithms (LCCSA) is provided, based on which an explicit LCCSA for dynamics of relativistic charged particles is built. LCCSA possesses Lorentz invariance as well as long-term numerical accuracy and stability, due to the preservation of discrete symplectic structure and Lorentz symmetry of the system. For situations with time-dependent electromagnetic fields, which is difficult to handle in traditional construction procedures of symplectic algorithms, LCCSA provides a perfect explicit canonical symplectic solution by implementing the discretization in 4-spacetime. We also show that LCCSA has built-in energy-based adaptive time steps, which can optimize the computation performance when th...
Search for anisotropic Lorentz invariance violation with {\\gamma}-rays
Kislat, Fabian
2015-01-01
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 behaviour of a more fundamental Grand Unified Theory, including Lorentz and CPT violating terms. In the SME the Lorentz violating operators can in part be classified by their mass-dimension d, with the...
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.
Lorentz Invariant CPT Violating Effects for a Class of Gauge-invariant Nonlocal Thirring Models
Patra, Pinaki
2013-01-01
CPT violation and Lorentz invariance can coexist in the framework of non-local field theory. Local gauge-invariance may not hold for the few non-local interaction terms. However, the gauge-invariance for the non-local interaction term can be formulated by the inclusion of Swinger non-integrable phase factor. In this article we have proposed a class of CPT violating Lorentz invariant Nonlocal Gauge-invariant models which can be termed as non-local gauge-invariant Thirring models. The inclusion of non-locality will modify the current conservation laws. Also, the possible particle antiparticle mass-splitting in this respect is discussed.
A Search for Lorentz Invariance and CPT Violation with the MINOS Far Detector
Adamson, P; 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
2010-01-01
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.
BPS Lorentz-violating vortex solutions
Energy Technology Data Exchange (ETDEWEB)
Casana, Rodolfo; Ferreira Junior, Manoel M. [Universidade Federal do Maranhao (UFMA), Sao Luis, MA (Brazil). Dept. de Fisica; Hora, E. da [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Departamento de Fisica
2011-07-01
In this work, we deal with the construction of static Bogomol'nyi-Prasad-Sommerfield (BPS) rotationally symmetric configurations on the dimensional CPT-even Lorentz-breaking photonic sector of the Standard Model Extension (SME). The main objective of this presentation is to show the possibility of obtaining such BPS solutions, even in the presence of a Lorentz-violating background. A secondary objective is to analyze the effects of this background on such topologically non-trivial BPS configurations. In order to obtain these results, we deal with some specific components of Lorentz-violating field, handling with the static Euler-Lagrange equation of motion to gauge field, from which we fix temporal gauge (absence of electric field) as a proper gauge choice. Also, considering this equation, we consistently determine an interesting configuration (discarding non-interesting ones) to the Lorentz-breaking sector. Using this configuration and the standard rotationally symmetric vortex Ansatz (which describes the behaviors of Higgs and gauge fields via two profile functions, g(r) and a(r), respectively), we construct a rotationally symmetric expression to the energy density of the system. To obtain BPS solutions, we rewrite this expression in order to have static vortex solutions satisfying a set of first order differential equations (BPS ones). The existence of such solutions is strongly constrained by a relation between some parameters of the model, including the Lorentz-breaking one. Naturally, we show that the total energy of these BPS solutions is proportional to their magnetic flux, which is quantized according to their winding number. Using suitable boundary conditions (near the origin and asymptotically), we numerically integrate the BPS equations (by means of the shooting method). By this way, we obtain solutions for some physical quantities (Higgs field, magnetic field and energy density) for several values of the Lorentz-violating parameters. From these
Influence of velocity profile on calibration function of Lorentz force flowmeter
Institute of Scientific and Technical Information of China (English)
C STELIAN; 于洋; 李木文; A THESS
2014-01-01
A Lorentz force flowmeter is a noncontact electromagnetic flow-measuring device based on exposing a flowing electrically conducting liquid to a magnetic field and measuring the force acting on the magnet system. The measured Lorentz force is proportional to the flow rate via a calibration coefficient which depends on the velocity distribution and magnetic field in liquid. In this paper, the influence of different velocity profiles on the calibration coefficient is investigated by using numerical simulations. The Lorentz forces are computed for laminar flows in closed and open rectangular channels, and the results are compared with the simplified case of a solid conductor moving at a constant velocity. The numerical computations demonstrate that calibration coefficients for solid bodies are always higher than for liquid metals. Moreover, it can be found that for some parameters the solid-body calibration coefficient is almost twice as high as for a liquid metal. These differences are explained by analyzing the patterns of the induced eddy currents and the spatial distributions of the Lorentz force density. The result provides a first step for evaluating the influence of the laminar velocity profiles on the calibration function of a Lorentz force flowmeter.
Gravitomagnetism and the Lorentz Invariance of Gravity
Kopeikin, S M
2006-01-01
Experimental discovery of the gravitomagnetic fields generated by translational and/or rotational currents of matter is one of primary goals of modern gravitational physics. The rotational (intrinsic) gravitomagnetic field of the Earth is currently measured by the Gravity Probe B. The present paper makes use of a parametrized post-Newtonian (PN) expansion of the Einstein equations to demonstrate how the extrinsic gravitomagnetic field generated by the translational current of matter can be measured by observing the relativistic time delay caused by a moving gravitational lens. We prove that measuring the extrinsic gravitomagnetic field is equivalent to testing of the relativistic effect of the aberration of gravity caused by the Lorentz transformation of the gravitational field. We unfold that the recent Jovian deflection experiment is a null-type experiment testing the Lorentz invariance of the gravitational field (aberration of gravity), thus, confirming existence of the extrinsic gravitomagnetic field asso...
Lorentz Transformation and General Covariance Principle
Kleyn, Aleks
2008-01-01
I tell about different mathematical tool that is important in general relativity. The text of the book includes definition of geometrical object, concept of reference frame, geometry of metric-affinne manifold. Using this concept I learn few physical applications: dynamics and Lorentz transformation in gravitational fields, Doppler shift. A reference frame in event space is a smooth field of orthonormal bases. Every reference frame is equipped by anholonomic coordinates. Using anholonomic coordinates allows to find out relative speed of two observers and appropriate Lorentz transformation. Synchronization of a reference frame is an anholonomic time coordinate. Simple calculations show how synchronization influences time measurement in the vicinity of the Earth. Measurement of Doppler shift from the star orbiting the black hole helps to determine mass of the black hole. We call a manifold with torsion and nonmetricity the metric\\hyph affine manifold. The nonmetricity leads to a difference between the auto para...
From scale invariance to Lorentz symmetry
Sibiryakov, Sergey
2014-01-01
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 presence of one or several Lorentz groups acting on the operator algebra of the theory.
The Lorentz anomaly via operator product expansion
Energy Technology Data Exchange (ETDEWEB)
Fredenhagen, Stefan, E-mail: stefan.fredenhagen@aei.mpg.de [Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut Am Mühlenberg 1, 14476 Golm (Germany); Hoppe, Jens, E-mail: hoppe@kth.se; Hynek, Mariusz, E-mail: mkhynek@kth.se [Department of Mathematics, Royal Institute of Technology, KTH 100 44 Stockholm (Sweden)
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.
Maxwell Duality, Lorentz Invariance, and Topological Phase
Dowling, J P; Franson, J D; Dowling, Jonathan P.; Williams, Colin P.
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. We also elucidate Lorentz transformations that allow these effects to be understood in an intuitive fashion in the rest frame of the moving quantum particle. Finally, we propose a realistic set up for measuring and interpreting the He-McKellar-Wilkens phase directly in an experiment.
Unravelling Lorentz Covariance and the Spacetime Formalism
Directory of Open Access Journals (Sweden)
Cahill R. T.
2008-10-01
Full Text Available We report the discovery of an exact mapping from Galilean time and space coordinates to Minkowski spacetime coordinates, showing that Lorentz covariance and the space-time construct are consistent with the existence of a dynamical 3-space, and absolute motion. We illustrate this mapping first with the standard theory of sound, as vibrations of a medium, which itself may be undergoing fluid motion, and which is covariant under Galilean coordinate transformations. By introducing a different non-physical class of space and time coordinates it may be cast into a form that is covariant under Lorentz transformations wherein the speed of sound is now the invariant speed. If this latter formalism were taken as fundamental and complete we would be lead to the introduction of a pseudo-Riemannian spacetime description of sound, with a metric characterised by an invariant speed of sound. This analysis is an allegory for the development of 20th century physics, but where the Lorentz covariant Maxwell equations were constructed first, and the Galilean form was later constructed by Hertz, but ignored. It is shown that the Lorentz covariance of the Maxwell equations only occurs because of the use of non-physical space and time coordinates. The use of this class of coordinates has confounded 20th century physics, and resulted in the existence of a allowing dynamical 3-space being overlooked. The discovery of the dynamics of this 3-space has lead to the derivation of an extended gravity theory as a quantum effect, and confirmed by numerous experiments and observations
Unravelling Lorentz Covariance and the Spacetime Formalism
Directory of Open Access Journals (Sweden)
Cahill R. T.
2008-10-01
Full Text Available We report the discovery of an exact mapping from Galilean time and space coordinates to Minkowski spacetime coordinates, showing that Lorentz covariance and the space- time construct are consistent with the existence of a dynamical 3-space, and “absolute motion”. We illustrate this mapping first with the standard theory of sound, as vibra- tions of a medium, which itself may be undergoing fluid motion, and which is covari- ant under Galilean coordinate transformations. By introducing a different non-physical class of space and time coordinates it may be cast into a form that is covariant under “Lorentz transformations” wherein the speed of sound is now the “invariant speed”. If this latter formalism were taken as fundamental and complete we would be lead to the introduction of a pseudo-Riemannian “spacetime” description of sound, with a metric characterised by an “invariant speed of sound”. This analysis is an allegory for the development of 20th century physics, but where the Lorentz covariant Maxwell equa- tions were constructed first, and the Galilean form was later constructed by Hertz, but ignored. It is shown that the Lorentz covariance of the Maxwell equations only occurs because of the use of non-physical space and time coordinates. The use of this class of coordinates has confounded 20th century physics, and resulted in the existence of a “flowing” dynamical 3-space being overlooked. The discovery of the dynamics of this 3-space has lead to the derivation of an extended gravity theory as a quantum effect, and confirmed by numerous experiments and observations
Extended Lorentz code of a superluminal particle
Ter-Kazarian, G
2012-01-01
While the OPERA experimental scrutiny is ongoing in the community, in the present article we construct a toy model of {\\it extended Lorentz code} (ELC) of the uniform motion, which will be a well established consistent and unique theoretical framework to explain the apparent violations of the standard Lorentz code (SLC), the possible manifestations of which arise in a similar way in all particle sectors. We argue that in the ELC-framework the propagation of the superluminal particle, which implies the modified dispersion relation, could be consistent with causality. Furthermore, in this framework, we give a justification of forbiddance of Vavilov-Cherenkov (VC)-radiation/or analog processes in vacuum. To be consistent with the SN1987A and OPERA data, we identify the neutrinos from SN1987A and the light as so-called {\\it 1-th type} particles carrying the {\\it individual Lorentz motion code} with the velocity of light $c_{1}\\equiv c$ in vacuum as maximum attainable velocity for all the 1-th type particles. Ther...
The CTA Sensitivity to Lorentz-Violating Effects on the Gamma-Ray Horizon
Fairbairn, Malcolm; Ellis, John; Hinton, Jim; White, Richard
2014-01-01
The arrival of TeV-energy photons from distant galaxies is expected to be affected by their QED interaction with intergalactic radiation fields through electron-positron pair production. In theories where high-energy photons violate Lorentz symmetry, the kinematics of the process $\\gamma + \\gamma\\rightarrow e^+ + e^-$ is altered and the cross-section suppressed. Consequently, one would expect more of the highest-energy photons to arrive if QED is modified by Lorentz violation than if it is not. We estimate the sensitivity of Cherenkov Telescope Array (CTA) to changes in the $\\gamma$-ray horizon of the Universe due to Lorentz violation, and find that it should be competitive with other leading constraints.
On the use of energy loss mechanisms to constrain Lorentz invariance violations
Mazón, Diego
2014-01-01
In light of recent and probably incoming observations of very high energy astroparticles, such as those reported by the IceCube collaboration, we readdress the energy loss mechanism by Lorentz violating particles. We analytically show that Cohen-Glashow's formula for energy loss is connected with a Poisson distribution for the number of decays, whose large fluctuations prevent from placing bounds on Lorentz invariance violations. However, this model ignores the sharp change in the decay width after each process. We propose replacing Poisson statistics with a new distribution that takes this into account. We study the average final energy and its fluctuations according to the new statistics, contrasting it with Cohen-Glashow's result and discussing the reliability of energy loss mechanisms to constrain violations of Lorentz invariance.
Borges, L H C; Barone, F A
2016-01-01
This paper is dedicated to the study of interactions between external sources for the electromagnetic field in a Lorentz symmetry breaking scenario. We focus on a particular higher derivative, Lorentz violating interaction that arises from a specific model that was argued to lead to interesting effects in the low energy phenomenology of light pseudoscalars interacting with photons. The kind of higher derivative Lorentz violating interaction we discuss do not appear in the well known Standard Model Extension, therefore they are called nonminimal. They are usually expected to be relevant only at very high energies, but we argue they might also induce relevant effects in low energy phenomena. Special attention is given for phenomena that have no counterpart in Maxwell theory.
Search for a Lorentz-violating sidereal signal with atmospheric neutrinos in IceCube
Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; Benzvi, S.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Bose, D.; Böser, S.; Botner, O.; Braun, J.; Buitink, S.; Carson, M.; Chirkin, D.; Christy, B.; Clem, J.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D. F.; D'Agostino, M. V.; Danninger, M.; Davis, J. C.; de Clercq, C.; Demirörs, L.; Depaepe, O.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; Deyoung, T.; Díaz-Vélez, J. C.; Dierckxsens, M.; Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Ehrlich, R.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feusels, T.; Filimonov, K.; Finley, C.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Geisler, M.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Goodman, J. A.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gurtner, M.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Helbing, K.; Herquet, P.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Homeier, A.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Joseph, J. M.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kelley, J. L.; Kemming, N.; Kenny, P.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Koskinen, D. J.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Krings, T.; Kroll, G.; Kuehn, K.; Kuwabara, T.; Labare, M.; Lafebre, S.; Laihem, K.; Landsman, H.; Larson, M. J.; Lauer, R.; Lehmann, R.; Lünemann, J.; Madsen, J.; Majumdar, P.; Marotta, A.; Maruyama, R.; Mase, K.; Matis, H. S.; Matusik, M.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Middell, E.; Milke, N.; Miller, J.; Montaruli, T.; Morse, R.; Movit, S. M.; Nahnhauer, R.; Nam, J. W.; Naumann, U.; Nießen, P.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; O'Murchadha, A.; Ono, M.; Panknin, S.; Paul, L.; Pérez de Los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Porrata, R.; Posselt, J.; Price, P. B.; Prikockis, M.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Rodrigues, J. P.; Roth, P.; Rothmaier, F.; Rott, C.; Ruhe, T.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Santander, M.; Sarkar, S.; Schatto, K.; Schlenstedt, S.; Schmidt, T.; Schukraft, A.; Schultes, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Singh, K.; Slipak, A.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stephens, G.; Stezelberger, T.; Stokstad, R. G.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sullivan, G. W.; Swillens, Q.; Taavola, H.; Taboada, I.; Tamburro, A.; Tarasova, O.; Tepe, A.; Ter-Antonyan, S.; Tilav, S.; Toale, P. A.; Toscano, S.; Tosi, D.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; van Overloop, A.; van Santen, J.; Voge, M.; Voigt, B.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Weaver, Ch.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Wikström, G.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Wolf, M.; Woschnagg, K.; Xu, C.; Xu, X. W.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.
2010-12-01
A search for sidereal modulation in the flux of atmospheric muon neutrinos in IceCube was performed. Such a signal could be an indication of Lorentz-violating physics. Neutrino oscillation models, derivable from extensions to the standard model, allow for neutrino oscillations that depend on the neutrino’s direction of propagation. No such direction-dependent variation was found. A discrete Fourier transform method was used to constrain the Lorentz and CPT-violating coefficients in one of these models. Because of the unique high energy reach of IceCube, it was possible to improve constraints on certain Lorentz-violating oscillations by 3 orders of magnitude with respect to limits set by other experiments.
Search for a Lorentz-violating sidereal signal with atmospheric neutrinos in IceCube
Energy Technology Data Exchange (ETDEWEB)
IceCube; etal, Abbasi, R,
2010-11-11
A search for sidereal modulation in the flux of atmospheric muon neutrinos in IceCube was performed. Such a signal could be an indication of Lorentz-violating physics. Neutrino oscillationmodels, derivable from extensions to the Standard Model, allow for neutrino oscillations that depend on the neutrino's direction of propagation. No such direction-dependent variation was found. Adiscrete Fourier transform method was used to constrain the Lorentz and CPT-violating coefficients in one of these models. Due to the unique high energy reach of IceCube, it was possible to improveconstraints on certain Lorentz-violating oscillations by three orders of magnitude with respect to limits set by other experiments.
Search for a Lorentz-violating sidereal signal with atmospheric neutrinos in IceCube
Abbasi, R; Abu-Zayyad, T; Adams, J; Aguilar, J A; Ahlers, M; Andeen, K; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Bay, R; Alba, J L Bazo; Beattie, K; Beatty, J J; Bechet, S; Becker, J K; Becker, K -H; Benabderrahmane, M L; BenZvi, S; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bertrand, D; Besson, D Z; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohm, C; Bose, D; Böser, S; Botner, O; Braun, J; Buitink, S; Carson, M; Chirkin, D; Christy, B; Clem, J; Clevermann, F; Cohen, S; Colnard, C; Cowen, D F; D'Agostino, M V; Danninger, M; Davis, J C; De Clercq, C; Demirörs, L; Depaepe, O; Descamps, F; Desiati, P; de Vries-Uiterweerd, G; DeYoung, T; Díaz-Vélez, J C; Dierckxsens, M; Dreyer, J; Dumm, J P; Duvoort, M R; Ehrlich, R; Eisch, J; Ellsworth, R W; Engdegård, O; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feusels, T; Filimonov, K; Finley, C; Foerster, M M; Fox, B D; Franckowiak, A; Franke, R; Gaisser, T K; Gallagher, J; Geisler, M; Gerhardt, L; Gladstone, L; Glüsenkamp, T; Goldschmidt, A; Goodman, J A; Grant, D; Griesel, T; Groß, A; Grullon, S; Gurtner, M; Ha, C; Hallgren, A; Halzen, F; Han, K; Hanson, K; Helbing, K; Herquet, P; Hickford, S; Hill, G C; Hoffman, K D; Homeier, A; Hoshina, K; Hubert, D; Huelsnitz, W; Hülß, J -P; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobsen, J; Japaridze, G S; Johansson, H; Joseph, J M; Kampert, K -H; Karg, T; Karle, A; Kelley, J L; Kemming, N; Kenny, P; Kiryluk, J; Kislat, F; Klein, S R; Köhne, J -H; Kohnen, G; Kolanoski, H; Köpke, L; Koskinen, D J; Kowalski, M; Kowarik, T; Krasberg, M; Krings, T; Kroll, G; Kuehn, K; Kuwabara, T; Labare, M; Lafebre, S; Laihem, K; Landsman, H; Larson, M J; Lauer, R; Lehmann, R; Lünemann, J; Madsen, J; Majumdar, P; Marotta, A; Maruyama, R; Mase, K; Matis, H S; Matusik, M; Meagher, K; Merck, M; Mészáros, P; Meures, T; Middell, E; Milke, N; Miller, J; Montaruli, T; Morse, R; Movit, S M; Nahnhauer, R; Nam, J W; Naumann, U; Nießen, P; Nygren, D R; Odrowski, S; Olivas, A; Olivo, M; O'Murchadha, A; Ono, M; Panknin, S; Paul, L; Heros, C Pérez de los; Petrovic, J; Piegsa, A; Pieloth, D; Porrata, R; Posselt, J; Price, P B; Prikockis, M; Przybylski, G T; Rawlins, K; Redl, P; Resconi, E; Rhode, W; Ribordy, M; Rizzo, A; Rodrigues, J P; Roth, P; Rothmaier, F; Rott, C; Ruhe, T; Rutledge, D; Ruzybayev, B; Ryckbosch, D; Sander, H -G; Santander, M; Sarkar, S; Schatto, K; Schlenstedt, S; Schmidt, T; Schukraft, A; Schultes, A; Schulz, O; Schunck, M; Seckel, D; Semburg, B; Seo, S H; Sestayo, Y; Seunarine, S; Silvestri, A; Singh, K; Slipak, A; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stephens, G; Stezelberger, T; Stokstad, R G; Stoyanov, S; Strahler, E A; Straszheim, T; Sullivan, G W; Swillens, Q; Taavola, H; Taboada, I; Tamburro, A; Tarasova, O; Tepe, A; Ter-Antonyan, S; Tilav, S; Toale, P A; Toscano, S; Tosi, D; Turčan, D; van Eijndhoven, N; Vandenbroucke, J; Van Overloop, A; van Santen, J; Voge, M; Voigt, B; Walck, C; Waldenmaier, T; Wallraff, M; Walter, M; Weaver, Ch; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Wikström, G; Williams, D R; Wischnewski, R; Wissing, H; Wolf, M; Woschnagg, K; Xu, C; Xu, X W; Yodh, G; Yoshida, S; Zarzhitsky, P
2010-01-01
A search for sidereal modulation in the flux of atmospheric muon neutrinos in IceCube was performed. Such a signal could be an indication of Lorentz-violating physics. Neutrino oscillation models, derivable from extensions to the Standard Model, allow for neutrino oscillations that depend on the neutrino's direction of propagation. No such direction-dependent variation was found. A discrete Fourier transform method was used to constrain the Lorentz and CPT-violating coefficients in one of these models. Due to the unique high energy reach of IceCube, it was possible to improve constraints on certain Lorentz-violating oscillations by three orders of magnitude with respect to limits set by other experiments.
Ultra-large distance modification of gravity from Lorentz symmetry breaking at the Planck scale
Gorbunov, D S
2005-01-01
We present an extension of the Randall--Sundrum model in which, due to spontaneous Lorentz symmetry breaking, graviton mixes with bulk vector fields and becomes quasilocalized. The masses of KK modes comprising the four-dimensional graviton are naturally exponentially small. This allows to push the Lorentz breaking scale to as high as a few tenth of the Planck mass. The model does not contain ghosts or tachyons and does not exhibit the van Dam--Veltman--Zakharov discontinuity. The gravitational attraction between static point masses becomes gradually weaker with increasing of separation and gets replaced by repulsion (antigravity) at exponentially large distances.
Institute of Scientific and Technical Information of China (English)
徐宽
2000-01-01
百年以前，由洛伦兹建立的电磁场对电荷的作用力公式-洛伦兹力公式，是在低速情况下得到的，后来被推广到了任意运动速度。本文根据一般电磁场理论讨论了运动电荷的电磁场特性，认为该公式只适用于低速情况，对高速运动电荷不再适用。并在此基础上导出了适用于任意速度的新的洛伦兹力公式，它在低速情况下转化为通常的洛伦兹力公式。%One hundred years ago,the formula offorce on acharge in electromagnetic field was established by Lorentz in the case of a charge at lower speed.That formula was extended for charge at any speed afterwards.In present paper,the character of electromagnetic field of a moving charge has been discussed by general theory ofM electromagnetic field.And then a different view has been pointed out,i.e.that formula is only suitable for the case of a char-ge at lower speed other than that at high speed.The new form of Lorentz Force Formula,that will be suitable for the charge at any speed,has been derived,and it can be transformed into the general Lorentz Force Formula in any case at lower speed.
Possible cosmogenic neutrino constraints on Planck-scale Lorentz violation
Energy Technology Data Exchange (ETDEWEB)
Mattingly, David M. [New Hamshire Univ., Durham, NH (United States); Maccione, Luca [DESY Hamburg (Germany). Theory Group; Galaverni, Matteo [INAF-IASF Bologna (Italy); Liberati, Stefano [INFN, Trieste (Italy); SISSA, Trieste (Italy); Sigl, Guenter [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik
2009-11-15
We study, within an effective field theory framework, O(E{sup 2}/M{sup 2}{sub Pl}) Planck-scale suppressed Lorentz invariance violation (LV) effects in the neutrino sector, whose size we parameterize by a dimensionless parameter {eta}{sub {nu}}. 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 {eta}{sub {nu}}
Generalized Lorentz invariance with an invariant energy scale
Magueijo, J; Magueijo, Joao; Smolin, Lee
2003-01-01
The hypothesis that the Lorentz transformations may be modified at Planck scale energies is further explored. We present a general formalism for theories which preserve the relativity of inertial frames with a non-linear action of the Lorentz transformations on momentum space. Several examples are discussed in which the speed of light varies with energy and elementary particles have a maximum momenta and/or energy. Energy and momentum conservation are suitably generalized and a proposal is made for how the new transformation laws apply to composite systems. We then use these results to explain the ultra high energy cosmic ray anomaly and we find a form of the theory that explains the anomaly, and leads also to a maximum momentum and a speed of light that diverges with energy. We finally propose that the spatial coordinates be identified as the generators of translation in Minkowski spacetime. In some examples this leads to a commutative geometry, but with an energy dependent Planck constant.
Alkhalil, Shatha; Kolesnikov, Yurii; Thess, André
2015-11-01
In this paper, a novel method to measure the electrical conductivity of solid and molten metals is described. We term the method ‘Lorentz force sigmometry’, where the term ‘sigmometry’ refers to the letter sigma σ, often used to denote the electrical conductivity. The Lorentz force sigmometry method is based on the phenomenon of eddy currents generation in a moving conductor exposed to a magnetic field. Based on Ampere’s law, the eddy currents in turn generate a secondary magnetic field; as a result, the Lorentz force acts to brake the conductor. Owing to Newton’s third law, a measurable force, which is equal to the Lorentz force and is directly proportional to the electrical conductivity of the conductive fluid or solid, acts on the magnet. We present the results of the measurements performed on solids along with the initial measurements on fluids with a eutectic alloy composition of Ga67In20.5Sn12.5; detailed measurements on molten metals are still in progress and will be published in the future. We conducted a series of experiments and measured the properties of known electrical conductive metals, including aluminum and copper, to compute the calibration factor of the device, and then used the same calibration factor to estimate the unknown electrical conductivity of a brass bar. The predicted electrical conductivity of the brass bar was compared with the conductivity measured with a commercial device called ‘SigmaTest’ the observed error was less than 0.5%.
Lorentz symmetry breaking effects on relativistic EPR correlations
Energy Technology Data Exchange (ETDEWEB)
Belich, H. [Universidade Federal do Espirito Santo, Departamento de Fisica e Quimica, Vitoria, ES (Brazil); Furtado, C.; Bakke, K. [Universidade Federal da Paraiba, Departamento de Fisica, Caixa Postal 5008, Joao Pessoa, PB (Brazil)
2015-09-15
Lorentz symmetry breaking effects on relativistic EPR (Einstein-Podolsky-Rosen) correlations are discussed. From the modified Maxwell theory coupled to gravity, we establish a possible scenario of the Lorentz symmetry violation and write an effective metric for the Minkowski spacetime. Then we obtain the Wigner rotation angle via the Fermi-Walker transport of spinors and consider the WKB (Wentzel-Kramers-Brillouin) approximation in order to study the influence of Lorentz symmetry breaking effects on the relativistic EPR correlations. (orig.)
A CPT-even and Lorentz-Violating nonminimal coupling in the Dirac equation
Energy Technology Data Exchange (ETDEWEB)
Ferreira Junior, Manoel; Casana, M.R.; Santos, Frederico E.P. dos; Silva, E.O. [UFMA, Sao Luis (Brazil); Passos, E. [UFCG, Campina Grande, PB (Brazil)
2013-07-01
Full text: The Standard Model Extension (SME) has been the usual framework for investigating signals of Lorentz violation in physical systems. It is the natural framework for studying properties of physical systems with Lorentz-violation since it includes Lorentz-violating terms in all sectors of the minimal standard model. The Lorentz-violating (LV) terms are generated as vacuum expectation values of tensors defined in a high energy scale. This framework has inspired a great deal of investigation in recent years. Such works encompass several distinct aspects involving fermion systems and radiative corrections, CPT- probing experiments, the electromagnetic CPT- and Lorentz-odd term, the 19 electromagnetic CPT-even coefficients. Recently, some studies involving higher dimensional operators have also been reported with great interest, including nonminimal interactions. These many contributions have elucidated the effects induced by Lorentz violation and served to set up stringent upper bounds on the LV coefficients. In the present work, we propose a new CPT-even, dimension-five, nonminimal coupling linking the fermionic and gauge fields in the context of the Dirac equation, involving the CPT-even tensor of the gauge term of the SME. By considering the nonrelativistic limit of the modified Dirac equation, we explicitly evaluate the new contributions to the nonrelativistic Hamiltonian. These new terms imply a direct correction on the anomalous magnetic moment, a kind of electrical Zeeman-like effect on the atomic spectrum, and a Rashba-like coupling term. These effects are then used to impose upper bounds on the magnitude of the non minimally coupled LV coefficients at the level of 1 part in 10{sub 16}. (author)
Lorentz-violating spinor electrodynamics and Penning traps
Ding, Yunhua
2016-01-01
The prospects are explored for testing Lorentz- and CPT-violating quantum electrodynamics in experiments with Penning traps. We present the Lagrange density of Lorentz-violating spinor electrodynamics with operators of mass dimensions up to six, and we discuss some of its properties. The theory is used to derive Lorentz- and CPT-violating perturbative shifts of the energy levels of a particle confined to a Penning trap. Observable signals are discussed for trapped electrons, positrons, protons, and antiprotons. Existing experimental measurements on anomaly frequencies are used to extract new or improved bounds on numerous coefficients for Lorentz and CPT violation, using sidereal variations of observables and comparisons between particles and antiparticles.
Prokopidis, Konstantinos; Kalialakis, Christos
2014-10-01
It is proposed that a recently used ad hoc modified Lorentz dielectric function for metals can be physically interpreted via the Lorentz-Dirac force. The Lorentz-Dirac force considers the radiation reaction of electrons, an effect that is ignored in classical dispersion relationships. A suitable reduced order form of the Lorentz-Dirac force that does not suffer from pre-acceleration and runaway artifacts is employed in the derivation of the modified dispersion model. The frequency characteristics and the causality of the Lorentz-Dirac dielectric model are studied in detail. Furthermore, the superiority of the Lorentz-Dirac dielectric function as a means of improved fitting of experimental data is demonstrated for gold, silver, and silicon in the infrared and optical region.
Lorentz Invariance Violation in Modified Gravity
Brax, Philippe
2012-01-01
We consider an environmentally dependent violation of Lorentz invariance in scalar-tensor models of modified gravity where General Relativity is retrieved locally thanks to a screening mechanism. We find that fermions have a modified dispersion relation and would go faster than light in an anisotropic and space-dependent way along the scalar field lines of force. We analyse briefly the OPERA results and show that they could be reproduced with chameleon models. We suggest that neutrinos emitted radially, at different energies, and observed on the other side of the earth would provide a test of these models.
Testing Lorentz invariance in β decay
Directory of Open Access Journals (Sweden)
Sytema A.
2014-03-01
Experimentally we exploit the Gamow-Teller transition of polarized 20Na, where we can test the dependence of the β-decay rate on the spin orientation of 20Na. The polarization degree is measured using the β asymmetry, while the decay rate is measured by the γ yield. A change in the γ rate, when reversing the spin, implies Lorentz invariance violation. The decay rate should depend on sidereal time and the polarization direction relative to the rotation axis of the earth. The method of the measurement will be presented, together with the first results.
New Limits on Local Lorentz Invariance in Mercury and Cesium
Peck, S K; Stein, D; Orbaker, D; Foss, A; Hummon, M T; Hunter, L R
2012-01-01
We report new bounds on Local Lorentz Invariance (LLI) violation in Cs and Hg. The limits are obtained through the observation of the the spin- precession frequencies of 199Hg and 133Cs atoms in their ground states as a function of the orientation of an applied magnetic field with respect to the fixed stars. We measure the amplitudes of the dipole couplings to a preferred direction in the equatorial plane to be 19(11) nHz for Hg and 9(5) microHz for Cs. The upper bounds established here improve upon previous bounds by about a factor of four. The improvement is primarily due to mounting the apparatus on a rotating table. New bounds are established on several terms in the standard model extension including the first bounds on the spin-couplings of the neutron and proton to the z direction, <7e-30 GeV and <7e-29 GeV, respectively.
Perepelitsa, Vassili F
2016-01-01
Some features of a Lorentz-violating (but Lorentz-covariant) Lagrangian of a scalar tachyon field are considered in this note. It is shown that the equation of motion and the Feynman propagator resulting from it are Lorentz-invariant, while the Lorentz symmetry of the suggested tachyon field model can be defined as spontaneously broken.
An operational approach to spacetime symmetries: Lorentz transformations from quantum communication
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.
The potential of the HAWC Observatory to observe violations of Lorentz Invariance
Nellen, Lukas
2015-01-01
The framework of relativistic quantum-field theories requires Lorentz Invariance. Many theories of quantum gravity, on the other hand, include violations of Lorentz Invariance at small scales and high energies. This generates a lot of interest in establishing limits on such effects, and, if possible, observing them directly. Gamma-ray observatories provide a tool to probe parts of the parameter space of models of Lorentz Invariance Violation that is not accessible in terrestrial laboratories and man-made accelerators. Transients, especially gamma-ray bursts, are a particularly promising class of events to search for such phenomena. By combining cosmological distances with high energy emission and short duration, emitting photons up to 30 GeV in less than a second, one can measure the energy dependence of the speed of photons to one part in $10^{16}$. We will discuss the potential of HAWC to detect effects of the violation of Lorentz Invariance and place its sensitivity in the context of existing limits.
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Test of Lorentz Invarience from Compton Scattering
Mohanmurthy, Prajwal; Narayan, Amrendra
2015-01-01
In the recent times, test of Lorentz Invariance has been used as a means to probe theories of physics beyond the standard model, especially those such as extensions to String Theory and Quantum Gravity. Tests of Lorentz invariance could go a long way in setting the stage for possible quantum gravity theories which are beyond the standard model. We describe a simple way of utilizing the polarimeters, which are a critical beam instrument at precision and intensity frontier nuclear physics labs such as Stanford Linear Accelerator Center (SLAC) and Jefferson Lab (JLab), to limit the dependence of speed of light with the energy of the photons. Furthermore, we also describe a way of limiting directional dependence of speed of light at previously unprecedented levels of precision by studying the sidereal variations. We obtain a limit of MSME parameters: $\\sqrt{\\kappa_X^2 + \\kappa_Y^2} < 2.4 \\times 10^{-17}$ and $\\sqrt{\\left( 2c_{TX} - (\\tilde{\\kappa}_{0^+}^{YZ} \\right)^2 + \\left( 2c_{TY} - (\\tilde{\\kappa}_{0^+}^{...
Cosmological constraints on Lorentz violating dark energy
Audren, B; Lesgourgues, J; Sibiryakov, S
2013-01-01
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 ThetaCDM, and study its cosmological implications in detail. At the background level, this model cannot be distinguished from LambdaCDM. The differences appear at the level of perturbations. We show that in ThetaCDM, 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 ...
Testing Lorentz symmetry with Lunar Laser Ranging
Bourgoin, A; Bouquillon, S; Poncin-Lafitte, C Le; Francou, G; Angonin, M -C
2016-01-01
Lorentz symmetry violations can be parametrized by an effective field theory framework that contains both General Relativity (GR) 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 20721 normal points covering the period August 1969 to December 2013. We emphasize that linear combination of SME coefficients to which LLR data are sensitive are not the same as those fitted in previous post-fit residuals analysis using LLR observations and based on theoretical grounds. We found no evidence for Lorentz violation at the level of $10^{-8}$ for $\\bar{s}^{TX}$, $10^{-12}$ for $\\bar{s}^{XY}$ and $\\bar{s}^{XZ}$, $10^{-11}$ for $\\bar{s}^{XX}-\\bar{s}^{YY}$ and $\\bar{s}^{XX}+\\bar{s}^{YY}-2\\bar{s}^{ZZ}-0.045\\bar{s}^{YZ}$ and $10^{-9}$ for $\\bar{s}^{TY}+...
QCD breaks Lorentz invariance and colour
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.
Quantizations of D = 3 Lorentz symmetry
Energy Technology Data Exchange (ETDEWEB)
Lukierski, J. [University of Wroclaw, Institute for Theoretical Physics, Wroclaw (Poland); Tolstoy, V.N. [University of Wroclaw, Institute for Theoretical Physics, Wroclaw (Poland); Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow (Russian Federation)
2017-04-15
Using the isomorphism o(3; C) ≅ sl(2; C) we develop a new simple algebraic technique for complete classification of quantum deformations (the classical r-matrices) for real forms o(3) and o(2,1) of the complex Lie algebra o(3; C) in terms of real forms of sl(2; C): su(2), su(1,1) and sl(2; R). We prove that the D = 3 Lorentz symmetry o(2,1) ≅ su(1,1) ≅ sl(2; R) has three different Hopf-algebraic quantum deformations, which are expressed in the simplest way by two standard su(1,1) and sl(2; R) q-analogs and by simple Jordanian sl(2; R) twist deformation. These quantizations are presented in terms of the quantum Cartan-Weyl generators for the quantized algebras su(1,1) and sl(2; R) as well as in terms of quantum Cartesian generators for the quantized algebra o(2,1). Finally, some applications of the deformed D = 3 Lorentz symmetry are mentioned. (orig.)
Testing Lorentz Invariance with neutrino burst from supernova neutronization
Chakraborty, Sovan; Sigl, Günter
2012-01-01
Quantum-gravity (QG) effects might generate Lorentz invariance violation by the interaction of energetic particles with the foamy structure of the space-time. As a consequence, particles may not travel at the universal speed of light. We propose to constrain Lorentz invariance violation for energetic neutrinos exploiting the $\
Testing local Lorentz invariance with short-range gravity
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.
Lorentz violation in neutron decay and allowed nuclear beta decay
Noordmans, J. P.; Wilschut, H. W.; Timmermans, R. G. E.
2013-01-01
Background: The search for violations of Lorentz invariance is nowadays motivated by attempts to unify the standard model of particle physics with general relativity. Such theories of "quantum gravity" predict Lorentz-violating signals that could be detected in low-energy precision experiments. In
Limits on Lorentz violation from charged-pion decay
P. Noordmans, J.; K. Vos, K.
2014-01-01
Charged-pion decay offers many opportunities to study Lorentz violation. Using an effective field theory approach, we study Lorentz violation in the lepton, W-boson, and quark sectors and derive the differential pion-decay rate, including muon polarization. Using coordinate redefinitions we are able
Testing Lorentz and CPT Symmetries in Penning Traps
Ding, Yunhua
2016-01-01
A modified Dirac equation with general Lorentz- and CPT-violating operators in the electromagnetic field is studied. Constraints on and possible sensitivities to Lorentz-violating coefficients in the nonminimal sector up to mass-dimension six can be obtained by analyzing Penning-trap results involving anomaly frequencies.
Lorentz-Dirac equation and circularly moving charges
Comay, E.
1987-09-01
The Lorentz-Dirac equation of radiation reaction is tested in a system of circularly moving changes. It is shown that this equation together with the Lienard-Wiechert retarded fields is consistent with energy conservation. Therefore, in this particular experiment, any alternative expression of radiation reaction must agree with the Lorentz-Dirac equation.
Testing local Lorentz invariance with short-range gravity
Kostelecky, Alan
2016-01-01
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.
Negative refraction and positive refraction are not Lorentz covariant
Energy Technology Data Exchange (ETDEWEB)
Mackay, Tom G., E-mail: T.Mackay@ed.ac.u [School of Mathematics and Maxwell Institute for Mathematical Sciences, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom)] [NanoMM - Nanoengineered Metamaterials Group, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802-6812 (United States); Lakhtakia, Akhlesh, E-mail: akhlesh@psu.ed [NanoMM - Nanoengineered Metamaterials Group, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802-6812 (United States)
2009-12-28
Refraction into a half-space occupied by a pseudochiral omega material moving at constant velocity was studied by directly implementing the Lorentz transformations of electric and magnetic fields. Numerical studies revealed that negative refraction, negative phase velocity and counterposition are not Lorentz-covariant phenomenons in general.
Elastic Sturmian spirals in the Lorentz-Minkowski plane
Directory of Open Access Journals (Sweden)
Uçum Ali
2016-01-01
Full Text Available In this paper we consider some elastic spacelike and timelike curves in the Lorentz-Minkowski plane and obtain the respective vectorial equations of their position vectors in explicit analytical form. We study in more details the generalized Sturmian spirals in the Lorentz-Minkowski plane which simultaneously are elastics in this space.
In-depth Study on Cylinder Wake Controlled by Lorentz Force
Institute of Scientific and Technical Information of China (English)
张辉; 范宝春; 陈志华
2011-01-01
The underlying mechanisms of the electromagnetic control of cylinder wake are investigated and discussed.The effects of Lorentz force are found to be composed of two parts,one is its direct action on the cylinder(the wall Lorentz force)and the other is applied to the fluid(called the field Lorentz force)near the cylinder surface.Our results show that the wall Lorentz force can generate thrust and reduce the drag; the field Lorentz force increases the drag.However,the cylinder drag is dominated by the wall Lorentz force.In addition,the field Lorentz force above the upper surface decreases the lift,while the upper wall Lorentz force increases it.The total lift is dominated by the upper wall Lorentz force.%The underlying mechanisms of the electromagnetic control of cylinder wake are investigated and discussed. The effects of Lorentz force are found to be composed of two parts, one is its direct action on the cylinder (the wall Lorentz force) and the other is applied to the fluid (called the field Lorentz force) near the cylinder surface. Our results show that the wall Lorentz force can generate thrust and reduce the drag; the Geld Lorentz force increases the drag. However, the cylinder drag is dominated by the wall Lorentz force. In addition, the field Lorentz force above the upper surface decreases the lift, while the upper wall Lorentz force increases it. The total lift is dominated by the upper wall Lorentz force.
Attitude dynamics and control of spacecraft using geomagnetic Lorentz force
Abdel-Aziz, Yehia A
2014-01-01
The attitude stabilization of a charged rigid spacecraft in Low Earth Orbit (LEO) 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 magnetic field will be subject to perturbations from 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 the 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...
Lorentz- and CPT-violating extension of the standard model
Kostelecky, V A
1999-01-01
The formulation and some experimental implications of a general Lorentz-violating extension of the standard model are reviewed. The theory incorporates both CPT-preserving and CPT-breaking terms. It is otherwise a conventional quantum field theory, obtained under the assumption that Lorentz symmetry is spontaneously broken in an underlying model. The theory contains the usual standard-model gauge structure, and it is power-counting renormalizable. Energy and momentum are conserved. Despite the violation of Lorentz symmetry, the theory exhibits covariance under Lorentz transformations of the observer inertial frame. A general Lorentz-violating extension of quantum electrodynamics can be extracted. The standard-model extension implies potentially observable effects in a wide variety of experiments, including among others measurements on neutral-meson oscillations, comparative studies in Penning traps, spectroscopy of hydrogen and antihydrogen, bounds on cosmological birefringence, measurements of muon propertie...
Effective Theory Approach to the Spontaneous Breakdown of Lorentz Invariance
Armendariz-Picon, Cristian; Penco, Riccardo
2010-01-01
We generalize the coset construction of Callan, Coleman, Wess and Zumino to theories in which the Lorentz group is spontaneously broken down to one of its subgroups. This allows us to write down the most general low-energy effective Lagrangian in which Lorentz invariance is non-linearly realized, and to explore the consequences of broken Lorentz symmetry without having to make any assumptions about the mechanism that triggers the breaking. We carry out the construction both in flat space, in which the Lorentz group is a global spacetime symmetry, and in a generally covariant theory, in which the Lorentz group can be treated as a local internal symmetry. As an illustration of this formalism, we construct the most general effective field theory in which the rotation group remains unbroken, and show that the latter is just the Einstein-aether theory.
Discussion on Neutrino Oscillation and CPT/Lorentz Invariance Violation
Luo, Cui-Bai; Du, Yi-Lun; Wang, Yong-Long; Zong, Hong-Shi
2016-01-01
Depending on deformed canonical anticommutation relations, massless neutrino oscillation based on CPT /Lorentz invariance viol ation is discussed. It is found that the deformed canonical anti-commutation relations should satisfy the condition of new Moy al product and new non standard commutation relations. Furthermore, by comparing the neutrino experimental data and the above relations, we find that the orders of magnitude of noncommutative parameters or Lorentz invariant Violation parameters $\\mathi t{A}$ is not self-consistent. This means that the previous studies about Lorentz invariance violation in noncommutative field theory may not naturally explain massless neutrino oscillation. In other words, it should be impossible to explain neutrino os cillation by lorentz invariance violation. This conclusion is supported by the latest atmospheric neutrinos experimental resul ts from Super-Kamiokande Collaboration, which show that no evidence of Lorentz invariance violation on atmospheric neutrinos w as observe...
Lorentz violation for photons and ultrahigh-energy cosmic rays.
Galaverni, Matteo; Sigl, Günter
2008-01-18
Lorentz symmetry breaking at very high energies may lead to photon dispersion relations of the form omega2=k2+xink2(k/MPl)n with new terms suppressed by a power n of the Planck mass MPl. We show that first and second order terms of size |xi1|>orsimilar10(-14) and xi2
Bounding isotropic Lorentz violation using synchrotron losses at LEP
Altschul, Brett
2009-11-01
Some deviations from special relativity—especially isotropic effects—are most efficiently constrained using particles with velocities very close to 1. While there are extremely tight bounds on some of the relevant parameters coming from astrophysical observations, many of these rely on our having an accurate understanding of the dynamics of these high-energy sources. It is desirable to have reliable laboratory constraints on these same parameters. The fastest-moving particles in a laboratory were electrons and positrons at LEP. The energetics of the LEP beams were extremely well understood, and measurements of the synchrotron emission rate indicate that the isotropic Lorentz violation coefficient |κ˜tr-(4)/(3)c00| must be smaller than 5×10-15.
The electrodeless Lorentz force (ELF) thruster experimental facility
Weber, T. E.; Slough, J. T.; Kirtley, D.
2012-11-01
An innovative facility for testing high-power, pulsed plasmoid thrusters has been constructed to develop the electrodeless Lorentz force (ELF) thruster concept. It is equipped with a suite of diagnostics optimized to study the physical processes taking place within ELF and evaluate its propulsive utility including magnetic field, neutral gas, and plasma flux diagnostics, a method to determine energy flow into the plasma from the pulsed power systems, and a new type of ballistic pendulum, which enables thrust to be measured without the need for installing the entire propulsion system on a thrust stand. Variable magnetic fields allow controlled studies of plume expansion in a small-scale experiment and dielectric chamber walls reduce electromagnetic influences on plasma behavior and thruster operation. The unique capabilities of this facility enable novel concept development to take place at greatly reduced cost and increased accessibility compared to testing at large user-facilities.
Mechanical analogies for the Lorentz gauge, particles and antiparticles
Dmitriyev, V P
2000-01-01
An exact analogy of electromagnetic fields and particles can be found in mechanics of a turbulent ideal fluid with voids. The system is supposed to form a fine dispersion of voids in the fluid. This microscopically discontinuous medium is treated as a continuum. The turbulence is described in terms of the Reynolds stresses. Perturbations of the homogeneous isotropic turbulence are considered. For the high-energy low-pressure turbulence they are usually small. This entails the linearization of the Reynolds equations. The latter appear to be isomorphic to Maxwell's electromagnetic equations. The Lorentz gauge expresses the slight effective compressibility of the medium. A particle can be viewed as a cavity in the medium. A respective antiparticle is modeled with an agglomerate of the medium's material. Microscopically, these correspond to some nonlinear vortex formations in the "vortex sponge".
Factors Influencing High School Students' Career Aspirations
Tang, Mei; Pan, Wei; Newmeyer, Mark D.
2008-01-01
This article explores the factors influencing high school students' career aspirations with a study analyzing 141 high school students. The Social Cognitive Career Development Model was utilized to examine the interactive relationships among learning experiences, career self-efficacy, outcome expectations, career interests, and career choices. The…
Symmetry of the Lorentz boost: the relativity of colocality and Lorentz time contraction
Sharp, Jonathan C.
2016-09-01
Since the Lorentz boost is symmetric under exchange of x and ct, special relativistic phenomena will also manifest this symmetry. Firstly, simultaneity becomes paired with ‘colocality’ (‘at the same place’), and the ‘Relativity of Colocality’ becomes the dual to the well-known ‘Relativity of Simultaneity’. Further, Lorentz time contraction arises from reversal of the observation conditions pertaining to time dilation, expressible figuratively as ‘Moving clocks run slow, but moving time runs fast’. Symmetry also dictates that the most fundamental observational modes are: (1) the simultaneous observation of length, a process involving both the relativity of simultaneity and length contraction; and (2) the colocal measurement of duration, involving both the relativity of colocality and time contraction. Only the first of these modes is well known. The adoption of this symmetrical lexicon provides a necessary logical basis for interpretational studies of observation and measurement in special relativity.
On asymptotic flatness and Lorentz charges
Energy Technology Data Exchange (ETDEWEB)
Compere, Geoffrey [KdV Institute for Mathematics, Universiteit van Amsterdam (Netherlands); Dehouck, Francois; Virmani, Amitabh, E-mail: gcompere@uva.nl, E-mail: fdehouck@ulb.ac.be, E-mail: avirmani@ulb.ac.be [Physique Theorique et Mathematique, Universite Libre de Bruxelles, Bruxelles (Belgium)
2011-07-21
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.
Radio Astronomical Polarimetry and the Lorentz Group
Britton, M C
1999-01-01
In radio astronomy the polarimetric properties of radiation are often modified during propagation and reception. Effects such as Faraday rotation, receiver cross-talk, and differential amplification act to change the state of polarized radiation. A general description of such transformations is useful for the investigation of these effects and for the interpretation and calibration of polarimetric observations. Such a description is provided by the Lorentz group, which is intimately related to the transformation properties of polarized radiation. In this paper the transformations that commonly arise in radio astronomy are analyzed in the context of this group. This analysis is then used to construct a model for the propagation and reception of radio waves. The implications of this model for radio astronomical polarimetry are discussed.
Lorentz invariance with an invariant energy scale
Magueijo, J; Magueijo, Joao; Smolin, Lee
2002-01-01
We propose a modification of special relativity in which a physical energy, which may be the Planck energy, joins the speed of light as an invariant, in spite of a complete relativity of inertial frames and agreement with Einstein's theory at low energies. This is accomplished by a non-linear modification of the action of the Lorentz group on momentum space, generated by adding a dilatation to each boost in such a way that the Planck energy remains invariant. The associated algebra has unmodified structure constants, and we highlight the similarities between the group action found and a transformation previously proposed by Fock. We also discuss the resulting modifications of field theory and suggest a modification of the equivalence principle which determines how the new theory is embedded in general relativity.
Testing Lorentz symmetry with planetary orbital dynamics
Hees, Aurélien; Poncin-Lafitte, Christophe Le; Bourgoin, Adrien; Rivoldini, Attilio; Lamine, Brahim; Meynadier, Frédéric; Guerlin, Christine; Wolf, Peter
2015-01-01
Planetary ephemerides are a very powerful tool to constrain deviations from the theory of General Relativity 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.
Universal Gravitation as Lorentz-covariant Dynamics
Kauffmann, Steven Kenneth
2014-01-01
Einstein's equivalence principle implies that the acceleration of a particle in a "specified" gravitational field is independent of its mass. While this is certainly true to great accuracy for bodies we observe in the Earth's gravitational field, a hypothetical body of mass comparable to the Earth's would perceptibly cause the Earth to fall toward it, which would feed back into the strength as a function of time of the Earth's gravitational field affecting that body. In short, Einstein's equivalence principle isn't exact, but is an approximation that ignores recoil of the "specified" gravitational field, which sheds light on why general relativity has no clearly delineated native embodiment of conserved four-momentum. Einstein's 1905 relativity of course doesn't have the inexactitudes he unwittingly built into GR, so it is natural to explore a Lorentz-covariant gravitational theory patterned directly on electromagnetism, wherein a system's zero-divergence overall stress-energy, including all gravitational fee...
Recent Results on the Periodic Lorentz Gas
Golse, François
2009-01-01
The Drude-Lorentz model for the motion of electrons in a solid is a classical model in statistical mechanics, where electrons are represented as point particles bouncing on a fixed system of obstacles (the atoms in the solid). Under some appropriate scaling assumption -- known as the Boltzmann-Grad scaling by analogy with the kinetic theory of rarefied gases -- this system can be described in some limit by a linear Boltzmann equation, assuming that the configuration of obstacles is random [G. Gallavotti, [Phys. Rev. (2) vol. 185 (1969), 308]). The case of a periodic configuration of obstacles (like atoms in a crystal) leads to a completely different limiting dynamics. These lecture notes review several results on this problem obtained in the past decade as joint work with J. Bourgain, E. Caglioti and B. Wennberg.
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.
The Impact of Lorentz Violation on the Klein Tunneling Effect
Xiao, Zhi
2016-01-01
We discuss the impact of a tiny Lorentz-violating $b^\\mu$ term on the one dimensional motion of a Dirac particle scattering on a rectangular barrier. We assume the experiment is performed in a particular inertial frame, where the components of $b^\\mu$ are assumed constants. The results show that Lorentz-violation modification to the transmission rate depends on the observer Lorentz nature of $b^\\mu$. For a spacelike or lightlike $b^\\mu$ the induced resonant frequency shift depends on the polarization, while for timelike $b^\\mu$ there is essentially no modification.
On radiation reaction and the Abraham-Lorentz-Dirac equation
de Oca, Alejandro Cabo Montes
2013-01-01
It is underlined that the Lienard-Wiechert solutions indicate that after the external force is instantly removed from a small charged particle, the field in its close neighborhood becomes a Lorentz boosted Coulomb field. It suggests that the force of the self-field on the particle should instantaneously vanish after a sudden removal of the external force. A minimal modification of Abraham-Lorentz-Dirac equation is searched seeking to implement this property. A term assuring this behavior is added to the equation by maintaining Lorentz covariance and vanishing scalar product with the four-velocity. The simple Dirac constant force example does not show runaway acceleration.
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.
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.
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
Shao, Cheng-Gang; Tan, Wen-Hai; Yang, Shan-Qing; Luo, Jun; Tobar, Michael Edmund; Bailey, Quentin G; Long, J C; Weisman, E; Xu, Rui; Kostelecky, Alan
2016-01-01
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 $10^{-9}$ m$^2$, improving by an order of magnitude the sensitivity to numerous types of Lorentz violation involving quadratic curvature derivatives and curvature couplings.
Møller scattering and Lorentz-violating Z bosons
Fu, Hao; Lehnert, Ralf
2016-11-01
Lorentz-symmetry breakdown in weak-interaction physics is studied. In particular, the CPT-even Lorentz-violating contributions to the Z boson in the minimal Standard-Model Extension are considered, and in this context polarized electron-electron scattering is investigated. Corrections to the usual parity-violating asymmetry are determined at tree level. Together with available data, this result can be used to improve existing estimates for the Lorentz-violating kW coefficient by two orders of magnitude. Some implications for past and future experiments are mentioned.
Standard model with Lorentz and CPT violations in Finsler spacetime
Chang, Zhe
2012-01-01
Standard model with intrinsic Lorentz and CPT violations is proposed in a Finsler geometric framework. We present explicitly Lorentz and CPT--breaking Lagrangians of the matter fields and the gauge fields in locally Minkowski spacetime. The Lorentz invariance violation is found to be originated from the spacetime background deviating from the Minkowski one. Similarly, the CPT violation is determined by the behaviors of the locally Minkowski metric under the parity and time reversal operations. To help understanding phenomenologies, we compare the Finslerian model with the standard--model extension (SME) term by term at a first order approximation.
Composition of Lorentz Transformations in Terms of Their Generators
Martínez, F S J
2001-01-01
Two-forms in Minkowski space-time may be considered as generators of Lorentz transformations. Here, the covariant and general expression for the composition law (Baker-Campbell-Hausdorff formula) of two Lorentz transformations in terms of their generators is obtained. Every subalgebra of the Lorentz algebra of such generators, up to one, may be generated by a sole pair of generators. When the subalgebra is known, the above BCH formula for the two two-forms simplifies. Its simplified expressions for all such subalgebras are also given.
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).
Computer simulation of some dynamical properties of the Lorentz gas
Joslin, C. G.; Egelstaff, P. A.
1989-07-01
We carried out molecular dynamics simulations of a Lorentz gas, consisting of a lone hydrogen molecule moving in a sea of stationary argon atoms. A Lennard-Jones form was assumed for the H2-Ar potential. The calculations were performed at a reduced temperature K * = kT/ɛH 2-Ar = 4.64 and at reduced densities ρ *= ρ Arσ{Ar/3} in the range 0.074-0.414. The placement of Ar atoms was assumed to be random rather than dictated by equilibrium considerations. We followed the trajectories of many H2 molecules, each of which is assigned in turn a velocity given by the Maxwell-Boltzmann distribution at the temperature of the simulation. Solving the equations of motion classically, we obtained the translational part of the incoherent dynamic structure factor for the H2 molecule, S tr( q, ω). This was convoluted with the rotational structure factor S rot( q, ω) calculated assuming unhindered rotation to obtain the total structure factor S( q, ω). Our results agree well with experimental data on this function obtained by Egelstaff et al. At the highest density ( ρ *=0.414) we studied the dependence of S( q, ω) on system size (number of Ar atoms), number of H2 molecules for which trajectories are generated, and the length of time over which these trajectories are followed.
Extremely high Q-factor toroidal metamaterials
Basharin, Alexey A; Volsky, Nikita; Kafesaki, Maria; Economou, Eleftherios N; Ustinov, Alexey V
2016-01-01
We demonstrate that, owing to the unique topology of the toroidal dipolar mode, its electric/magnetic field can be spatially confined within subwavelength, externally accessible regions of the metamolecules, which makes the toroidal planar metamaterials a viable platform for high Q-factor resonators due to interfering toroidal and other dipolar modes in metamolecules.
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.
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).
Lorentz-violating effects in the Bose-Einstein condensation of an ideal bosonic gas
Casana, Rodolfo; da Silva, Kleber A. T.
2015-03-01
We have studied the effects of Lorentz-violation in the Bose-Einstein condensation (BEC) of an ideal boson gas, by assessing both the nonrelativistic and ultrarelativistic limits. Our model describes a massive complex scalar field coupled to a CPT-even and Lorentz-violating background. We first analyze the nonrelativistic case, at this level by using experimental data, we obtain upper-bounds for some LIV parameters. In the sequel, we have constructed the partition function for the relativistic ideal boson gas which to be able of a consistent description requires the imposition of severe restrictions on some LIV coefficients. In both cases, we have demonstrated that the LIV contributions are contained in an overall factor, which multiplies almost all thermodynamical properties. An exception is the fraction of the condensed particles.
Testing Lorentz Invariance and CPT Conservation with NuMI Neutrinos in the MINOS Near Detector
Adamson, P; 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; Böhm, J; Böhnlein, 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; Morfn, J; Mualem, L; Mufson, S; Murgia, S; Musser, J; Naples, D; Nelson, J K; Newman, i 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; Pavlovi, Z; Pawloski, G; Pearce, G F; Peck, C W; Petyt, cD 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
2008-01-01
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 a class of extensions to the Standard Model. 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 these extensions to the Standard Model lie between 0.01-1% of the maximum expected, assuming a suppression of these signatures by factor of $10^{-17}$. \\
Tests of Local Lorentz Invariance Violation of Gravity in the Standard-Model Extension with Pulsars
Shao, Lijing
2014-01-01
Standard-model extension (SME) is an effective field theory introducing all possible Lorentz-violating (LV) operators to the standard model (SM) and general relativity (GR). In the pure-gravity sector of minimal SME (mSME), nine coefficients describe dominant observable deviations from GR. We systematically implemented twenty-seven tests from thirteen 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 mSME 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 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 gravit...
Probes of Lorentz violation in neutrino propagation
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.
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.
CPT/Lorentz Invariance Violation and Quantum Field Theory
Arias, P; Gamboa-Rios, J; López-Sarrion, J; Méndez, F; Arias, Paola; Das, Ashok; Gamboa, Jorge; Lopez-Sarrion, Justo; Mendez, Fernando
2006-01-01
Analogies between the noncommutative harmonic oscillator and noncommutative fields are analyzed. Following this analogy we construct examples of quantum fields theories with explicit CPT and Lorentz symmetry breaking. Some applications to baryogenesis and neutrino oscillation are also discussed
Lorentz-violating Euler-Heisenberg effective action
Furtado, J
2014-01-01
In this work, we study the radiative generation of the Lorentz-violating Euler-Heisenberg action, in the weak field approximation. For this, we first consider a nonperturbative calculation in the coefficient $c_{\\mu\
Vacuum Photon Splitting in Lorentz-Violating Quantum Electrodynamics
Kostelecky, V A; Kostelecky, Alan; Pickering, Austin
2003-01-01
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.
THE HOMOTHETIC MOTIONS IN THE LORENTZ 3-SPACE
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
In this article, the properties of the homothetic motions in three-dimensional Lorentz space are investigated. Also, some geometric results between velocity and acceleration vectors of a point in a spatial motion are obtained.
Lorentz-violating spinor electrodynamics and Penning traps
Ding, Yunhua; Kostelecký, V. Alan
2016-09-01
The prospects are explored for testing Lorentz- and C P T -violating quantum electrodynamics in experiments with Penning traps. We present the Lagrange density of Lorentz-violating spinor electrodynamics with operators of mass dimensions up to 6, and we discuss some of its properties. The theory is used to derive Lorentz- and C P T -violating perturbative shifts of the energy levels of a particle confined to a Penning trap. Observable signals are discussed for trapped electrons, positrons, protons, and antiprotons. Existing experimental measurements on anomaly frequencies are used to extract new or improved bounds on numerous coefficients for Lorentz and C P T violation, using sidereal variations of observables and comparisons between particles and antiparticles.
Larmor and the Prehistory of the Lorentz Transformations
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)
The Lorentz-Dirac equation and the structure of spacetime
De Souza, M M
1995-01-01
A new interpretation of the causality implementation in the Lienard-Wiechert solution raises new doubts against the validity of the Lorentz-Dirac equation and the limits of validity of the Minkowski structure of spacetime.
Lorentz invariant CPT breaking in the Dirac equation
Fujikawa, Kazuo
2016-01-01
If one modifies the Dirac equation in momentum space to $[\\gamma^{\\mu}p_{\\mu}-m-\\Delta m(\\theta(p_{0})-\\theta(-p_{0})) \\theta(p_{\\mu}^{2})]\\psi(p)=0$, the symmetry of positive and negative energy eigenvalues is lifted by $m\\pm \\Delta m$ for a small $\\Delta m$. The mass degeneracy of the particle and antiparticle is thus lifted in a Lorentz invariant manner since the combinations $\\theta(\\pm p_{0})\\theta(p_{\\mu}^{2})$ with step functions are manifestly Lorentz invariant. We explain an explicit construction of this CPT breaking term in coordinate space, which is Lorentz invariant but non-local at a distance scale of the Planck length. The application of this Lorentz invariant CPT breaking mechanism to the possible mass splitting of the neutrino and antineutrino in the Standard Model is briefly discussed.
Lorentz-violating effects in three-dimensional $QED$
Bufalo, R
2014-01-01
Inspired in discussions presented lately regarding Lorentz-violating interaction terms in \\cite{13,6}, 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 $\\left( 2+1\\right) $-dimensional spacetime. We define the Lagrangian density with a Lorentz-violating interaction, where the the spacetime 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 spacetime dimensionality. With that in mind we expect that the spacetime 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.
Dynamics and control of Lorentz-augmented spacecraft relative motion
Yan, Ye; Yang, Yueneng
2017-01-01
This book develops a dynamical model of the orbital motion of Lorentz spacecraft in both unperturbed and J2-perturbed environments. It explicitly discusses three kinds of typical space missions involving relative orbital control: spacecraft hovering, rendezvous, and formation flying. Subsequently, it puts forward designs for both open-loop and closed-loop control schemes propelled or augmented by the geomagnetic Lorentz force. These control schemes are entirely novel and represent a significantly departure from previous approaches.
Tests of Lorentz Symmetry in Single Beta Decay
Directory of Open Access Journals (Sweden)
Jorge S. Díaz
2014-01-01
Full Text Available Low-energy experiments studying single beta decay can serve as sensitive probes of Lorentz invariance that can complement interferometric searches for deviations from this spacetime symmetry. Experimental signatures of a dimension-three operator for Lorentz violation which are unobservable in neutrino oscillations are described for the decay of polarized and unpolarized neutrons as well as for measurements of the spectral endpoint in beta decay.
Consistency analysis of a nonbirefringent Lorentz-violating planar model
Casana, Rodolfo; Moreira, Roemir P M
2011-01-01
In this work analyze the physical consistency of a nonbirefringent Lorentz-violating planar model via the analysis of the pole structure of its Feynman's propagators. The nonbirefringent planar model, obtained from the dimensional reduction of the CPT-even gauge sector of the standard model extension, is composed of a gauge and a scalar fields, being affected by Lorentz-violating (LIV) coefficients encoded in the symmetric tensor $\\kappa_{\\mu\
UHECR bounds on Lorentz violation in the photon sector
Klinkhamer, F. R.
2008-01-01
The aim of this brief review is to present a case study of how astrophysics data can be used to get bounds on Lorentz-violating parameters. For this purpose, a particularly simple Lorentz-violating modification of the Maxwell theory of photons is considered, which maintains gauge invariance, CPT, and renormalization. With a standard spin-one-half Dirac particle minimally coupled to this nonstandard photon, the resulting modified-quantum-electrodynamics model involves nineteen dimensionless "d...
Letter: On the Solutions of the Lorentz-Dirac Equation
Vogt, D.; Letelier, P. S.
2003-12-01
We discuss the unstable character of the solutions of the Lorentz-Dirac equation and stress the need of methods like order reduction to derive a physically acceptable equation of motion. The discussion is illustrated with the paradigmatic example of the non-relativistic harmonic oscillator with radiation reaction. We also illustrate the removal of the noncausal pre-acceleration with the introduction of a small correction in the Lorentz-Dirac equation.
The BTZ black hole as a Lorentz-flat geometry
Energy Technology Data Exchange (ETDEWEB)
Alvarez, Pedro D., E-mail: alvarez@physics.ox.ac.uk [Rudolf Peierls Centre for Theoretical Physics, University of Oxford (United Kingdom); Pais, Pablo, E-mail: pais@cecs.cl [Centro de Estudios Científicos (CECs), Av. Arturo Prat 514, Valdivia (Chile); Universidad Andrés Bello, Av. República 440, Santiago (Chile); Rodríguez, Eduardo, E-mail: eduarodriguezsal@unal.edu.co [Departamento de Matemática y Física Aplicadas, Universidad Católica de la Santísima Concepción, Concepción (Chile); Salgado-Rebolledo, Patricio, E-mail: pasalgado@udec.cl [Centro de Estudios Científicos (CECs), Av. Arturo Prat 514, Valdivia (Chile); Departamento de Física, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Physique Théorique et Mathématique, Université Libre de Bruxelles and International Solvay Institutes, Campus Plaine C.P. 231, B-1050 Bruxelles (Belgium); Zanelli, Jorge, E-mail: z@cecs.cl [Centro de Estudios Científicos (CECs), Av. Arturo Prat 514, Valdivia (Chile); Universidad Andrés Bello, Av. República 440, Santiago (Chile)
2014-11-10
It is shown that 2+1 dimensional anti-de Sitter spacetimes are Lorentz-flat. This means, in particular, that any simply-connected patch of the BTZ black hole solution can be endowed with a Lorentz connection that is locally pure gauge. The result can be naturally extended to a wider class of black hole geometries and point particles in three-dimensional spacetime.
Cavity tests of parity-odd Lorentz violations in electrodynamics
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.
Finsler-like structures from Lorentz-breaking classical particles
Russell, Neil
2015-01-01
A method is presented for deducing classical point-particle Lagrange functions corresponding to a class of quartic dispersion relations. Applying this to particles violating Lorentz symmetry in the minimal Standard-Model Extension leads to a variety of novel lagrangians in flat spacetime. Morphisms in these classical systems are studied that echo invariance under field redefinitions in the quantized theory. The Lagrange functions found offer new possibilities for understanding Lorentz-breaking effects by exploring parallels with Finsler-like geometries.
Lorentz microscopy on dynamically written domains in GdTbFe
Energy Technology Data Exchange (ETDEWEB)
Greidanus, F.J.A.M.; Jacobs, B.A.J.; den Broeder, F.J.A.; Spruit, J.H.M.; Rosenkranz, M.
1989-03-06
In this letter a new method for the observation of thermomagnetically written domains using Lorentz electron microscopy is discussed. Domains are written in a GdTbFe layer deposited on a specially prepared silicon wafer disk, provided with Si/sub 3/N/sub 4/ windows. This allows direct observation by Lorentz microscopy of the magnetization patterns dynamically written under recording conditions. It is shown that by locally heating the GdTbFe layer with a continuous laser beam, combined with high-frequency switching of the magnetic field, very high storage densities can be achieved. Domains with a length of 0.25 ..mu..m in the direction of disk rotation could be written.
Lorentz microscopy on dynamically written domains in GdTbFe
Greidanus, F. J. A. M.; Jacobs, B. A. J.; den Broeder, F. J. A.; Spruit, J. H. M.; Rosenkranz, M.
1989-03-01
In this letter a new method for the observation of thermomagnetically written domains using Lorentz electron microscopy is discussed. Domains are written in a GdTbFe layer deposited on a specially prepared silicon wafer disk, provided with Si3N4 windows. This allows direct observation by Lorentz microscopy of the magnetization patterns dynamically written under recording conditions. It is shown that by locally heating the GdTbFe layer with a continuous laser beam, combined with high-frequency switching of the magnetic field, very high storage densities can be achieved. Domains with a length of 0.25 μm in the direction of disk rotation could be written.
Direct Lorentz force compensation flowmeter for electrolytes
Energy Technology Data Exchange (ETDEWEB)
Vasilyan, S., E-mail: suren.vasilyan@tu-ilmenau.de; Froehlich, Th. [Institute of Process Measurement and Sensor Technology, Ilmenau University of Technology, 98684 Ilmenau (Germany)
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.
The electrodeless Lorentz force thruster experiment
Weber, Thomas E.
The Electrodeless Lorentz Force (ELF) thruster is a novel type of plasma thruster, which utilizes Rotating Magnetic Field current drive within a diverging magnetic field to form, accelerate, and eject a Field Reversed Configuration plasmoid. The ELF program is a result of a Small Business Technology Transfer grant awarded to MSNW LLC by the Air Force Office of Scientific Research for the research of the revolutionary space propulsion concept represented by ELF. These grants are awarded to small businesses working in collaboration with a university, in this case, the University of Washington. The program was split into two concurrent research efforts; a numerical modeling study undertaken at the UW branch of the Plasma Science and Innovation Center, and an experimental effort taking place at the UW Plasma Dynamics Laboratory with additional support from MSNW (the latter being the subject of this dissertation). It is the aim of this dissertation is to present to the reader the necessary background information needed to understand the operation of the ELF thruster, an overview of the experimental setup, a review of the significant experimental findings, and a discussion regarding the operation and performance of the thruster.
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 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.
Entropy production due to Lorentz invariance violation
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.
ICECUBE NEUTRINOS AND LORENTZ INVARIANCE VIOLATION
Energy Technology Data Exchange (ETDEWEB)
Amelino-Camelia, Giovanni [Dipartimento di Fisica, Sapienza Università di Roma and INFN, Sez. Roma1, P.le A. Moro 2, I-00185 Roma (Italy); Guetta, D. [Osservatorio astronomico di Roma, v. Frascati 33, I-00040 Monte Porzio Catone (Italy); Piran, Tsvi [The Racah Institute for Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel)
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.
Dynamical 3-Space: neo-Lorentz Relativity
Cahill, Reginald T
2012-01-01
The major extant relativity theories - Galileo's Relativity (GaR), Lorentz's Relativity (LR) and Einstein's Special Relativity (SR), with the latter much celebrated, while the LR is essentially ignored. Indeed it is often incorrectly claimed that SR and LR are experimentally indistinguishable. Here we show that (i) SR and LR are experimentally distinguishable, (ii) that comparison of gas-mode Michelson interferometer experiments with spacecraft earth-flyby Doppler shift data demonstrate that it is LR that is consistent with the data, while SR is in conflict with the data, (iii) SR is exactly derivable from GaR by means of a mere linear change of space and time coordinates that mixes the Galilean space and time coordinates. So it is GaR and SR that are equivalent. Hence the well-known SR relativistic effects are purely coordinate effects, and cannot correspond to the observed relativistic effects. The connections between these three relativity theories has become apparent following the discovery that space is ...
Geometrical Lorentz Violation and Quantum Mechanical Physics
Mignani, R; Cardone, F
2013-01-01
On the basis of the results of some experiments dealing with the violation of Local Lorentz Invariance (LLI) and on the formalism of the Deformed Special Relativity (DSR), we examine the connections between the local geometrical structure of space-time and the foundation of Quantum Mechanics. We show that Quantum Mechanics, beside being an axiomatic theory, can be considered also a deductive physical theory, deducted from the primary physical principle of Relativistic Correlation. This principle is synonym of LLI and of a rigid and at minkowskian space-time. The results of the experiments mentioned above show the breakdown of LLI and hence the violation of the principle of Relativistic Correlation. The formalism of DSR allows to highlight the deep meaning of LLI breakdown in terms of the geometrical structure of local space-time which, far from being rigid and at, is deformed by the energy of the physical phenomena that take place and in this sense it has an active part in the dynamics of the whole physical p...
Aspects of Black Holes in Gravitational Theories with Broken Lorentz and Diffeomorphism Symmetries
Satheeshkumar, V H
2015-01-01
Since Stephen Hawking discovered that black holes emit thermal radiation, black holes have become the theoretical laboratories for testing our ideas on quantum gravity. This dissertation is devoted to the study of singularities, the formation of black holes by gravitational collapse and the global structure of spacetime. All our investigations are in the context of a recently proposed approach to quantum gravity, which breaks Lorentz and diffeomorphism symmetries at very high energies.
Lorentz violation effects in asymmetric two brane models a nonperturbative analysis
Farakos, K
2009-01-01
We consider the case of bulk photons in a Lorentz violating brane background, with an asymmetric warping between space and time warp factors. A perturbative analysis, in a previous work, gave an energy dependent phase (or group) velocity of light: $V_{ph}(\\omega)=V_{ph}(0)-C_G \\:\\omega^2 \\quad (C_G>0)$, which was derived up to second order of time independent perturbation theory. In this paper, we go beyond the perturbative result and we study the nonperturbative behavior of the phase velocity for larger energies, by solving numerically an eigenvalue problem for the wave function of the zero mode (4D photon). In particular we see that $V_{ph}(\\omega)$ is in general a monotonically decreasing function which tends asymptotically to a final value $V_{ph}(\\infty)$. We compare with the results of perturbation theory and we obtain a very good agreement in the range of small energies. We also present a wave function analysis and we see that in the nonperturbative sector of the theory (very high energies), the zero m...
Lorentz, the Solvay Councils and the Physics Institute
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
Recording experiments on rare-earth transition-metal thin films studied with Lorentz microscopy
Energy Technology Data Exchange (ETDEWEB)
Greidanus, F.J.A.M.; Jacobs, B.A.J.; Spruit, J.H.M. (Philips Research Labs., Eindhoven (Netherlands)); Klahn, S. (Philips GmbH Forschungslaboratorium Hamburg, D-2000 Hamburg (DE))
1989-09-01
Domains written thermomagnetically under recording conditions in rare-earth transition-metal thin films are studied with Lorentz microscopy. New technique in which the magneto-optical layer is deposited on specially prepared silicon wafer disks, provided with Si/sub 3/N/sub 4/ windows is described. This technique allows direct observation of the written domain patterns in the electron microscope. It is demonstrated that the nucleation process plays a crucial role when writing in TbFeCo. Different compositions, having different temperature dependencies of the magnetic properties, lead to remarkably different domain-formation behaviour. With the detailed insight into the shape and structure of domains obtained by Lorentz microscopy, carrier and noise levels obtained from recording experiments can be understood. This is demonstrated with data on GdTbFe. It is shown that magnetic-field modulation, apart from the advantage of direct overwrite, offers the possibility of very high density recording.
A New Limit on Planck Scale Lorentz Violation from Gamma-ray Burst Polarization
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.
A Real Lorentz-FitzGerald Contraction
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.
High quality factor indium oxide mechanical microresonators
Energy Technology Data Exchange (ETDEWEB)
Bartolomé, Javier, E-mail: j.bartolome@fis.ucm.es; Cremades, Ana; Piqueras, Javier [Department of Materials Physics, Faculty of Physics, Universidad Complutense de Madrid, 28040 Madrid (Spain)
2015-11-09
The mechanical resonance behavior of as-grown In{sub 2}O{sub 3} microrods has been studied in this work by in-situ scanning electron microscopy (SEM) electrically induced mechanical oscillations. Indium oxide microrods grown by a vapor–solid method are naturally clamped to an aluminum oxide ceramic substrate, showing a high quality factor due to reduced energy losses during mechanical vibrations. Quality factors of more than 10{sup 5} and minimum detectable forces of the order of 10{sup −16} N/Hz{sup 1/2} demonstrate their potential as mechanical microresonators for real applications. Measurements at low-vacuum using the SEM environmental operation mode were performed to study the effect of extrinsic damping on the resonators behavior. The damping coefficient has been determined as a function of pressure.
An implicit δf particle-in-cell method with sub-cycling and orbit averaging for Lorentz ions
Sturdevant, Benjamin J.; Parker, Scott E.; Chen, Yang; Hause, Benjamin B.
2016-07-01
A second order implicit δf Lorentz ion hybrid model with sub-cycling and orbit averaging has been developed to study low-frequency, quasi-neutral plasmas. Models using the full Lorentz force equations of motion for ions may be useful for verifying gyrokinetic ion simulation models in applications where higher order terms may be important. In the presence of a strong external magnetic field, previous Lorentz ion models are limited to simulating very short time scales due to the small time step required for resolving the ion gyromotion. Here, we use a simplified model for ion Landau damped ion acoustic waves in a uniform magnetic field as a test bed for developing efficient time stepping methods to be used with the Lorentz ion hybrid model. A detailed linear analysis of the model is derived to validate simulations and to examine the significance of ion Bernstein waves in the Lorentz ion model. Linear analysis of a gyrokinetic ion model is also performed, and excellent agreement with the dispersion results from the Lorentz ion model is demonstrated for the ion acoustic wave. The sub-cycling/orbit averaging algorithm is shown to produce accurate finite-Larmor-radius effects using large macro-time steps sizes, and numerical damping of high frequency fluctuations can be achieved by formulating the field model in terms of the perturbed flux density. Furthermore, a CPU-GPU implementation of the sub-cycling/orbit averaging is presented and is shown to achieve a significant speedup over an equivalent serial code.
Lorentz Violation of the Photon Sector in Field Theory Models
Directory of Open Access Journals (Sweden)
Lingli Zhou
2014-01-01
Full Text Available We compare the Lorentz violation terms of the pure photon sector between two field theory models, namely, the minimal standard model extension (SME and the standard model supplement (SMS. From the requirement of the identity of the intersection for the two models, we find that the free photon sector of the SMS can be a subset of the photon sector of the minimal SME. We not only obtain some relations between the SME parameters but also get some constraints on the SMS parameters from the SME parameters. The CPT-odd coefficients (kAFα of the SME are predicted to be zero. There are 15 degrees of freedom in the Lorentz violation matrix Δαβ of free photons of the SMS related with the same number of degrees of freedom in the tensor coefficients (kFαβμν, which are independent from each other in the minimal SME but are interrelated in the intersection of the SMS and the minimal SME. With the related degrees of freedom, we obtain the conservative constraints (2σ on the elements of the photon Lorentz violation matrix. The detailed structure of the photon Lorentz violation matrix suggests some applications to the Lorentz violation experiments for photons.
A theoretical model for the Lorentz force particle analyzer
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
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.
Indian Academy of Sciences (India)
Arghya Nandi; Sumanta Neogy; Sankha Bhaduri
2011-02-01
This work presents performance analysis of a Lorentz force based noncontact vibration exciter by mounting a couple of permanent magnets on a piezoelectric stack. A conductor is attached to the structure to be excited and is placed midway between unlike poles of a couple of permanent magnets. The permanent magnets are placed on a piezoelectric stack. This stack, because of its nano-positioning capabilities, can impart an accurate and adjustable harmonic vibratory motion to the couple of permanent magnets. The piezoelectric stack, because of its high stiffness remains uncoupled with the dynamics of the structure. Due to the relative motion between the magnets and the conductor, Lorentz force is generated within the conductor. This Lorentz force is responsible for vibration of the structure in a plane parallel to the pole faces of the magnets. This keeps the magnetic field almost independent of the vibration of the structure and the chance of the structure hitting the magnet during large vibration is totally eliminated. If the amplitude of displacement of the stack is kept constant, the non-contact excitation force in this exciter remains proportional to the excitation frequency. Though use of this exciter eliminates mass (apart from that of the conductor attached to the structure) and stiffness coupling, a known damping term gets added to that of the excited structure.
Iterative reconstruction of magnetic induction using Lorentz transmission electron tomography
Energy Technology Data Exchange (ETDEWEB)
Phatak, C., E-mail: cd@anl.gov [Materials Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Gürsoy, D. [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States)
2015-03-15
Intense ongoing research on complex nanomagnetic structures requires a fundamental understanding of the 3D magnetization and the stray fields around the nano-objects. 3D visualization of such fields offers the best way to achieve this. Lorentz transmission electron microscopy provides a suitable combination of high resolution and ability to quantitatively visualize the magnetization vectors using phase retrieval methods. In this paper, we present a formalism to represent the magnetic phase shift of electrons as a Radon transform of the magnetic induction of the sample. Using this formalism, we then present the application of common tomographic methods particularly the iterative methods, to reconstruct the 3D components of the vector field. We present an analysis of the effect of missing wedge and the limited angular sampling as well as reconstruction of complex 3D magnetization in a nanowire using simulations. - Highlights: • We present a formalism to represent electron-optical magnetic phase shift as a Radon transform of the 3D magnetic induction of the nano-object. • We have analyzed four different tomographic reconstruction methods for vectorial data reconstruction. • Reconstruction methods were tested for varying experimental limitations such as limited tilt range and limited angular sampling. • The analysis showed that Gridrec and SIRT methods performed better with lower errors than other reconstruction methods.
Abramowski, A; Aharonian, F; Akhperjanian, A G; Anton, G; Barnacka, A; de Almeida, U Barres; 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; Bulik, T; Büsching, I; Bühler, R; 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; Frster, A; Fontaine, G; Füßling, M; 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; 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; Wilhelmi, E de Oña; Opitz, B; Ostrowski, M; Panter, M; Arribas, M Paz; Pedaletti1, 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; Reyes, R de los; 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; 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
2011-01-01
Several models of Quantum Gravity predict Lorentz Symmetry breaking at energy scales approaching the Planck scale (10^{19} 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, a more sensitive event-by-event method consisting of a likelihood fit is applied to PKS 2155-304 flare data of MJD 52944 (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 M^{l}_{QG} > 2.1x10^{18} GeV and is currently the best result obtained with blazars. The sensitivity to the quadratic term ...
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.
On the origin of neutrino oscillations through Lorentz violation
Leite, Julio
2015-07-01
The possibility of generating neutrino masses and oscillations through Lorentz- violating models is investigated. In the first model, an interaction between a fermion doublet and a Lorentz-violating gauge field, which play the role of a regulator field and, eventually, decouples from the fermions, is considered. In this case, by solving the (non-perturbative) Schwinger-Dyson equation, we show how masses and oscillations are generated dynamically. In the second model, fermions with LV kinematics interact via a four-fermion interaction and masses are shown to be generated dynamically when using another non-perturbative method. In both models, the recovery of Lorentz invariance is discussed and it is shown that the only physical observables are the dynamical masses that lead to neutrino oscillations.
Spontaneous breaking of Lorentz symmetry for canonical gravity
Gielen, Steffen
2012-01-01
In the Ashtekar-Barbero formulation of canonical general relativity based on an SU(2) connection, Lorentz covariance is a subtle issue which has been the focus of some debate. Here we present a Lorentz covariant formulation generalising the notion of a foliation of spacetime to a field of local observers which specify a time direction only locally. This field spontaneously breaks the local SO(3,1) symmetry down to a subgroup SO(3); we show that the apparent symmetry breaking to SO(3) is not in conflict with Lorentz covariance. We give a geometric picture of our construction as Cartan geometrodynamics and outline further applications of the formalism of local observers, motivating the idea that observer space, instead of spacetime, should serve as the fundamental arena for gravitational physics.
Spontaneous Breaking of Lorentz Symmetry with an antisymmetric tensor
Hernaski, Carlos A
2016-01-01
Spontaneous violation of Lorentz symmetry by the vacuum condensation of an antisymmetric $2$-tensor is considered. 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 non-invariant scenarios. Besides the two photon polarizations, just one Goldstone mode must be dynamical to set a sensible low-energy effective model, and the enhancement of the stability by accounting interaction terms points to a protection against observational Lorentz violation.
Dynamical ambiguities in models with spontaneous Lorentz violation
Bonder, Yuri
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.
Lorentz symmetry breaking as a quantum field theory regulator
Visser, Matt
2009-01-01
Perturbative expansions of relativistic quantum field theories typically contain ultraviolet divergences requiring regularization and renormalization. Many different regularization techniques have been developed over the years, but most regularizations require severe mutilation of the logical foundations of the theory. In contrast, breaking Lorentz invariance, while it is certainly a radical step, at least does not damage the logical foundations of the theory. We shall explore the features of a Lorentz symmetry breaking regulator in a simple polynomial scalar field theory, and discuss its implications. We shall quantify just "how much" Lorentz symmetry breaking is required to fully regulate the theory and render it finite. This scalar field theory provides a simple way of understanding many of the key features of Horava's recent article [arXiv:0901.3775 [hep-th
Testing Lorentz Symmetry with the Double Chooz Eexperiment
Katori, Teppei
2013-01-01
The Double Chooz reactor-based oscillation experiment searches for an electron antineutrino disappearance signal to investigate the neutrino mass matrix mixing angle theta 13. Double Chooz's reported evidence for this disappearance is generally interpreted as mass-driven mixing through this parameter. However, the electron antineutrino candidates collected by the experiment can also be used to search for a signature of the violation of Lorentz invariance. We study the sidereal time dependence of the antineutrino signal rate and probe Lorentz violation within the Standard-Model Extension (SME) framework. We find that the data prefer the sidereal time independent solution, and a number of limits are applied to the relevant SME coefficients, including the first constraints on those associated with Lorentz violation in the e-tau mixing sector.
Spacetime Variation of Lorentz-Violation Coefficients at Nonrelativistic Scale
Lane, Charles D
2016-01-01
The notion of uniform and/or constant tensor fields of rank $>0$ is incompatible with general curved spacetimes. This work considers the consequences of certain tensor-valued coefficients for Lorentz violation in the Standard-Model Extension varying with spacetime position. We focus on two of the coefficients, $a_\\mu$ and $b_\\mu$, that characterize Lorentz violation in massive fermions, particularly in those fermions that constitute ordinary matter. We calculate the nonrelativistic hamiltonian describing these effects, and use it to extract the sensitivity of several precision experiments to coefficient variation.
Search for Lorentz Violation in km$^3$-Scale Neutrino Telescopes
Argüelles, C A; Conrad, J M; Katori, T; Kheirandish, A
2016-01-01
Kilometer$^3$-scale neutrino detectors such as IceCube, ANTARES, and the proposed Km3Net neutrino observatory in the Mediterranean have measured, and will continue to characterize, the atmospheric neutrino spectrum above 1 TeV. Such precise measurements enable us to probe new neutrino physics, in particular, those that arise from Lorentz violation. In this paper, we first relate the effective new physics hamiltonian terms with the Lorentz violating literature. Second, we calculate the oscillation probability formulas for the two-level $\
Lorentz and CPT violation in the Standard-Model Extension
Lehnert, Ralf
2016-01-01
Lorentz and CPT invariance are among the symmetries that can be investigated with ultrahigh precision in subatomic physics. Being spacetime symmetries, Lorentz and CPT invariance can be violated by minuscule amounts in many theoretical approaches to underlying physics that involve novel spacetime concepts, such as quantized versions of gravity. Regardless of the underlying mechanism, the low-energy effects of such violations are expected to be governed by effective field theory. This talk provides a survey of this idea and includes an overview of experimental efforts in the field.
How is Lorentz invariance encoded in the Hamiltonian?
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.
How is Lorentz Invariance encoded in the Hamiltonian?
Kajuri, Nirmalya
2016-01-01
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.
Limits on violations of Lorentz Symmetry from Gravity Probe B
Bailey, Quentin G; Overduin, James M
2013-01-01
Generic violations of Lorentz symmetry 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). We obtain new constraints on the gravitational sector of the SME using recently published final results from Gravity Probe B. These include for the first time an upper limit at the 10^(-3) level on the time-time component of the new tensor field responsible for inducing local Lorentz violation in the theory, and an independent limit at the 10^(-7) level on a combination of components of this tensor field.
Four-dimensional aether-like Lorentz-breaking QED revisited and problem of ambiguities
Energy Technology Data Exchange (ETDEWEB)
Baeta Scarpelli, A.P. [Setor Tecnico-Cientifico, Departamento de Policia Federal, Rua Hugo D' Antola, 95, Lapa, Sao Paulo (Brazil); Mariz, T. [Universidade Federal de Alagoas, Instituto de Fisica, Maceio, Alagoas (Brazil); Nascimento, J.R.; Petrov, A.Yu. [Universidade Federal da Paraiba, Departamento de Fisica, Caixa Postal 5008, Joao Pessoa, Paraiba (Brazil)
2013-08-15
In this paper, we consider the perturbative generation of the CPT-even aether-like Lorentz-breaking term in the extended Lorentz-breaking QED within different approaches and discuss its ambiguities. (orig.)
Signals for Lorentz and CPT Violation in Atomic Spectroscopy Experiments and Other Systems
Vargas, Arnaldo J
2016-01-01
The prospects of studying nonminimal operators for Lorentz violation using spectroscopy experiments with light atoms and muon spin-precession experiments are presented. Possible improvements on bounds on minimal and nonminimal operators for Lorentz violation are discussed.
Direct measurement of Lorentz transformation with Doppler effects
Chen, Shao-Guang
, r is the unit vector from lamphouse point to counters. Or: L (0) L (pi) =L0 (1+(v/c)) L0 (1 - (v/c)) =L0 2 y2 =L2 Or: L ≡ [L(0)L(pi)]1/2 =L0 y , which y ≡ (1 - (v/c)2 )1/2 is just Fitzgerald-Lorentzian contraction-factor. Also, when a light-wave period p is defined as time unit, from Doppler's frequency-shift the count N with p of one period T of moving-clock is: T(q) = N(q) p = T0 /(1+(v/c) cos q) Or: T ≡ (T(0) T(pi))1/2 = T 0 /y , where T0 is the proper period when v = 0, which is just the moving-clock-slower effect. Let r from clock point to lamp-house ((v/c) symbol reverse), Doppler formula in the usual form is: f (q) = 1/T(q) = f0 (1 - (v/c) cos q). Therefore, Lorentz transformation is the square root average of positive and negative directions twice metrical results of Doppler's frequency-shift, which Doppler's once items ( positive and negative v/c ) are counteract only residual twice item (v/c)2 (relativity-factor). Then Lorentz transformation can be directly measured by Doppler's frequency-shift method. The half-life of moving mu-meson is statistical average of many particles, the usual explanation using relativity-factor y is correct. An airship moving simultaneously along contrary directions is impossible, which makes that the relativity-factor y and the twin-paradox are inexistent in the macroscopical movement. Thereby, in the navigations of airship or satellite only use the measurement of Doppler's frequency-shift but have no use for Lorentz transformation.
Test of Lorentz invariance in $\\beta$ decay of polarized $^{20}\\text{Na}$
Sytema, A; Böll, O; Chernowitz, D; Dijck, E A; Grasdijk, J O; Hoekstra, S; Jungmann, K; Mathavan, S C; Meinema, C; Mohanty, A; Müller, S E; Noordmans, J P; Portela, M Nuñez; Onderwater, C J G; Pijpker, C; Timmermans, R G E; Vos, K K; Willmann, L; Wilschut, H W
2016-01-01
We search for a dependence of the lifetime of $^{20}\\text{Na}$ nuclei on the nuclear spin direction. Such a directional dependence would be evidence for Lorentz-invariance violation in weak interactions. A difference in lifetime between nuclei that are polarized in the east and west direction is searched for. This difference is maximally sensitive to the rotation of the Earth, while the sidereal dependence is free from most systematic errors. The experiment sets a limit of $2\\times 10^{-4}$ at 90 % C.L. on the amplitude of the sidereal variation of the relative lifetime differences, an improvement by a factor 15 compared to an earlier result.
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).
BPS Maxwell-Chern-Simons-like vortices in a Lorentz-violating framework
Casana, R; Da Hora, E; Neves, A B F
2013-01-01
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.
BPS Maxwell-Chern Vortices in a Lorentz-Violating Framework
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.
Lorentz covariant field theory on noncommutative spacetime based on DFR algebra
Okumura, Y
2003-01-01
Lorentz covariance is the fundamental principle of every relativistic field theory which insures consistent physical descriptions. Even if the space-time is noncommutative, field theories on it should keep Lorentz covariance. In this letter, it is shown that the field theory on noncommutative spacetime is Lorentz covariant if the noncommutativity emerges from the algebra of spacetime operators described by Doplicher, Fredenhagen and Roberts.
Lorentz space estimates for the Coulombian renormalized energy
Serfaty, Sylvia
2011-01-01
In this paper we obtain optimal estimates for the "currents" associated to point masses in the plane, in terms of the Coulombian renormalized energy of Sandier-Serfaty \\cite{ss1,ss3}. To derive the estimates, we use a technique that we introduced in \\cite{st}, which couples the "ball construction method" to estimates in the Lorentz space $L^{2,\\infty}$.
Prospects for Lorentz and CPT tests with hydrogen and antihydrogen
Becker, Tobias Frederic
2017-01-01
As a summer student for 13 weeks in the ASACUSA-CUSP collaboration, under the supervision of Chloé Malbrunot, my project consisted in a first part on the theoretical treatment of Lorentz and CPT violation in hydrogen & antihydrogen in the framework of the Standard Model Extension SME and in second part on experimental measurements on a hydrogen beam.
The scientific correspondence of H. A. Lorentz: Volume I
Kox, A.J.
2008-01-01
This book presents a selection of 434 carefully annotated letters from and to the Dutch physicist and Nobel Prize winner Hendrik Antoon Lorentz (1853-1928), covering the period from 1883 until a few months before his death in February 1928. Most of these letters are of a scientific nature, with the
Lorentz invariance and the semiclassical approximation of loop quantum gravity
Energy Technology Data Exchange (ETDEWEB)
Kozameh, Carlos N; Parisi, Florencia [Facultad de Matematica, AstronomIa y FIsica, Universidad Nacional de Cordoba, Ciudad Universitaria (5000) Cordoba (Argentina)
2004-06-07
It is shown that the field equations derived from an effective interaction Hamiltonian for Maxwell and gravitational fields in the semiclassical approximation of loop quantum gravity using rotational invariant states (such as weave states) are Lorentz invariant. To derive this result, which is in agreement with the observational evidence, we use the geometrical properties of the electromagnetic field.
Time correlation functions for the one-dimensional Lorentz gas
Mazo, R.M.; Beijeren, H. van
1983-01-01
The velocity autocorrelation function and related quantities are investigated for the one-dimensional deterministic Lorentz gas, consisting of randomly distributed fixed scatterers and light particles moving back and forth between two of these at a constant given speed. An expansion for the velocity
The generators of Lorentz transformation in momentum space
Institute of Scientific and Technical Information of China (English)
张鹏飞; 阮图南
2002-01-01
In the momentum space, the angular momentum operator and the boost vector operator,i.e. the generators for the Lorentz transformation of a particle with arbitrary spin and nonzero mass are discussed. Some new expressions are obtained in terms of the orbital and spin parts.``
Spontaneous Lorentz violation: the case of infrared QED
Energy Technology Data Exchange (ETDEWEB)
Balachandran, A. P., E-mail: bal@phy.syr.edu [Physics Department, Syracuse University, 13244-1130, Syracuse, NY (United States); Kürkçüoǧlu, S., E-mail: kseckin@metu.edu.tr [Department of Physics, Middle East Technical University, 06800, Ankara (Turkey); Queiroz, A. R. de, E-mail: amilcarq@unb.br [Instituto de Física, Universidade de Brasília, Caixa Postal 04455, 70919-970, Brasília, DF (Brazil); Departamento de Física Teórica, Facultad de Ciencias, Universidad de Zaragoza, 50009, Zaragoza (Spain); Vaidya, S., E-mail: vaidya@cts.iisc.ernet.in [Centre for High Energy Physics, Indian Institute of Science, 560012, Bangalore (India)
2015-02-24
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 U(1) 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.
Spontaneous Lorentz violation: the case of infrared QED
Energy Technology Data Exchange (ETDEWEB)
Balachandran, A.P. [Syracuse University, Physics Department, Syracuse, NY (United States); Kuerkcueoglu, S. [Middle East Technical University, Department of Physics, Ankara (Turkey); Queiroz, A.R. de [Universidade de Brasilia, Instituto de Fisica, Brasilia (Brazil); Universidad de Zaragoza, Departamento de Fisica Teorica, Facultad de Ciencias, Zaragoza (Spain); Vaidya, S. [Indian Institute of Science, Centre for High Energy Physics, Bangalore (India)
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 U(1) 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. (orig.)
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.
Limits on Lorentz violation in neutral-Kaon decay
Vos, K.K.; Wilschut, H. W.; Timmermans, R. G. E.
2013-01-01
The KLOE collaboration recently reported bounds on the directional dependence of the lifetime of the short-lived neutral kaon K_S with respect to the cosmic microwave background dipole anisotropy. We interpret their results in a general framework developed to probe Lorentz violation in the weak
Lorentz- and CPT-symmetry studies in subatomic physics
Energy Technology Data Exchange (ETDEWEB)
Lehnert, Ralf, E-mail: ralehner@indiana.edu [Leibniz Universität Hannover (Germany)
2016-12-15
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.
Acoustic Tests of Lorentz Symmetry Using Quartz Oscillators
Directory of Open Access Journals (Sweden)
Anthony Lo
2016-02-01
Full Text Available We propose and demonstrate a test of Lorentz symmetry based on new, compact, and reliable quartz oscillator technology. Violations of Lorentz invariance in the matter and photon sector of the standard model extension generate anisotropies in particles’ inertial masses and the elastic constants of solids, giving rise to measurable anisotropies in the resonance frequencies of acoustic modes in solids. A first realization of such a “phonon-sector” test of Lorentz symmetry using room-temperature stress-compensated-cut crystals yields 120 h of data at a frequency resolution of 2.4×10^{−15} and a limit of c[over ˜]_{Q}^{n}=(−1.8±2.2×10^{−14} GeV on the most weakly constrained neutron-sector c coefficient of the standard model extension. Future experiments with cryogenic oscillators promise significant improvements in accuracy, opening up the potential for improved limits on Lorentz violation in the neutron, proton, electron, and photon sector.
Limits on Lorentz Violation from Forbidden beta Decays
Noordmans, J.P.; Wilschut, H.W.; Timmermans, R.G.E.
2013-01-01
Forbidden (slow) beta 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
Lorentz-violating effects in three-dimensional QED
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.
On the Lorentz degree of a product of polynomials
Ait-Haddou, Rachid
2015-01-01
In this note, we negatively answer two questions of T. Erdélyi (1991, 2010) on possible lower bounds on the Lorentz degree of product of two polynomials. We show that the correctness of one question for degree two polynomials is a direct consequence of a result of Barnard et al. (1991) on polynomials with nonnegative coefficients.
Path Integrals and Lorentz Violation in Polymer Quantized Scalar Fields
Kajuri, Nirmalya
2014-01-01
We obtain a path integral formulation of polymer quantized scalar field theory, starting from the Hilbert Space framework. This brings the polymer quantized scalar field theory under the ambit of Feynman diagrammatic techniques. The path integral formulation also shows that Lorentz invariance is lost for the Klein-Gordon field.
Special Relativity in Week One: 3) Introducing the Lorentz Contraction
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…
Generalization of the Lorentz-Dirac equation to include spin
Barut, A. O.; Unal, Nuri
1989-11-01
For the classical point electron with Zitterbewegung (hence spin) we derive, after regularization, the radiation reaction force and covariant equations for the dynamical variables (xμ, πμ, vμ, and Sμν), which reduce to the Lorentz-Dirac equation in the spinless limit.
Special Relativity in Week One: 3) Introducing the Lorentz Contraction
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…
On the conformal geometry of transverse Riemann Lorentz manifolds
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.
Intrinsic Geometry of Curves and the Lorentz Equation
Caltenco, J. H.; Linares, R. M. Y.; López-Bonilla, J. L.
2002-07-01
We show that the trajectory of a point charge in a uniform electromagnetic field is a helix if the Lorentz equation governs its motion. Our approach is totally relativistic, and it is based on the use of the Frenet-Serret formulae which describe the intrinsic geometry of world lines in Minkowski spacetime.
Spacetime Variation of Lorentz-Violation Coefficients at Nonrelativistic Scale
Lane, Charles D
2016-01-01
When the Standard-Model Extension (SME) is applied in curved spacetime, the Lorentz-violation coefficients must depend on spacetime position. This work describes some of the consequences of this spacetime variation. We focus on effects that appear at a nonrelativistic scale and extract sensitivity of completed experiments to derivatives of SME coefficient fields.
The scientific correspondence of H. A. Lorentz: Volume I
Kox, A.J.
2008-01-01
This book presents a selection of 434 carefully annotated letters from and to the Dutch physicist and Nobel Prize winner Hendrik Antoon Lorentz (1853-1928), covering the period from 1883 until a few months before his death in February 1928. Most of these letters are of a scientific nature, with the
Lorentz force sigmometry: A contactless method for electrical conductivity measurements
Uhlig, Robert P.; Zec, Mladen; Ziolkowski, Marek; Brauer, Hartmut; Thess, André
2012-05-01
The present communication reports a new technique for the contactless measurement of the specific electrical conductivity of a solid body or an electrically conducting fluid. We term the technique "Lorentz force sigmometry" where the neologism "sigmometry" is derived from the Greek letter sigma, often used to denote the electrical conductivity. Lorentz force sigmometry (LoFoS) is based on similar principles as the traditional eddy current testing but allows a larger penetration depth and is less sensitive to variations in the distance between the sensor and the sample. We formulate the theory of LoFoS and compute the calibration function which is necessary for determining the unknown electrical conductivity from measurements of the Lorentz force. We conduct a series of experiments which demonstrate that the measured Lorentz forces are in excellent agreement with the numerical predictions. Applying this technique to an aluminum sample with a known electrical conductivity of σAl=20.4MS/m and to a copper sample with σCu=57.92MS/m we obtain σAl=21.59MS/m and σCu=60.08MS/m, respectively. This demonstrates that LoFoS is a convenient and accurate technique that may find application in process control and thermo-physical property measurements for solid and liquid conductors.
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.
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)
Gamma-ray burst polarization reduction induced by the Lorentz invariance violation
Lin, Hai-Nan; Chang, Zhe
2016-01-01
It has been observed that photons in the prompt emission of some gamma-ray bursts (GRBs) are highly polarized. The high polarization is used by some authors to give a strict constraint on the Lorentz invariance violation (LIV). If the Lorentz invariance is broken, the polarization vector of a photon may rotate during its propagation. The rotation angle of polarization vector depends on both the photon energy and the distance of source. It is believed that if high polarization is observed, then the relative rotation angle (denoted by $\\alpha$) of polarization vector of the highest energy photon with respect to that of the lowest energy photon should be no more than $\\pi/2$. Otherwise, the net polarization will be severely suppressed, thus couldn't be as high as what was actually observed. In this paper, we will give a detailed calculation on the evolution of GRB polarization arising from LIV effect duration the propagation. It is shown that the polarization degree rapidly decrease as $\\alpha$ increases, and re...
Abe, K.; Amey, J.; Andreopoulos, C.; Antonova, M.; Aoki, S.; Ariga, A.; Assylbekov, S.; Autiero, D.; Ban, S.; Barbato, F. C. T.; Barbi, M.; Barker, G. J.; Barr, G.; Barry, C.; Bartet-Friburg, P.; Batkiewicz, M.; Berardi, V.; Berkman, S.; Bhadra, S.; Bienstock, S.; Blondel, A.; Bolognesi, S.; Bordoni, S.; Boyd, S. B.; Brailsford, D.; Bravar, A.; Bronner, C.; Buizza Avanzini, M.; Calland, R. G.; Campbell, T.; Cao, S.; Cartwright, S. L.; Castillo, R.; Catanesi, M. G.; Cervera, A.; Chappell, A.; Checchia, C.; Cherdack, D.; Chikuma, N.; Christodoulou, G.; Clifton, A.; Coleman, J.; Collazuol, G.; Coplowe, D.; Cremonesi, L.; Cudd, A.; Dabrowska, A.; De Rosa, G.; Dealtry, T.; Denner, P. F.; Dennis, S. R.; Densham, C.; Dewhurst, D.; Di Lodovico, F.; Di Luise, S.; Dolan, S.; Drapier, O.; Duffy, K. E.; Dumarchez, J.; Dunkman, M.; Dziewiecki, M.; Emery-Schrenk, S.; Ereditato, A.; Feusels, T.; Finch, A. J.; Fiorentini, G. A.; Friend, M.; Fujii, Y.; Fukuda, D.; Fukuda, Y.; Furmanski, A. P.; Galymov, V.; Garcia, A.; Giffin, S. G.; Giganti, C.; Gizzarelli, F.; Golan, T.; Gonin, M.; Grant, N.; Hadley, D. R.; Haegel, L.; Haigh, J. T.; Hamilton, P.; Hansen, D.; Harada, J.; Hara, T.; Hartz, M.; Hasegawa, T.; Hastings, N. C.; Hayashino, T.; Hayato, Y.; Helmer, R. L.; Hierholzer, M.; Hillairet, A.; Himmel, A.; Hiraki, T.; Hiramoto, A.; Hirota, S.; Hogan, M.; Holeczek, J.; Hosomi, F.; Huang, K.; Ichikawa, A. K.; Ieki, K.; Ikeda, M.; Imber, J.; Insler, J.; Intonti, R. A.; Irvine, T. J.; Ishida, T.; Ishii, T.; Iwai, E.; Iwamoto, K.; Izmaylov, A.; Jacob, A.; Jamieson, B.; Jiang, M.; Johnson, S.; Jo, J. H.; Jonsson, P.; Jung, C. K.; Kabirnezhad, M.; Kaboth, A. C.; Kajita, T.; Kakuno, H.; Kameda, J.; Karlen, D.; Karpikov, I.; Katori, T.; Kearns, E.; Khabibullin, M.; Khotjantsev, A.; Kielczewska, D.; Kikawa, T.; Kim, H.; Kim, J.; King, S.; Kisiel, J.; Knight, A.; Knox, A.; Kobayashi, T.; Koch, L.; Koga, T.; Konaka, A.; Kondo, K.; Kopylov, A.; Kormos, L. L.; Korzenev, A.; Koshio, Y.; Kowalik, K.; Kropp, W.; Kudenko, Y.; Kurjata, R.; Kutter, T.; Lagoda, J.; Lamont, I.; Lamoureux, M.; Larkin, E.; Lasorak, P.; Laveder, M.; Lawe, M.; Lazos, M.; Licciardi, M.; Lindner, T.; Liptak, Z. J.; Litchfield, R. P.; Li, X.; Longhin, A.; Lopez, J. P.; Lou, T.; Ludovici, L.; Lu, X.; Magaletti, L.; Mahn, K.; Malek, M.; Manly, S.; Maret, L.; Marino, A. D.; Marteau, J.; Martin, J. F.; Martins, P.; Martynenko, S.; Maruyama, T.; Matveev, V.; Mavrokoridis, K.; Ma, W. Y.; Mazzucato, E.; McCarthy, M.; McCauley, N.; McFarland, K. S.; McGrew, C.; Mefodiev, A.; Metelko, C.; Mezzetto, M.; Mijakowski, P.; Minamino, A.; Mineev, O.; Mine, S.; Missert, A.; Miura, M.; Moriyama, S.; Morrison, J.; Mueller, Th. A.; Murphy, S.; Myslik, J.; Nakadaira, T.; Nakahata, M.; Nakamura, K. G.; Nakamura, K.; Nakamura, K. D.; Nakanishi, Y.; Nakayama, S.; Nakaya, T.; Nakayoshi, K.; Nantais, C.; Nielsen, C.; Nirkko, M.; Nishikawa, K.; Nishimura, Y.; Novella, P.; Nowak, J.; O'Keeffe, H. M.; Ohta, R.; Okumura, K.; Okusawa, T.; Oryszczak, W.; Oser, S. M.; Ovsyannikova, T.; Owen, R. A.; Oyama, Y.; Palladino, V.; Palomino, J. L.; Paolone, V.; Patel, N. D.; Paudyal, P.; Pavin, M.; Payne, D.; Perkin, J. D.; Petrov, Y.; Pickard, L.; Pickering, L.; Pinzon Guerra, E. S.; Pistillo, C.; Popov, B.; Posiadala-Zezula, M.; Poutissou, J.-M.; Poutissou, R.; Przewlocki, P.; Quilain, B.; Radermacher, T.; Radicioni, E.; Ratoff, P. N.; Ravonel, M.; Rayner, M. A.; Redij, A.; Reinherz-Aronis, E.; Riccio, C.; Rojas, P.; Rondio, E.; Rossi, B.; Roth, S.; Rubbia, A.; Ruggeri, A. C.; Rychter, A.; Sacco, R.; Sakashita, K.; Sánchez, F.; Sato, F.; Scantamburlo, E.; Scholberg, K.; Schwehr, J.; Scott, M.; Seiya, Y.; Sekiguchi, T.; Sekiya, H.; Sgalaberna, D.; Shah, R.; Shaikhiev, A.; Shaker, F.; Shaw, D.; Shiozawa, M.; Shirahige, T.; Short, S.; Smy, M.; Sobczyk, J. T.; Sobel, H.; Sorel, M.; Southwell, L.; Stamoulis, P.; Steinmann, J.; Stewart, T.; Stowell, P.; Suda, Y.; Suvorov, S.; Suzuki, A.; Suzuki, K.; Suzuki, S. Y.; Suzuki, Y.; Tacik, R.; Tada, M.; Takahashi, S.; Takeda, A.; Takeuchi, Y.; Tamura, R.; Tanaka, H. K.; Tanaka, H. A.; Terhorst, D.; Terri, R.; Thakore, T.; Thompson, L. F.; Tobayama, S.; Toki, W.; Tomura, T.; Touramanis, C.; Tsukamoto, T.; Tzanov, M.; Uchida, Y.; Vacheret, A.; Vagins, M.; Vallari, Z.; Vasseur, G.; Vilela, C.; Vladisavljevic, T.; Wachala, T.; Wakamatsu, K.; Walter, C. W.; Wark, D.; Warzycha, W.; Wascko, M. O.; Weber, A.; Wendell, R.; Wilkes, R. J.; Wilking, M. J.; Wilkinson, C.; Wilson, J. R.; Wilson, R. J.; Wret, C.; Yamada, Y.; Yamamoto, K.; Yamamoto, M.; Yanagisawa, C.; Yano, T.; Yen, S.; Yershov, N.; Yokoyama, M.; Yoo, J.; Yoshida, K.; Yuan, T.; Yu, M.; Zalewska, A.; Zalipska, J.; Zambelli, L.; Zaremba, K.; Ziembicki, M.; Zimmerman, E. D.; Zito, M.; Żmuda, J.; T2K Collaboration
2017-06-01
A class of extensions of the Standard Model allows Lorentz and C P T violations, which can be identified by the observation of sidereal modulations in the neutrino interaction rate. A search for such modulations was performed using the T2K on-axis near detector. Two complementary methods were used in this study, both of which resulted in no evidence of a signal. Limits on associated Lorentz and C P T -violating terms from the Standard Model extension have been derived by taking into account their correlations in this model for the first time. These results imply such symmetry violations are suppressed by a factor of more than 1 020 at the GeV scale.
Energy Technology Data Exchange (ETDEWEB)
Bhattacharyya, Sampriti; Pilipenko, Roman; /Fermilab
2010-01-01
Superconducting accelerators, such as the International Linear Collider (ILC), rely on very high Q accelerating cavities to achieve high electric fields at low RF power. Such cavities have very narrow resonances: a few kHz with a 1.3GHz resonance frequency for the ILC. Several mechanical factors cause tune shifts much larger than this: pressure variations in the liquid helium bath; microphonics from pumps and other mechanical devices; and for a pulsed machine such as the ILC, Lorentz force detuning (pressure from the contained RF field). Simple passive stiffening is limited by many manufacturing and material considerations. Therefore, active tuning using piezo actuators is needed. Here we study a supply for their operation. Since commercial power amplifiers are expensive, we analyzed the characteristics of four power amplifiers: (iPZD) built by Istituto Nazionale di Fisica Nucleare (Sezione di Pisa); and a DC-DC converter power supply built in Fermilab (Piezo Master); and two commercial amplifiers, Piezosystem jena and Piezomechanik. This paper presents an analysis and characterization of these amplifiers to understand the cost benefit and reliability when using in a large scale, pulsed beam accelerator like the ILC.
Performance enhancement of a Lorentz force velocimeter using a buoyancy-compensated magnet system
Ebert, R.; Leineweber, J.; Resagk, C.
2015-07-01
Lorentz force velocimetry (LFV) is a highly feasible method for measuring flow rate in a pipe or a duct. This method has been established for liquid metal flows but also for electrolytes such as saltwater. A decrease in electrical conductivity of the medium causes a decrease of the Lorentz force which needs to be resolved, affecting the accuracy of the measurement. We use an electrical force compensation (EFC) balance for the determination of the tiny force signals in a test channel filled with electrolyte solution. It is used in a 90°-rotated orientation with a magnet system hanging vertically on its load bar. The thin coupling elements of its parallel guiding system limit the mass of the magnets to 1 kg. To overcome this restriction, which limits the magnetic flux density and hence the Lorentz forces, a weight force compensation mechanism is developed. Therefore, different methods such as air bearing are conceivable, but for the elimination of additional horizontal force components which would disturb the force signal, only compensation by lift force provided by buoyancy is reasonable. We present a swimming body setup that will allow larger magnet systems than before, because a large amount of the weight force will be compensated by this lift force. Thus the implementation of this concept has to be made with respect to hydrodynamical and mechanical stability. This is necessary to avoid overturning of the swimming body setup and to prevent inelastic deformation. Additionally, the issue will be presented and discussed whether thermal convection around the lifting body diminishes the signal-to-noise ratio (SNR) significantly or not.
Influences of Lorentz force on the hydrofoil lift
Institute of Scientific and Technical Information of China (English)
Yaohui Chen; Baochun Fan; Zhihua Chen; Hongzhi Li
2009-01-01
In this paper, Lorentz forces are proved to be able to suppress separation in flows over hydrofoils. Further-more, a differential equation of pressure distributions on the hydrofoil surface is derived, from which it is found that BVF (boundary vortex flux) cr is a suitable criterion for describing the lift coefficient variations during the electromagnetic control process. According to our numerical results, the peri-odic variations of lift for a hydrofoil at an attack angle of 17 o are analyzed and its inherent mechanism is discussed in detail with the concept of BVE On the other hand, the effects of Lorentz force on the hydrofoil's lift are investigated both experimentally and numerically for different magnitudes and locations.
Earth's Inner Core dynamics induced by the Lorentz force
Lasbleis, M; Cardin, P; Labrosse, S
2015-01-01
Seismic studies indicate that the Earth's inner core has a complex structure and exhibits a strong elastic anisotropy with a cylindrical symmetry. Among the various models which have been proposed to explain this anisotropy, one class of models considers the effect of the Lorentz force associated with the magnetic field diffused within the inner core. In this paper we extend previous studies and use analytical calculations and numerical simulations to predict the geometry and strength of the flow induced by the poloidal component of the Lorentz force in a neutrally or stably stratified growing inner core, exploring also the effect of different types of boundary conditions at the inner core boundary (ICB). Unlike previous studies, we show that the boundary condition that is most likely to produce a significant deformation and seismic anisotropy is impermeable, with negligible radial flow through the boundary. Exact analytical solutions are found in the case of a negligible effect of buoyancy forces in the inne...
Manipulating the Lorentz force via the chirality of nanoparticles
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.
Testing Lorentz invariance of dark matter with satellite galaxies
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.
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).
Teleparallel equivalent of general relativity and local Lorentz transformation: Revisited
Nashed, Gamal G L
2016-01-01
It is well known that the field equations of teleparallel theory which is equivalent to general relativity (TEGR) completely agree with the field equation of general relativity (GR). However, TEGR has six extra degrees of freedom which spoil the true physics. These extra degrees are related to the local Lorentz transformation. In this study, we give three different tetrads of flat horizon space-time that depend only on the radial coordinate. One of these tetrads contains an arbitrary function which comes from local Lorentz transformation. We show by explicate calculations that this arbitrary function spoils the calculations of the conserved charges. We formulate {\\it a skew-symmetric tensor} whose vanishing value put a constraint on the arbitrary function. This constraint makes the conserved charges are free from the arbitrary function.
Noncommutativity in (2+1)-dimensions and the Lorentz group
Falomir, H; Gamboa, J; Méndez, F; Loewe, M
2012-01-01
In this article we considered models of particles living in a three-dimensional space-time with a nonstandard noncommutativity induced by shifting canonical coordinates and momenta with generators of a unitary irreducible representation of the Lorentz group. The Hilbert space gets the structure of a direct product with the representation space, where we are able to construct operators which realize the algebra of Lorentz transformations. We study the modified Landau problem for both Schr\\"odinger and Dirac particles, whose Hamiltonians are obtained through a kind of non-Abelian Bopp's shift of the dynamical variables from the ones of the usual problem in the normal space. The spectrum of these models are considered in perturbation theory, both for small and large noncommutativity parameters. We find no constraint between the parameters referring to no-commutativity in coordinates and momenta but they rather play similar roles. Since the representation space of the unitary irreducible representations SL(2,R) c...
Convolution of Lorentz Invariant Ultradistributions and Field Theory
Bollini, C G
2003-01-01
In this work, a general definition of convolution between two arbitrary four dimensional Lorentz invariant (fdLi) Tempered Ultradistributions is given, in both: Minkowskian and Euclidean Space (Spherically symmetric tempered ultradistributions). The product of two arbitrary fdLi distributions of exponential type is defined via the convolution of its corresponding Fourier Transforms. Several examples of convolution of two fdLi Tempered Ultradistributions are given. In particular we calculate exactly the convolution of two Feynman's massless propagators. An expression for the Fourier Transform of a Lorentz invariant Tempered Ultradistribution in terms of modified Bessel distributions is obtained in this work (Generalization of Bochner's formula to Minkowskian space). At the same time, and in a previous step used for the deduction of the convolution formula, we obtain the generalization to the Minkowskian space, of the dimensional regularization of the perturbation theory of Green Functions in the Euclidean conf...
Inertial frames without the relativity principle: breaking Lorentz symmetry
Baccetti, Valentina; Visser, Matt
2013-01-01
We investigate inertial frames in the absence of Lorentz invariance, reconsidering the usual group structure implied by the relativity principle. We abandon the relativity principle, discarding the group structure for the transformations between inertial frames, while requiring these transformations to be at least linear (to preserve homogeneity). In theories with a preferred frame (aether), the set of transformations between inertial frames forms a groupoid/pseudogroup instead of a group, a characteristic essential to evading the von Ignatowsky theorems. In order to understand the dynamics, we also demonstrate that the transformation rules for energy and momentum are in general affine. We finally focus on one specific and compelling model implementing a minimalist violation of Lorentz invariance.
Lorentz Angle Measurement for CO2/Isobutane Gas Mixtures
Hoshina, K; Khalatyan, N S; Nitoh, O; Okuno, H; Kato, Y; Kobayashi, M; Kurihara, Y; Kuroiwa, H; Nakamura, Y; Sakieda, K; Suzuki, Y; Watanabe, T
2002-01-01
We have developed a Lorentz angle measurement system for cool gas mixtures in the course of our R&D for a proposed JLC central drift chamber (JLC-CDC). The measurement system is characterized by the use of two laser beams to produce primary electrons and flash ADCs to read their signals simultaneously. With this new system, we have measured Lorentz angles for CO2/isobutane gas mixtures with different proportions (95:5, 90:10, and 85:15), varying drift field from 0.6 to 2.0 kV/cm and magnetic field up to 1.5 T. The results of the measurement are in good agreement with GARFIELD/MAGBOLTZ simulations.
Non Linear Lorentz Transformation and Doubly Special Relativity
Atehortua, A N; Mira, J M; Vanegas, N
2012-01-01
We generate non-linear representations of the Lorentz Group by unitary transformation over the Lorentz generators. To do that we use deformed scale transformations by introducing momentum-depending parameters. The momentum operator transformation is found to be equivalent to a particle momentum transformation. The configuration space transformation is found to depend on the old momentum operator and we show that this transformation generates models with two scales, one for the velocity ($c$) and another one for the energy. A Lagrangian formalism is proposed for these models and an effective metric for the deformed Minkowski space is found. We show that the Smolin model is one in a family of doubly special relativity. Finally we construct an ansatz for the quantization of such theories.
On multipliers of Fourier series in the Lorentz space
Ydyrys, Aizhan Zh.; Tleukhanova, Nazerke T.
2016-08-01
We study the multipliers of Fourier series on the Lorentz spaces, in particular, the sufficient conditions for a sequence of complex numbers {λk}k∈Z in order to make it a multiplier of trigonometric Fourier series of space Lp,r [0; 1] in the Lq,r [0; 1]. In the paper there is a new multipliers theorem which is supplement of the well-known theorems, and given a counterexample.
Modified gravity and binary pulsars: the Lorentz violating case
Blas, Diego
2016-01-01
The dynamics of binary pulsars can be used to test different aspects of gravitation. This is particularly important to constrain alternatives to general relativity in regimes which are not probed by other methods. In this short contribution, I will describe the case of theories of gravity without Lorentz invariance. The latter are important in the context of quantum gravity and modify the laws of gravity at basically all scales.
Direct observation of rectified motion of vortices by Lorentz microscopy
Indian Academy of Sciences (India)
Yoshihiko Togawa; Ken Harada; Tetsuya Akashi; Hiroto Kasai; Tsuyoshi Matsuda; Atsutaka maeda; Akira Tonomura
2006-01-01
We have investigated the vortex dynamics for the `ratchet' operation in a niobium superconductor via a direct imaging of Lorentz microscopy. We directly observe one-directional selective motion of field-gradient-driven vortices along fabricated channels. This results from the rectification of vortices in a spatially asymmetric potential under the oscillating magnetic field in a temporally symmetric manner. Based on the observation of the individual motion of vortices, we clarify the elementary process involved in this rectification.
Black hole entropy and Lorentz-diffeomorphism Noether charge
Jacobson, Ted; Mohd, Arif
2015-01-01
We show that, in the first or second order orthonormal frame formalism, black hole entropy is the horizon Noether charge for a combination of diffeomorphism and local Lorentz symmetry involving the Lie derivative of the frame. The Noether charge for diffeomorphisms alone is unsuitable, since a regular frame cannot be invariant under the flow of the Killing field at the bifurcation surface. We apply this formalism to Lagrangians polynomial in wedge products of the frame field 1-form and curvat...
A Michelson-Morley Test of Lorentz Symmetry for Electrons
Pruttivarasin, T; Porsev, S G; Tupitsyn, I I; Safronova, M; Hohensee, M A; Haeffner, H
2014-01-01
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 physics by requiring all particles and fields to be invariant under Lorentz transformations. The most well-known test of this important cornerstone of physics are Michelson-Morley-type experiments\\cite{MM, Herrmann2009,Eisele2009} verifying the isotropy of the speed of light. Lorentz symmetry also implies that the kinetic energy of an electron should be independent of the direction of its velocity, \\textit{i.e.,} its dispersion relation should be isotropic in space. In this work, we search for violation of Lorentz symmetry for electrons by performing an electronic analogue of a Michelson-Morley experiment. We split an electron-wavepacket bound inside a calcium ion into two parts with different orientations and recombine them after a time evolution of 95~ms. As the Earth rotates, the absolute spatial orientation of the wavepackets changes and anisotropies in ...
Remote sub-wavelength focusing of ultrasonically activated Lorentz current
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.
Directory of Open Access Journals (Sweden)
Hui Zhang
2017-01-01
Full Text Available The control of vortex-induced vibration (VIV in shear flow with different distributions of Lorentz force is numerically investigated based on the stream function–vorticity equations in the exponential-polar coordinates exerted on moving cylinder for Re = 150. The cylinder motion equation coupled with the fluid, including the mathematical expressions of the lift force coefficient C l , is derived. The initial and boundary conditions as well as the hydrodynamic forces on the surface of cylinder are also formulated. The Lorentz force applied to suppress the VIV has no relationship with the flow field, and involves two categories, i.e., the field Lorentz force and the wall Lorentz force. With the application of symmetrical Lorentz forces, the symmetric field Lorentz force can amplify the drag, suppress the flow separation, decrease the lift fluctuation, and then suppress the VIV while the wall Lorentz force decreases the drag only. With the application of asymmetrical Lorentz forces, besides the above-mentioned effects, the field Lorentz force can increase additional lift induced by shear flow, whereas the wall Lorentz force can counteract the additional lift, which is dominated on the total effect.
Demographic Factors Affecting Internet Using Purposes of High School Students
Kilic, Abdullah Faruk; Güzeller, Cem Oktay
2017-01-01
This study aimed at determining the impact of demographic factors on the Internet usage purposes of high school students. The population of the study consisted of students between 9th and 12th grades from the Anatolian high schools, science high schools, social sciences high schools, sports high schools and fine arts high schools in Turkey. The…
QCD factorization for forward hadron scattering at high energies
Ermolaev, B I; Troyan, S I
2011-01-01
We consider the QCD factorization of DIS structure functions at small x and amplitudes of 2->2 -hadronic forward scattering at high energy. We show that both collinear and k_T-factorization for these processes can be obtained approximately as reductions of a more general (totally unintegrated) form of the factorization. The requirement of ultraviolet and infrared stability of the factorization convolutions allows us to obtain restrictions on the fits for the parton distributions in k_T- and collinear factorization.
Status and prospects for CPT and Lorentz invariance violation searches in neutral meson mixing
Directory of Open Access Journals (Sweden)
Jeroen van Tilburg
2015-03-01
Full Text Available An overview of current experimental bounds on CPT violation in neutral meson mixing is given. New values for the CPT asymmetry in the B0 and Bs0 systems are deduced from published BaBar, Belle and LHCb results. With dedicated analyses, LHCb will be able to further improve the bounds on CPT violation in the D0, B0 and Bs0 systems. Since CPT violation implies violation of Lorentz invariance in an interacting local quantum field theory, the observed CPT asymmetry will exhibit sidereal- and boost-dependent variations. Such CPT-violating and Lorentz-violating effects are accommodated in the framework of the Standard Model Extension (SME. The large boost of the neutral mesons produced at LHCb results in a high sensitivity to the corresponding SME coefficients. For the B0 and Bs0 systems, using existing LHCb results, we determine with high precision the SME coefficients that are not varying with sidereal time. With a full sidereal analysis, LHCb will be able to improve the existing SME bounds in the D0, B0 and Bs0 systems by up to two orders of magnitude.
Constaints on Lorentz symmetry violations using lunar laser ranging observations
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
Yu, Peicheng; Decyk, Viktor K; An, Weiming; Vieira, Jorge; Tsung, Frank S; Fonseca, Ricardo A; Lu, Wei; Silva, Luis O; Mori, Warren B
2013-01-01
Simulating laser wakefield acceleration (LWFA) in a Lorentz boosted frame in which the plasma drifts towards the laser with $v_b$ can speedup the simulation by factors of $\\gamma^2_b=(1-v^2_b/c^2)^{-1}$. In these simulations the relativistic drifting plasma inevitably induces a high frequency numerical instability that contaminates the interested physics. Various approaches have been proposed to mitigate this instability. One approach is to solve Maxwell equations in Fourier space (a spectral solver) as this has been shown to suppress the fastest growing modes of this instability in simple test problems using a simple low pass, ring (in two dimensions), or shell (in three dimensions) filter in Fourier space. We describe the development of a fully parallelized, multi-dimensional, particle-in-cell code that uses a spectral solver to solve Maxwell's equations and that includes the ability to launch a laser using a moving antenna. This new EM-PIC code is called UPIC-EMMA and it is based on the components of the U...
Stanwix, P L; Wolf, P; Susli, M; Locke, C R; Ivanov, E N; Winterflood, J; Van Kann, F; Stanwix, Paul L.; Tobar, Michael E.; Wolf, Peter; Susli, Mohamad; Locke, Clayton R.; Ivanov, Eugene N.; Winterflood, John; Kann, Frank van
2005-01-01
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 frame-work 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_{e-}^{ZZ} component of 2.1(5.7)x10^{-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 -2.6(2.1)x10^{-10} on the isotropy parameter, P_{MM}= delta - beta + 1/2 is set, which is a factor of 7 improvement.
Discussion on Lorentz invariance violation of noncommutative field theory and neutrino oscillation
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.
Kumar, Abhay
2013-01-01
The small bandwidth of superconducting cavities makes the study of dynamic Lorentz force detuning and its compensation indispensable in case of pulsed mode operation of high gradient accelerators. In this paper, we present the study of this detuning and also propose an optimized design for five cell 650 MHz {\\beta}g= 0.9 elliptic superconducting cavities, which will be used in the high energy section of the 1 GeV H-LINAC for the proposed Indian Spallation Neutron Source project, by suitably inserting the inter-cell stiffeners. The paper presents a sequential design methodology which starts with study of static Lorentz force detuning and tunability; and progresses to find out the structural modes and related dynamic detuning values by performing transient calculations. The developed methodology is general in nature and can be used for a three dimensional model of any geometry. The work will be useful for optimizing the design against dynamic Lorentz force detuning of SRF cavities of any shape.
Wang, Shen; Huang, Songling; Zhang, Yu; Zhao, Wei
2016-12-01
The electromagnetic acoustic transducers (EMATs) are gaining much attention in recent years due to their non-contact operation in ultrasonic wave generation and reception in NDT field. Quite often the transduction efficiency of EMATs is low, so efforts are always necessary to gain a better understanding of their complex and multi-physics transduction mechanism. In this work, we focused on modeling of an omni-directional Lorentz force-based EMAT operating on an aluminum disk and containing a rounded meander coil to generate a pure Lamb wave mode. We introduced an approach to solve the underlying eddy current equations in cylindrical coordinates directly, and applied this approach to a multi-conductor electromagnetic model to investigate the skin and proximity effects. These effects existed both for the complete and incomplete equations. Then we built the omni-directional EMAT model composed of three sub-models and two geometries. The two-geometry structure made it possible to reduce the total number of elements. Time varying spatial distribution of the Lorentz force vector was plotted. Propagation velocity of the simulated wave packet was compared with the group velocity of desired S0 mode Lamb waves. Interaction of the waves with a slot defect with a depth of 50% thickness was studied. The response to high current excitation and dynamic magnetic field was also investigated.
Design and simulation of superconducting Lorentz Force Electrical Impedance Tomography (LFEIT)
Energy Technology Data Exchange (ETDEWEB)
Shen, Boyang, E-mail: bs506@cam.ac.uk; Fu, Lin, E-mail: lf359@cam.ac.uk; Geng, Jianzhao, E-mail: jg717@cam.ac.uk; Zhang, Xiuchang, E-mail: xz326@cam.ac.uk; Zhang, Heng, E-mail: hz301@cam.ac.uk; Dong, Qihuan, E-mail: qd210@cam.ac.uk; Li, Chao, E-mail: cl644@cam.ac.uk; Li, Jing, E-mail: jl908@cam.ac.uk; Coombs, T.A., E-mail: tac1000@cam.ac.uk
2016-05-15
Highlights: • Design of superconducting magnets using Halbach Array configuration. • Combination of superconducting magnets together with Lorentz Force Electrical Impedance Tomography (LFEIT) system. • Simulation of superconducting LFEIT system based on the theory of magneto-acoustic effect. - Abstract: Lorentz Force Electrical Impedance Tomography (LFEIT) is a hybrid diagnostic scanner with strong capability for biological imaging, particularly in cancer and haemorrhages detection. This paper presents the design and simulation of a novel combination: a superconducting magnet together with LFEIT system. Superconducting magnets can generate magnetic field with high intensity and homogeneity, which could significantly enhance the imaging performance. The modelling of superconducting magnets was carried out using Finite Element Method (FEM) package, COMSOL Multiphysics, which was based on Partial Differential Equation (PDE) model with H-formulation coupling B-dependent critical current density and bulk approximation. The mathematical model for LFEIT system was built based on the theory of magneto-acoustic effect. The magnetic field properties from magnet design were imported into the LFEIT model. The basic imaging of electrical signal was developed using MATLAB codes. The LFEIT model simulated two samples located in three different magnetic fields with varying magnetic strength and homogeneity.
Quasi Maximum Likelihood Analysis of High Dimensional Constrained Factor Models
Li, Kunpeng; Li,Qi; Lu, Lina
2016-01-01
Factor models have been widely used in practice. However, an undesirable feature of a high dimensional factor model is that the model has too many parameters. An effective way to address this issue, proposed in a seminar work by Tsai and Tsay (2010), is to decompose the loadings matrix by a high-dimensional known matrix multiplying with a low-dimensional unknown matrix, which Tsai and Tsay (2010) name constrained factor models. This paper investigates the estimation and inferential theory ...
Reality conditions for Ashtekar gravity from Lorentz-covariant formulation
Energy Technology Data Exchange (ETDEWEB)
Alexandrov, Sergei [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, Postbus 80.195, 3508 TD Utrecht (Netherlands)
2006-03-21
We study the limit of the Lorentz-covariant canonical formulation where the Immirzi parameter approaches {beta} = i. We show that, formulated in terms of a shifted spacetime connection, which also plays a crucial role in the covariant quantization, the limit is smooth and reproduces the canonical structure of the self-dual Ashtekar gravity. The reality conditions of Ashtekar gravity can be incorporated by means of the Dirac brackets derived from the covariant formulation and defined on an extended phase space which involves, besides the self-dual variables, also their anti-self-dual counterparts.
Lorentz symmetry violation, dark matter and dark energy
Gonzalez-Mestres, Luis
2009-01-01
Taking into account the experimental results of the HiRes and AUGER collaborations, the present status of bounds on Lorentz symmetry violation (LSV) patterns is discussed. Although significant constraints will emerge, a wide range of models and values of parameters will still be left open. Cosmological implications of allowed LSV patterns are discussed focusing on the origin of our Universe, the cosmological constant, dark matter and dark energy. Superbradyons (superluminal preons) may be the actual constituents of vacuum and of standard particles, and form equally a cosmological sea leading to new forms of dark matter and dark energy.
Wigner–Souriau translations and Lorentz symmetry of chiral fermions
Directory of Open Access Journals (Sweden)
C. Duval
2015-03-01
Full Text Available Chiral fermions can be embedded into Souriau's massless spinning particle model by “enslaving” the spin, viewed as a gauge constraint. The latter is not invariant under Lorentz boosts; spin enslavement can be restored, however, by a Wigner–Souriau (WS translation, analogous to a compensating gauge transformation. The combined transformation is precisely the recently uncovered twisted boost, which we now extend to finite transformations. WS-translations are identified with the stability group of a motion acting on the right on the Poincaré group, whereas the natural Poincaré action corresponds to action on the left.
Quantum-Gravity Induced Lorentz Violation and Dynamical Mass Generation
Mavromatos, Nick E.
2010-01-01
In Ref. [1] (by J. Alexandre) a minimal extension of (3+1)-dimensional Quantum Electrodynamics has been proposed, which includes Lorentz-Violation (LV) in the form of higher-(spatial)-derivative isotropic terms in the gauge sector, suppressed by a mass scale $M$. The model can lead to dynamical mass generation for charged fermions. In this article I elaborate further on this idea and I attempt to connect it to specific quantum-gravity models, inspired from string/brane theory. Specifically, i...
Getting the Lorentz transformations without requiring an invariant speed
Pelissetto, A
2015-01-01
The structure of the Lorentz transformations follows purely from the absence of privileged inertial reference frames and the group structure (closure under composition) of the transformations---two assumptions that are simple and physically necessary. The existence of an invariant speed is \\textit{not} a necessary assumption, and in fact is a consequence of the principle of relativity (though the finite value of this speed must, of course, be obtained from experiment). Von Ignatowsky derived this result in 1911, but it is still not widely known and is absent from most textbooks. Here we present a completely elementary proof of the result, suitable for use in an introductory course in special relativity.
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.
Photon emission and decay from generic Lorentz invariance violation
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.
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.
Gravitation as a Plastic Distortion of the Lorentz Vacuum
Fernández, Virginia Velma
2010-01-01
Addressing graduate students and researchers in theoretical physics and mathematics, this book presents a new formulation of the theory of gravity. In the new approach the gravitational field has the same ontology as the electromagnetic, strong, and weak fields. In other words it is a physical field living in Minkowski spacetime. Some necessary new mathematical concepts are introduced and carefully explained. Then they are used to describe the deformation of geometries, the key to describing the gravitational field as a plastic deformation of the Lorentz vacuum. It emerges after further analysis that the theory provides trustworthy energy-momentum and angular momentum conservation laws, a feature that is normally lacking in General Relativity.
Lorentz-Dirac force from QED for linear acceleration
Higuchi, Atsushi; Martin, Giles D.
2004-10-01
We investigate the motion of a wave packet of a charged scalar particle linearly accelerated by a static potential in quantum electrodynamics. We calculate the expectation value of the position of the charged particle after the acceleration to first order in the fine structure constant in the ℏ→0 limit. We find that the change in the expectation value of the position (the position shift) due to radiation reaction agrees exactly with the result obtained using the Lorentz-Dirac force in classical electrodynamics. We also point out that the one-loop correction to the potential may contribute to the position change in this limit.
Black hole entropy and Lorentz-diffeomorphism Noether charge
Jacobson, Ted
2015-01-01
We show that, in the first or second order orthonormal frame formalism, black hole entropy is the horizon Noether charge for a combination of diffeomorphism and local Lorentz symmetry involving the Lie derivative of the frame. The Noether charge for diffeomorphisms alone is unsuitable, since a regular frame cannot be invariant under the flow of the Killing field at the bifurcation surface. We apply this formalism to Lagrangians polynomial in wedge products of the frame field 1-form and curvature 2-form, including general relativity, Lovelock gravity, and "topological" terms in four dimensions.
Unifying Ghost-Free Lorentz-Invariant Lagrangians
Li, Wenliang
2015-01-01
We present the details of the novel framework for Lagrangian field theories that are Lorentz-invariant and lead to at most second order equations of motion. The use of antisymmetric structure is of crucial importance. The general ghost-free Lagrangians are constructed and then translated into the language of differential forms. The ghost-freeness has a geometric nature. A novel duality is proposed which generalizes the Hodge duality in Maxwell's theory. We discuss how the well-established theories are reformulated and propose many new theories.
Lorentz-invariant formulation of Cherenkov radiation by tachyons
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.
Lorentz and CPT violation in the hydrogen spectrum
Adkins, Gregory S
2013-01-01
We have studied the effect of hypothetical violations of Lorentz and CPT symmetry by calculating the corrections to the energy levels of hydrogen induced by the Standard-Model Extension (SME). Hydrogen studies are interesting because the energy levels of hydrogen can be measured with great precision and the theory for hydrogen based on the Standard Model (SM) is well understood. We obtained corrections through order \\alpha^2 times the SME parameters for all levels of hydrogen and applied them to determine the SME corrections to the transition frequency for the 2S-1S transition.
Wigner-Souriau translations and Lorentz symmetry of chiral fermions
Duval, C; Horvathy, P A; Zhang, P -M
2014-01-01
Chiral fermions can be embedded into Souriau's massless spinning particle model by "enslaving" the spin, viewed as a gauge constraint. The latter is not invariant under Lorentz boosts; spin enslavement can be restored, however, by a subsequent Wigner-Souriau (WS) translation, analogous to a compensating gauge transformation. The combined transformation is precisely the recently uncovered twisted boost, which we now extend to finite transformations. WS-translations are identified with the stability group of a motion acting on the right on the Poincare group, whereas the natural Poincare action corresponds to action on the left.
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.
New Horizons in Multidimensional Diffusion: The Lorentz Gas and the Riemann Hypothesis
Dettmann, Carl P.
2012-01-01
The Lorentz gas is a billiard model involving a point particle diffusing deterministically in a periodic array of convex scatterers. In the two dimensional finite horizon case, in which all trajectories involve collisions with the scatterers, displacements scaled by the usual diffusive factor sqrt{t} are normally distributed, as shown by Bunimovich and Sinai in 1981. In the infinite horizon case, motion is superdiffusive, however the normal distribution is recovered when scaling by sqrt {tln t}, with an explicit formula for its variance. Here we explore the infinite horizon case in arbitrary dimensions, giving explicit formulas for the mean square displacement, arguing that it differs from the variance of the limiting distribution, making connections with the Riemann Hypothesis in the small scatterer limit, and providing evidence for a critical dimension d=6 beyond which correlation decay exhibits fractional powers. The results are conditional on a number of conjectures, and are corroborated by numerical simulations in up to ten dimensions.
Extremely High Q-factor metamaterials due to Anapole Excitation
Basharin, Alexey A; Volsky, Nikita; Kafesaki, Maria; Economou, Eleftherios N
2016-01-01
We demonstrate that ideal anapole metamaterials have infinite Q-factor. We have designed and fabricated a metamaterial consisting of planar metamolecules which exhibit anapole behavior in the sense that the electric dipole radiation is almost cancelled by the toroidal dipole one, producing thus an extremely high Q-factor at the resonance frequency. The size of the system, at the mm range, and the parasitic magnetic quadrupole radiation are the factors limiting the size of the Q-factor. In spite of the very low radiation losses the local fields at the metamolecules are extremely high, of the order of higher than the external incoming field.
QCD factorization for forward hadron scattering at high energies
Energy Technology Data Exchange (ETDEWEB)
Ermolaev, B.I. [Ioffe Physico-Technical Institute, St. Petersburg (Russian Federation); Greco, M. [University Roma Tre, Department of Physics, Rome (Italy); INFN, Rome (Italy); Troyan, S.I. [St. Petersburg Institute of Nuclear Physics, Gatchina (Russian Federation)
2012-03-15
We consider the QCD factorization of DIS structure functions at small x and amplitudes of 2{yields}2 hadronic forward scattering at high energy. We show that both collinear and k{sub T} -factorization for these processes can be obtained approximately as reductions of a more general (totally unintegrated) form of the factorization. The requirement of ultraviolet and infrared stability of the factorization convolutions allows us to obtain restrictions on the fits for the parton distributions in k{sub T} - and collinear factorization. (orig.)
Optical Characterization of Lorentz Force Based CMOS-MEMS Magnetic Field Sensor
Directory of Open Access Journals (Sweden)
John Ojur Dennis
2015-07-01
Full Text Available Magnetic field sensors are becoming an essential part of everyday life due to the improvements in their sensitivities and resolutions, while at the same time they have become compact, smaller in size and economical. In the work presented herein a Lorentz force based CMOS-MEMS magnetic field sensor is designed, fabricated and optically characterized. The sensor is fabricated by using CMOS thin layers and dry post micromachining is used to release the device structure and finally the sensor chip is packaged in DIP. The sensor consists of a shuttle which is designed to resonate in the lateral direction (first mode of resonance. In the presence of an external magnetic field, the Lorentz force actuates the shuttle in the lateral direction and the amplitude of resonance is measured using an optical method. The differential change in the amplitude of the resonating shuttle shows the strength of the external magnetic field. The resonance frequency of the shuttle is determined to be 8164 Hz experimentally and from the resonance curve, the quality factor and damping ratio are obtained. In an open environment, the quality factor and damping ratio are found to be 51.34 and 0.00973 respectively. The sensitivity of the sensor is determined in static mode to be 0.034 µm/mT when a current of 10 mA passes through the shuttle, while it is found to be higher at resonance with a value of 1.35 µm/mT at 8 mA current. Finally, the resolution of the sensor is found to be 370.37 µT.
Optical Characterization of Lorentz Force Based CMOS-MEMS Magnetic Field Sensor.
Dennis, John Ojur; Ahmad, Farooq; Khir, M Haris Bin Md; Bin Hamid, Nor Hisham
2015-07-27
Magnetic field sensors are becoming an essential part of everyday life due to the improvements in their sensitivities and resolutions, while at the same time they have become compact, smaller in size and economical. In the work presented herein a Lorentz force based CMOS-MEMS magnetic field sensor is designed, fabricated and optically characterized. The sensor is fabricated by using CMOS thin layers and dry post micromachining is used to release the device structure and finally the sensor chip is packaged in DIP. The sensor consists of a shuttle which is designed to resonate in the lateral direction (first mode of resonance). In the presence of an external magnetic field, the Lorentz force actuates the shuttle in the lateral direction and the amplitude of resonance is measured using an optical method. The differential change in the amplitude of the resonating shuttle shows the strength of the external magnetic field. The resonance frequency of the shuttle is determined to be 8164 Hz experimentally and from the resonance curve, the quality factor and damping ratio are obtained. In an open environment, the quality factor and damping ratio are found to be 51.34 and 0.00973 respectively. The sensitivity of the sensor is determined in static mode to be 0.034 µm/mT when a current of 10 mA passes through the shuttle, while it is found to be higher at resonance with a value of 1.35 µm/mT at 8 mA current. Finally, the resolution of the sensor is found to be 370.37 µT.
Projected Constraints on Lorentz-Violating Gravity with Gravitational Waves
Hansen, Devin; Yagi, Kent
2014-01-01
Gravitational waves are excellent tools to probe the foundations of General Relativity in the strongly dynamical and non-linear 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. We here study whether waves emitted in the late, quasi-circular inspiral of non-spinning, neutron star binaries can place competitive constraints on two proxies of gravitational Lorentz-violation: Einstein-\\AE{}ther 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/weak-gravity approximation. We assume a gravitational wave consistent wi...
Cosmic censorship in Lorentz-violating theories of gravity
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.
A test of local Lorentz invariance with Compton scattering asymmetry
Mohanmurthy, P; Dutta, D
2016-01-01
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 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 $c_{TY}$. 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 Lorentz invarianc...
Consistency analysis of a nonbirefringent Lorentz-violating planar model
Energy Technology Data Exchange (ETDEWEB)
Casana, Rodolfo; Ferreira, Manoel M.; Moreira, Roemir P.M. [Universidade Federal do Maranhao (UFMA), Departamento de Fisica, Sao Luis, MA (Brazil)
2012-07-15
In this work analyze the physical consistency of a nonbirefringent Lorentz-violating planar model via the analysis of the pole structure of its Feynman propagators. The nonbirefringent planar model, obtained from the dimensional reduction of the CPT-even gauge sector of the standard model extension, is composed of a gauge and a scalar fields, being affected by Lorentz-violating (LIV) coefficients encoded in the symmetric tensor {kappa}{sub {mu}{nu}}. The propagator of the gauge field is explicitly evaluated and expressed in terms of linear independent symmetric tensors, presenting only one physical mode. The same holds for the scalar propagator. A consistency analysis is performed based on the poles of the propagators. The isotropic parity-even sector is stable, causal and unitary mode for 0{<=}{kappa}{sub 00}<1. On the other hand, the anisotropic sector is stable and unitary but in general noncausal. Finally, it is shown that this planar model interacting with a {lambda}{phi}{sup 4}-Higgs field supports compact-like vortex configurations. (orig.)
Consistency analysis of a nonbirefringent Lorentz-violating planar model
Casana, Rodolfo; Ferreira, Manoel M.; Moreira, Roemir P. M.
2012-07-01
In this work analyze the physical consistency of a nonbirefringent Lorentz-violating planar model via the analysis of the pole structure of its Feynman propagators. The nonbirefringent planar model, obtained from the dimensional reduction of the CPT-even gauge sector of the standard model extension, is composed of a gauge and a scalar fields, being affected by Lorentz-violating (LIV) coefficients encoded in the symmetric tensor κ μν . The propagator of the gauge field is explicitly evaluated and expressed in terms of linear independent symmetric tensors, presenting only one physical mode. The same holds for the scalar propagator. A consistency analysis is performed based on the poles of the propagators. The isotropic parity-even sector is stable, causal and unitary mode for 0≤ κ 00<1. On the other hand, the anisotropic sector is stable and unitary but in general noncausal. Finally, it is shown that this planar model interacting with a λ| φ|4-Higgs field supports compactlike vortex configurations.
Abraham-Lorentz-Dirac Equation in 5D Stuekelberg Electrodynamics
Land, Martin
2016-01-01
We derive the Abraham-Lorentz-Dirac (ALD) equation in the framework of the electrodynamic theory associated with Stueckelberg manifestly covariant canonical mechanics. In this framework, a particle worldline is traced out through the evolution of an event $x^\\mu(\\tau)$. By admitting unconstrained commutation relations between the positions and velocities, the associated electromagnetic gauge fields are in general dependent on the parameter $\\tau$, which plays the role of time in Newtonian mechanics. Standard Maxwell theory emerges from this system as a $\\tau$-independent equilibrium limit. In this paper, we calculate the $\\tau$-dependent field induced by an arbitrarily evolving event, and study the long-range radiation part, which is seen to be an on-shell plane wave of the Maxwell type. Following Dirac's method, we obtain an expression for the finite part of the self-interaction, which leads to the ALD equation that generalizes the Lorentz force. This third-order differential equation is then converted to an...
Extended Linear and Nonlinear Lorentz Transformations and Superluminality
Directory of Open Access Journals (Sweden)
Dara Faroughy
2013-01-01
Full Text Available Two broad scenarios for extended linear Lorentz transformations (ELTs are modeled in Section 2 for mixing subluminal and superluminal sectors resulting in standard or deformed energy-momentum dispersions. The first scenario is elucidated in the context of four diverse realizations of a continuous function f ( v , with 0 ≤ f ( v ≤ 1 and f ( 0 = f ( c = 1 , which is fitted in the ELT. What goes in the making of the ELT in this scenario is not the boost speed v , as ascertained by two inertial observers in uniform relative motion (URM, but v × f ( v . The second scenario infers the preexistence of two rest-mass-dependent superluminal speeds whereby the ELTs are finite at the light speed c . Particle energies are evaluated in this scenario at c for several particles, including the neutrinos, and are auspiciously found to be below the GKZ energy cutoff and in compliance with a host of worldwide ultrahigh energy cosmic ray data. Section 3 presents two broad scenarios involving a number of novel nonlinear LTs (NLTs featuring small Lorentz invariance violations (LIVs, as well as resurrecting the notion of simultaneity for limited spacetime events as perceived by two observers in URM. These inquiries corroborate that NLTs could be potent tools for investigating LIVs past the customary LTs.
Lorentz violation, two-time physics, and strings
Energy Technology Data Exchange (ETDEWEB)
Romero, Juan M., E-mail: jromero@correo.cua.uam.mx [Departamento de Matematicas Aplicadas y Sistemas, Universidad Autonoma Metropolitana-Cuajimalpa, Mexico, D.F 01120 (Mexico); Sanchez-Santos, Oscar, E-mail: oscarsanbuzz@yahoo.com.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico 04510 DF (Mexico); Vergara, Jose David, E-mail: vergara@nucleares.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico 04510 DF (Mexico)
2011-10-24
The aim of this paper is to study the generalization of the relativistic particle recently proposed by Kostelecky. An alternative action for this system is presented, and it is shown that this action can be interpreted as a particle in curved space. Furthermore, the following results are established for the model: (i) there exists a limit where the system has more local symmetries than the usual relativistic particle; (ii) in this limit when Lorentz symmetry is restored, a direct relationship with the two-time physics is determined; (iii) if also Poincare symmetry is recovered, the action of a relativistic bosonic string is obtained. -- Highlights: → We study the generalization of the relativistic particle proposed by Kostelecky. → An alternative action for this system is presented. → There is a limit where the model has more symmetries than the relativistic particle. → When Lorentz symmetry is restored, a relationship with two-time physics is determined. → If Poincare symmetry is recovered, the action of a relativistic string is obtained.
Photospheric Flows, Lorentz Forces, and Solar-Eruption Initiation
Fisher, George; Kazachenko, Maria
Eruptive Flares and coronal mass ejections (CMEs) are almost certainly magnetically driven. We discuss the role that the Lorentz force must play in driving an eruption, and how both the radial and horizontal components of this force can be related to changes that occur in observations of the vector magnetic field observed at the photosphere. We then review recent observational work on observed flows in the solar atmosphere, and how these flows might be related to changes in the Lorentz force observed during flares. Flows in magnetized regions of the photosphere also generate electric fields, which can affect the flux of magnetic energy transported across the photosphere and into the chromosphere and corona, and result in changes to the magnetic field there as well. We will discuss how such electric fields are incorporated into models of active-regions, to study the buildup of electric currents and the ejection of plasma in the context of our recently funded project, the ``Coronal Global Evolutionary Model (CGEM)'', a collaboration between UC Berkeley, Stanford University, and the Lockheed Martin Solar and Astrophysics Laboratory.
Aspects of semilocal BPS vortex in systems with Lorentz symmetry breaking
Energy Technology Data Exchange (ETDEWEB)
Villalobos, C.H.C.; Silva, J.M.H. da; Hott, M.B. [UNESP, Univ Estadual Paulista, Departamento de Fisica e Quimica, Guaratingueta, SP (Brazil); Belich, H. [Universidade Federal do Espi rito Santo (UFES), Departamento de Fisica e Quimica, Vitoria, ES (Brazil)
2014-03-15
The existence is shown of a static self-dual semilocal vortex configuration for the Maxwell-Higgs system with a Lorentz-violating CPT-even term. The dependence of the vorticity upper limit on the Lorentz-symmetry-breaking term is also investigated. (orig.)
Extending the graviton propagator with a Lorentz-violating vector field
Seifert, Michael D
2016-01-01
I discuss progress towards "bootstrapping" a Lorentz-violating gravity theory: namely, extending a linear Lorentz-violating theory of a rank-2 tensor to a non-linear theory by coupling this field to its own stress-energy tensor.
The ambiguity-free four-dimensional Lorentz-breaking Chern-Simons action
Energy Technology Data Exchange (ETDEWEB)
Brito, F.A. [Departamento de Fisica, Universidade Federal de Campina Grande, Caixa Postal 10071, 58109-970 Campina Grande, Paraiba (Brazil); Nascimento, J.R.; Passos, E. [Departamento de Fisica, Universidade Federal da Paraiba, Caixa Postal 5008, 58051-970 Joao Pessoa, Paraiba (Brazil); Petrov, A.Yu. [Departamento de Fisica, Universidade Federal da Paraiba, Caixa Postal 5008, 58051-970 Joao Pessoa, Paraiba (Brazil)], E-mail: petrov@fisica.ufpb.br
2008-06-12
The four-dimensional Lorentz-breaking finite and determined Chern-Simons like action is generated as a one-loop perturbative correction via an appropriate Lorentz-breaking coupling of the gauge field with the spinor field. Unlike the known schemes of calculations, within this scheme this term is found to be regularization independent.
Relativistic Landau-Aharonov-Casher quantization based on the Lorentz symmetry violation background
Bakke, K; Silva, E O; 10.1063/1.3597230
2011-01-01
Based on the discussions about the Aharonov-Casher effect in the Lorentz symmetry violation background, we show that the analogue of the relativistic Landau quantization in the Aharonov-Casher setup can be achieved in the Lorentz-symmetry violation background.
Relativistic Landau-Aharonov-Casher quantization based on the Lorentz symmetry violation background
Bakke, K.; Belich, H.; Silva, E. O.
2011-06-01
Based on the discussions about the Aharonov-Casher effect in the Lorentz symmetry violation background, we show that the analogue of the relativistic Landau quantization in the Aharonov-Casher setup can be achieved in the Lorentz-symmetry violation background.
Search for Lorentz and CPT violation effects in muon spin precession
Bennett, G. W.; Bousquet, B.; Brown, H. N.; Bunce, G.; Carey, R. M.; Cushman, P.; Danby, G. T.; Debevec, P. T.; Deile, M.; Deng, H.; Deninger, W.; Dhawan, S. K.; Druzhinin, V. P.; Duong, L.; Efstathiadis, E.; Farley, F. J. M.; Fedotovich, G. V.; Giron, S.; Gray, F. E.; Grigoriev, D.; Grosse-Perdekamp, M.; Grossmann, A.; Hare, M. F.; Hertzog, D. W.; Huang, X.; Hughes, V. W.; Iwasaki, M.; Jungmann, K.; Kawall, D.; Kawamura, M.; Khazin, B. I.; Kindem, J.; Krienen, F.; Kronkvist, I.; Lam, A.; Larsen, R.; Lee, Y. Y.; Logashenko, I.; McNabb, R.; Meng, W.; Mi, J.; Miller, J. P.; Mizumachi, Y.; Morse, W. M.; Nikas, D.; Onderwater, C. J. G.; Orlov, Y.; Oezben, C. S.; Paley, J. M.; Peng, Q.; Polly, C. C.; Pretz, J.; Prigl, R.; Putlitz, G. zu; Qian, T.; Redin, S. I.; Rind, O.; Roberts, B. L.; Ryskulov, N.; Sedykh, S.; Semertzidis, Y. K.; Shagin, P.; Shatunov, Yu. M.; Sichtermann, E. P.; Solodov, E.; Sossong, M.; Steinmetz, A.; Sulak, L. R.; Timmermans, C.; Trofimov, A.; Urner, D.; von Walter, P.; Warburton, D.; Winn, D.; Yamamoto, A.; Zimmerman, D.; Bennet, G.W.; Ozben, C.
2008-01-01
The spin precession frequency of muons stored in the (g-2) storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for a nonzero Delta omega(a)(=omega(mu+)(a)-omega(mu-)(a)) and a sidereal variation of omega(mu+)(a). No signifi
Implications of Lorentz violation on Higgs-mediated lepton flavor violation
López-Osorio, M A; Toscano, J J
2014-01-01
The lepton flavor violating decay of the Higgs boson $H\\to l_Al_B$ is studied within two qualitatively different extensions of the Yukawa sector: one renormalizable and the other nonrenormalizable; both incorporating Lorentz violation in a model-independent fashion. These extensions are characterized by Yukawa-like matrices, the former by a constant Lorentz 2-tensor $Y^{AB}_{\\mu \
Testing Lorentz invariance in the weak interaction using laser-polarized {sup 20}Na
Energy Technology Data Exchange (ETDEWEB)
Dijck, Elwin A.; Sytema, Auke; Mueller, Stefan E.; Hoekstra, Steven; Jungmann, Klaus; Noordmans, Jacob P.; Onderwater, Gerco; Pijpker, Coen; Timmermans, Rob G.E.; Willmann, Lorenz; Wilschut, Hans W. [University of Groningen (Netherlands)
2014-07-01
Lorentz invariance is one of the fundamental principles underlying our current understanding of nature. In models aiming to unify the Standard Model with (quantum) gravity this symmetry may be broken. Few tests of Lorentz invariance in the weak interaction have been made. We have performed a novel test of rotational invariance by searching for variations in the decay rate of {sup 20}Na nuclei depending on the nuclear spin orientation with respect to a possible Lorentz symmetry breaking background field. Using optical pumping, the nuclei were alternately polarized in opposite vertical directions, while the absolute orientation of the spins changed with the rotation of the Earth. A polarization-dependent Lorentz symmetry violating effect was searched for, putting a 95% confidence limit on the amplitude of sidereal variations in the decay rate asymmetry at < 3 x 10{sup -3}. This result was analyzed in the framework of a recently developed theory that assumes a Lorentz symmetry breaking background field of tensor nature.
The role of singular spinor fields in a torsional gravity, Lorentz-violating, framework
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.
The role of singular spinor fields in a torsional gravity, Lorentz-violating, framework
Ferrari, A F; Silva-Neto, J A
2016-01-01
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 sp...
High quality factor, fully switchable terahertz superconducting metasurface
Energy Technology Data Exchange (ETDEWEB)
Scalari, G., E-mail: scalari@phys.ethz.ch; Maissen, C.; Faist, J. [Institute of Quantum Electronics, Eidgenössische Technische Hochschule Zürich (Switzerland); Cibella, S.; Leoni, R. [Istituto di Fotonica e Nanotecnologie (IFN), CNR, via Cineto Romano 42, 00156 Rome (Italy)
2014-12-29
We present a complementary THz metasurface realised with Niobium thin film which displays a quality factor Q = 54 and a fully switchable behaviour as a function of the temperature. The switching behaviour and the high quality factor are due to a careful design of the metasurface aimed at maximising the ohmic losses when the Nb is above the critical temperature and minimising the radiative coupling. The superconductor allows the operation of the cavity with high Q and the use of inductive elements with a high aspect ratio. Comparison with three dimensional finite element simulations highlights the crucial role of the inductive elements and of the kinetic inductance of the Cooper pairs in achieving the high quality factor and the high field enhancement.
Testing Lorentz Invariance with Neutrinos from Ultrahigh Energy Cosmic Ray Interactions
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.
New limit on Lorentz violation using a double-pass optical ring cavity.
Michimura, Yuta; Matsumoto, Nobuyuki; Ohmae, Noriaki; Kokuyama, Wataru; Aso, Yoichi; Ando, Masaki; Tsubono, Kimio
2013-05-17
A search for Lorentz violation in electrodynamics was performed by measuring the resonant frequency difference between two counterpropagating directions of an optical ring cavity. Our cavity contains a dielectric element, which makes our cavity sensitive to the violation. The laser frequency is stabilized to the counterclockwise resonance of the cavity, and the transmitted light is reflected back into the cavity for resonant frequency comparison with the clockwise resonance. This double-pass configuration enables a null experiment and gives high common mode rejection of environmental disturbances. We found no evidence for odd-parity anisotropy at the level of δc/c ≲ 10(-14). Within the framework of the standard model extension, our result put more than 5 times better limits on three odd-parity parameters κ(o+)(JK) and a 12 times better limit on the scalar parameter κ(tr) compared with the previous best limits.
Design and simulation of superconducting Lorentz Force Electrical Impedance Tomography (LFEIT)
Shen, Boyang; Fu, Lin; Geng, Jianzhao; Zhang, Xiuchang; Zhang, Heng; Dong, Qihuan; Li, Chao; Li, Jing; Coombs, T. A.
2016-05-01
Lorentz Force Electrical Impedance Tomography (LFEIT) is a hybrid diagnostic scanner with strong capability for biological imaging, particularly in cancer and haemorrhages detection. This paper presents the design and simulation of a novel combination: a superconducting magnet together with LFEIT system. Superconducting magnets can generate magnetic field with high intensity and homogeneity, which could significantly enhance the imaging performance. The modelling of superconducting magnets was carried out using Finite Element Method (FEM) package, COMSOL Multiphysics, which was based on Partial Differential Equation (PDE) model with H-formulation coupling B-dependent critical current density and bulk approximation. The mathematical model for LFEIT system was built based on the theory of magneto-acoustic effect. The magnetic field properties from magnet design were imported into the LFEIT model. The basic imaging of electrical signal was developed using MATLAB codes. The LFEIT model simulated two samples located in three different magnetic fields with varying magnetic strength and homogeneity.
Sekalski, S P; Sekalski, S P
2004-01-01
To reach high gradients in pulsed operation of superconducting (SC) cavities an active Lorentz force detuning compensation system is needed. For this system a piezoelement can be used as an actuator (other option is a magnetostrictive device). To guarantee the demanded lifetime of the active element, the proper preload force adjustment is necessary. To determine this parameter an absolute force sensor is needed which will be able to operate at cryogenic temperatures. Currently, there is no calibrated commercial available sensor, which will be able to measure the static force in such an environment. The authors propose to use a discovered phenomenon to estimate the preload force applied to the piezoelement. The principle of the proposed solution based on a shape of impedance curve, which changes with the value of applied force. Especially, the position of resonances are monitored. No need of specialized force sensor and measurement in-situ are additional advantages of proposed method.
Constraining the Lorentz invariance violation from the continuous spectra of short gamma-ray bursts
Chang, Zhe; Lin, Hai-Nan; Sang, Yu; Wang, Ping; Wang, Sai
2015-01-01
In quantum gravity, a foamy structure of space-time leads to Lorentz invariance violation (LIV). As the most energetic astrophysical processes in the Universe, gamma-ray bursts (GRBs) provide an effective way to probe quantum gravity effects. We use continuous spectra of 20 short GRBs detected by the Swift satellite to give a conservative lower limit of quantum gravity energy scale $M_\\textrm{QG} $. Due to the LIV effect, photons with different energy have different velocities. This will lead to the delayed arrival of high energy photons relative to the low energy ones. Based on the fact that the LIV-induced time delay can't be longer than the duration of a GRB, we present the most conservative estimation of the quantum gravity energy scales from 20 short GRBs. The most strict constraint, $M_\\textrm{QG}>5.05\\times10^{14}$ GeV, is from GRB 140622A.
Extremely high Q -factor metamaterials due to anapole excitation
Basharin, Alexey A.; Chuguevsky, Vitaly; Volsky, Nikita; Kafesaki, Maria; Economou, Eleftherios N.
2017-01-01
We have designed and fabricated a metamaterial consisting of planar metamolecules which exhibit unusual, almost perfect anapole behavior in the sense that the electric dipole radiation is almost canceled by the toroidal dipole one, producing thus an extremely high Q -factor at the resonance frequency. Thus we have demonstrated theoretically and experimentally that metamaterials approaching ideal anapole behavior have very high Q -factor. The size of the system, at the millimeter range, and the parasitic magnetic quadrupole radiation are the factors limiting the size of the Q -factor. In spite of the very low radiation losses the estimated local fields at the metamolecules are extremely high, of the order of 104 higher than the external incoming field.
Learner Factors in a High-Poverty Urban Middle School
Olivares-Cuhat, Gabriela
2011-01-01
The purpose of this pilot study is to gain more insight into learner factors prominent in high-poverty urban schools and to suggest pedagogical approaches appropriate to this environment. To this end, three surveys were administered to students attending a high-poverty, urban middle school in order to measure their learning style preferences,…
Time-Varying Metasurfaces and Lorentz Non-Reciprocity
Shaltout, Amr; Shalaev, Vladimir
2015-01-01
A cornerstone equation of optics, Snell's law, relates the angles of incidence and refraction for light passing through an interface between two media. It is built on two fundamental constrains: the conservation of tangential momentum and the conservation of energy. By relaxing the classical Snell law photon momentum conservation constrain when using space-gradient phase discontinuity, optical metasurfaces enabled an entirely new class of ultrathin optical devices. Here, we show that by eradicating the photon energy conservation constrain when introducing time-gradient phase discontinuity, we can further empower the area of flat photonics and obtain a new genus of optical devices. With this approach, classical Snell relations are developed into a more universal form not limited by Lorentz reciprocity, hence, meeting all the requirements for building magnetic-free optical isolators. Furthermore, photons experience inelastic interaction with time-gradient metasurfaces, which modifies photonic energy eigenstates...
An acoustic spacetime and the Lorentz transformation in aeroacoustics
Gregory, Alastair Logan; Agarwal, Anurag; Lasenby, Joan
2014-01-01
This paper introduces acoustic space-time and Geometric Algebra as a new theoretical framework for modelling aeroacoustic phenomena. This new framework is applied to sound propagation in uniform flows. The problem is modelled by means of transformations that turn the convected wave equation into an ordinary wave equation, in either time-space coordinates or frequency-wavenumber coordinates. The transformations are shown to combine a Galilean transformation with a Lorentz transformation and geometrical and physical interpretations are provided. The Lorentzian frame is the natural frame for describing acoustic waves in uniform flow. A key feature of this frame is that it combines space and time in a way that is best described using a hyperbolic geometry. The power of this new theoretical framework is illustrated by providing simple derivations for two classical aeroacoustic problems: the free-field Greens function for the convected wave equation and the Doppler shift for a stationary observer and a source in un...
Collective Lorentz invariant dynamics on a single "polynomial" worldline
Kassandrov, Vladimir V; Markova, Nina V
2015-01-01
Consider a worldline of a pointlike particle parametrized by polynomial functions, together with the light cone ("retardation") equation of an inertially moving observer. Then a set of apparent copies ("duplicons") of the single pointlike particle defined by the roots of the retardation equation and localized on one and the same worldline will be detected by the observer. We prove that for any "polynomial" worldline the induced collective dynamics of duplicons 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 duplicons split themselves into pairs ("first phase transition") a...
Cosmic Censorship in Lorentz Violating Theories of Gravity
Meiers, Michael; Afshordi, Niayesh
2015-01-01
Is Cosmic Censorship special to General Relativity, or can it survive a violation of equivalence principle? Recent studies have shown that singularities in Lorentz violating Einstein-Aether (or Horava-Lifhsitz) 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+1d 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 theorie...
Modified Einstein and Finsler Like Theories on Tangent Lorentz Bundles
Stavrinos, Panayiotis; Vacaru, Sergiu I.
2014-01-01
We study modifications of general relativity, GR, with nonlinear dispersion relations which can be geometrized on tangent Lorentz bundles. Such modified gravity theories, MGTs, can be modeled by gravitational Lagrange density functionals $f(\\mathbf{R},\\mathbf{T},F)$ with generalized/ modified scalar curvature $\\mathbf{R}$, trace of matter field tensors $\\mathbf{T}$ and modified Finsler like generating function $F$. In particular, there are defined extensions of GR with extra dimensional "velocity/ momentum" coordinates. For four dimensional models, we prove that it is possible to decouple and integrate in very general forms the gravitational fields for $f(\\mathbf{R},\\mathbf{T},F)$--modified gravity using nonholonomic 2+2 splitting and nonholonomic Finsler like variables $F$. We study the modified motion and Newtonian limits of massive test particles on nonlinear geodesics approximated with effective extra forces orthogonal to the four-velocity. We compute the constraints on the magnitude of extra-acceleration...
Low energy Lorentz violation from polymer quantum field theory
Husain, Viqar
2015-01-01
We analyze the response of an inertial two-level Unruh-DeWitt particle detector coupled to a polymer quantized scalar field in four-dimensional Minkowski spacetime, within first-order perturbation theory. Above a critical rapidity $\\beta_c \\approx 1.3675$, independent of the polymer mass scale $M_\\star$, two drastic changes occur: (i) the detector's excitation rate becomes nonvanishing; (ii) the excitation and de-excitation rates are of order $M_\\star$, for arbitrarily small detector energy gap. We argue that qualitatively similar results hold for any Lorentz violating theory in which field modes with spatial momentum $k$ have excitation energy of the form $|k|\\ f(|k|/M_\\star)$ where the function $f$ dips below unity.
Signals for Lorentz Violation in Post-Newtonian Gravity
Bailey, Q G; Bailey, Quentin G.; Kostelecky, Alan
2006-01-01
The pure-gravity sector of the minimal Standard-Model Extension is studied in the limit of Riemann spacetime. A method is developed to extract the modified Einstein field equations in the limit of small metric fluctuations about the Minkowski vacuum, while allowing for the dynamics of the coefficients for Lorentz violation. The linearized effective equations depend on 20 independent coefficients, and they are solved to obtain the post-newtonian metric. The corresponding post-newtonian behavior of a perfect fluid is studied and applied to the gravitating many-body system. Illustrative examples of the methodology are provided using bumblebee models. The implications of the general theoretical results are studied for a variety of existing and proposed gravitational experiments, including lunar and satellite laser ranging, laboratory experiments with gravimeters and torsion pendula, measurements of the spin precession of orbiting gyroscopes, timing studies of signals from binary pulsars, and the classic tests inv...
Lorentz violating p-form gauge theories in superspace
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.
Proposed test of Lorentz Invariance using the Gravitational Wave Interferometers
Melissinos, Adrian C
2016-01-01
Current limits on violation of local Lorentz invariance in the photon sector are derived mainly from experiments that search for a spatial anisotropy in the speed of light. The presently operating gravitational wave detectors are Michelson interferometers with long effective arms, 4e5 m, and sensitive to a fringe shift 2e-9. Therefore they can be used to test for a difference in the speed of light in the two arms, as modulated bi-annualy by the orientation of the Earth's velocity with respect to the direction of motion of the local system. A limit can be set on the Robertson-Mansouri-Sexl parameter PMM < 10e-15, as compared to its present limit of PMM < 2e-10, an improvement of five orders of magnitude.
Lorentz effect imaging of ionic currents in solution
Truong, Trong-Kha; Avram, Alexandru; Song, Allen W.
2008-03-01
Current functional MRI techniques relying on hemodynamic modulations are inherently limited in their ability to accurately localize neural activity in space and time. To address these limitations, we previously proposed a novel technique based on the Lorentz effect and demonstrated its ability to directly image minute electrical activity with a millisecond temporal resolution in gel phantoms containing conductive wires as well as in the human median nerve in vivo. To better characterize its contrast mechanism and ultimately further improve its sensitivity for in vivo applications, we now apply this technique to image ionic currents in solution, which serve as a better model for neural conduction in biological systems than the electronic currents in conductive wires used in previous phantom studies. Our results demonstrate that ionic currents with durations and current densities on the same order of magnitude as those induced by neuroelectric activity in nerve fibers and in the brain can be detected.
Test of Lorentz invariance with spin precession of ultracold neutrons
Altarev, I; Ban, G; Bison, G; Bodek, K; Daum, M; Fierlinger, P; Geltenbort, P; Green, K; van der Grinten, M G D; Gutsmiedl, E; Harris, P G; Heil, W; Henneck, R; Horras, M; Iaydjiev, P; Ivanov, S N; Khomutov, N; Kirch, K; Kistryn, S; Knecht, A; Knowles, P; Kozela, A; Kuchler, F; Kuźniak, M; Lauer, T; Lauss, B; Lefort, T; Mtchedlishvili, A; Naviliat-Cuncic, O; Pazgalev, A; Pendlebury, J M; Petzoldt, G; Pierre, E; Pignol, G; Quéméner, G; Rebetez, M; Rebreyend, D; Roccia, S; Rogel, G; Severijns, N; Shiers, D; Sobolev, Yu; Weis, A; Zejma, J; Zsigmond, G
2009-01-01
A clock comparison experiment, analyzing the ratio of spin precession frequencies of stored ultracold neutrons and 199Hg 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 < 2 * 10^{-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_n| < 0.3 eV.c^{-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_n| < 3 * 10^{-4} eV.c^{-2}.m.
Lorentz violating p-form gauge theories in superspace
Energy Technology Data Exchange (ETDEWEB)
Upadhyay, Sudhaker [Indian Institute of Technology Kharagpur, Centre for Theoretical Studies, Kharagpur (India); Shah, Mushtaq B.; Ganai, Prince A. [National Institute of Technology, Department of Physics, Srinagar, Kashmir (India)
2017-03-15
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. (orig.)
Renormalization of a Lorentz invariant doubled worldsheet theory
Nibbelink, Stefan Groot; Patalong, Peter
2013-01-01
Manifestly T-duality covariant worldsheet string models can be constructed by doubling the coordinate fields. We describe the underlying gauge symmetry of a recently proposed Lorentz invariant doubled worldsheet theory that makes half of the worldsheet degrees of freedom redundant. By shifting the Lagrange multiplier, that enforces the gauge fixing condition, the worldsheet action can be cast into various guises. We investigate the renormalization of this theory using a non-linear background/quantum split by employing a normal coordinate expansion adapted to the gauge-fixed theory. The propagator of the doubled coordinates contains a projection operator encoding that half of them do not propagate. We determine the doubled target space equations of motion by requiring one-loop Weyl invariance. Some of them are generalizations of the conventional sigma model beta-functions, while others seem to be novel to the doubled theory: In particular, a dilaton equation seems related to the strong constraint of double fie...
An Off Diagonal Marcinkiewicz Interpolation Theorem on Lorentz Spaces
Institute of Scientific and Technical Information of China (English)
Yi Yu LIANG; Li Guang LIU; Da Chun YANG
2011-01-01
Let(X,μ)be a measure space.In this paper,using some ideas from Grafakos and Kalton,the authors establish an of diagonal Marcinkiewicz interpolation theorem for a quasilinear operator T in Lorentz spaces Lp,q(X)with p,q∈(0,∞],which is a corrected version of Theorem 1.4.19 in[Grafakos,L.:Classical Fourier Analysis,Second Edition,Graduate Texts in Math.,No.249,Springer,New York,2008]and which,in the case that T is linear or nonnegative sublineaa,P∈[1,∞)and q∈[1,∞),was obtained by Stein and Weiss [Introduction to Fourier Analysis on Euclidean Spaces,Princeton University Press,Princeton,N.J.,1971].
Lorentz violation in the gravity sector: the t puzzle
Bonder, Yuri
2015-01-01
Lorentz violation is a candidate quantum-gravity signal, and the Standard-Model Extension (SME) is a widely used parametrization of such violation. In the gravitational SME sector, there is an elusive coefficient for which no effects have been found. This is is known as the $t$ puzzle and, to date, it has no compelling explanation. In this paper, several approaches to understand the $t$ puzzle are proposed. First, redefinitions of the dynamical fields are studied, which reveal that other SME coefficients can be moved to nongravitational sectors. It is also shown that the gravity SME sector can be treated \\textit{\\`a la} Palatini, and that, in the presence of spacetime boundaries, it is possible to correct its action to get the desired equations of motion. Also, through a reformulation as a Lanczos-type tensor, some problematic features of the $t$ term, that should arise at the phenomenological level, are revealed. Additional potential explanations to the $t$ puzzle are outlined.
Diffusion in the two-dimensional nonoverlapping Lorentz gas
James, Corinne P.; Evans, Glenn T.
1987-10-01
The self-diffusion coefficient, velocity autocorrelation function, and distribution of collision times for a two-dimensional nonoverlapping Lorentz gas were calculated using molecular dynamics simulation. The systems studied covered a range of densities, from a packing fraction (πNr2/L2) of 0.01 to 0.8. Self-diffusion coefficients were found to agree to all densities with kinetic theory predictions [A. Weijland and J. M. J. van Leeuwen, Physica 38, 35 (1968)] if the radial distribution function (rdf) was taken into account. The density dependence of the decay of the velocity autocorrelation function was qualitatively different from that predicted by kinetic theory. The distribution of collision times was nearly exponential for all but the highest density studied.
Chiral Dynamics of Baryons in a Lorentz Covariant Quark Model
Faessler, A; Lyubovitskij, V E; Pumsa-ard, K; Faessler, Amand; Gutsche, Th.
2006-01-01
We develop a manifestly Lorentz covariant chiral quark model for the study of baryons as bound states of constituent quarks dressed by a cloud of pseudoscalar mesons. The approach is based on a non-linear chirally symmetric Lagrangian, which involves effective degrees of freedom - constituent quarks and the chiral (pseudoscalar meson) fields. In a first step, this Lagrangian can be used to perform a dressing of the constituent quarks by a cloud of light pseudoscalar mesons and other heavy states using the calculational technique of infrared dimensional regularization of loop diagrams. We calculate the dressed transition operators with a proper chiral expansion which are relevant for the interaction of quarks with external fields in the presence of a virtual meson cloud. In a second step, these dressed operators are used to calculate baryon matrix elements. Applications are worked out for the masses of the baryon octet, the meson-nucleon sigma terms, the magnetic moments of the baryon octet, the nucleon charge...
Massive photons from Super and Lorentz symmetry breaking
Bonetti, Luca; Helayël-Neto, José A; Spallicci, Alessandro D A M
2016-01-01
In the context of Standard Model Extensions (SMEs), we analyse four general classes of Super Symmetry (SuSy) and Lorentz Symmetry (LoSy) breaking, leading to {observable} imprints at our energy scales. The photon dispersion relations show a non-Maxwellian behaviour for the CPT (Charge-Parity-Time reversal symmetry) odd and even sectors. The group velocities exhibit also a directional dependence with respect to the breaking background vector (odd CPT) or tensor (even CPT). In the former sector, the group velocity may decay following an inverse squared frequency behaviour. Thus, we extract a massive and gauge invariant Carroll-Field-Jackiw photon term in the Lagrangian and show that the mass is proportional to the breaking vector. The latter is estimated by ground measurements and leads to a photon mass upper limit of $10^{-19}$ eV or $2 \\times 10^{-55}$ kg and thereby to a potentially measurable delay at low radio frequencies.
Violations of Lorentz invariance in the neutrino sector after OPERA
Energy Technology Data Exchange (ETDEWEB)
Maccione, Luca [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Liberati, Stefano [Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste (Italy); INFN, Sezione de Trieste (Italy); Mattingly, David M. [New Hampshire Univ., Durham (United States). Dept. of Physics
2011-10-15
The OPERA collaboration has recently reported that neutrinos travel faster than light. We review the theoretical situation of constraints on violations of Lorentz invariance, focusing in particular on the compatibility between the OPERA results with both previous constraints and recently obtained ones. We generalize to higher order operators the recent constraint provided by the absence of neutrino energy loss, via electron-positron pair production at OPERA energies, and show that no modi ed in vacuo dispersion relation within an effective field theory context is compatible with OPERA results. We conclude that the OPERA result is incompatible with current observations, at least without resorting to models beyond effective field theory, possibly with local environmental effects. (orig.)
Cosmological background torsion inhomogeneities and Lorentz violation in QED
Garcia de Andrade, L C
2003-01-01
A non-minimal photon-torsion axial coupling in the quantum electrodynamics (QED) framework is considered. The geometrical optics in Riemann-Cartan spacetime is considering and a plane wave expansion of the electromagnetic vector potential is considered leading to a set of the equations for the ray congruence. Since we are interested mainly on the torsion effects in this first report we just consider the Riemann-flat case composed of the Minkowskian spacetime with torsion. It is also shown that in torsionic de Sitter background the vacuum polarisation does alter the propagation of individual photons, an effect which is absent in Riemannian spaces. It is shown that the cosmological torsion background inhomogeneities induce Lorentz violation and massive photon modes in this QED.
Smoking and Its Related Factors Among Iranian High School Students
Chaman, Reza; Khosravi, Ahmad; Sajedinejad, Sima; Nazemi, Saeed; Fereidoon Mohasseli, Khadije; Valizade, Behzad; Vahedi, Hamid; Hosseinzadeh, Ehsan; Amiri, Mohammad
2015-01-01
Background: In different studies, the prevalence of tobacco consumption has been growing in high schools boys. Objectives: This study was conducted to determine the prevalence of smoking and its related factors among Iranian high school students in 2011. Materials and Methods: In this cross-sectional study, 450 male students from 15 high schools of Shahroud (northeast of Iran) were selected for evaluation of the knowledge, attitude and practices (KAP) of students regarding tobacco consumption...
HIGH DIMENSIONAL COVARIANCE MATRIX ESTIMATION IN APPROXIMATE FACTOR MODELS.
Fan, Jianqing; Liao, Yuan; Mincheva, Martina
2011-01-01
The variance covariance matrix plays a central role in the inferential theories of high dimensional factor models in finance and economics. Popular regularization methods of directly exploiting sparsity are not directly applicable to many financial problems. Classical methods of estimating the covariance matrices are based on the strict factor models, assuming independent idiosyncratic components. This assumption, however, is restrictive in practical applications. By assuming sparse error covariance matrix, we allow the presence of the cross-sectional correlation even after taking out common factors, and it enables us to combine the merits of both methods. We estimate the sparse covariance using the adaptive thresholding technique as in Cai and Liu (2011), taking into account the fact that direct observations of the idiosyncratic components are unavailable. The impact of high dimensionality on the covariance matrix estimation based on the factor structure is then studied.
High-dimensional covariance matrix estimation in approximate factor models
Fan, Jianqing; Mincheva, Martina; 10.1214/11-AOS944
2012-01-01
The variance--covariance matrix plays a central role in the inferential theories of high-dimensional factor models in finance and economics. Popular regularization methods of directly exploiting sparsity are not directly applicable to many financial problems. Classical methods of estimating the covariance matrices are based on the strict factor models, assuming independent idiosyncratic components. This assumption, however, is restrictive in practical applications. By assuming sparse error covariance matrix, we allow the presence of the cross-sectional correlation even after taking out common factors, and it enables us to combine the merits of both methods. We estimate the sparse covariance using the adaptive thresholding technique as in Cai and Liu [J. Amer. Statist. Assoc. 106 (2011) 672--684], taking into account the fact that direct observations of the idiosyncratic components are unavailable. The impact of high dimensionality on the covariance matrix estimation based on the factor structure is then studi...
High Quality Factor Fano-Resonant All-Dielectric Metamaterials
Yang, Yuanmu; Briggs, Dayrl P; Valentine, Jason
2014-01-01
Fano-resonant plasmonic metamaterials and nanostructures have become a major focus of the nanophotonics fields over the past several years due their ability to produce high quality factor (Q-factor) resonances. The origin of such resonances is the interference between a broad and narrow resonance, ultimately allowing suppression of radiative damping. However, Fano-resonant plasmonic structures still suffer non-radiative damping due to Ohmic loss, ultimately limiting the achievable Q-factors to values less than 10. Here, we report experimental demonstration of Fano-resonant silicon-based metamaterials that have a response that mimics the electromagnetically induced transparency (EIT) found in atomic systems. Due to extremely low absorption loss, a record-high Q-factor of 306 was experimentally observed. Furthermore, the unit cell of the metamaterial was designed with a feed-gap which results in strong local field enhancement in the surrounding medium resulting in strong light-matter interaction. This allows th...
Relative dynamics and control of spacecraft formations subject to lorentz force perturbations
Abdel-Aziz, Yehia; Shoaib, Muhammad
A spacecraft that generates an electrostatic charge on its surface in the Earth magnetic field will be subject to a perturbative Lorentz force. The Lorentz force acting on an electrostatically charged spacecraft may provide a useful thrust for controlling a spacecraft’s orbit. We develop Lorentz force as a function of the orbital elements. The orbital perturbations of a charged spacecraft by Lorentz force in the Earth’s magnetic field are investigated using the Gauss variation of the Lagrange planetary Equations. The Earth’s magnetic field is modeled as a tilted dipole. The perturbations in the orbital elements depend on the value of the charge to mass ratio (q/m). The dynamical model of relative motion developed leads to approximate analytical solutions for the motion of a charged spacecraft subject to Lorentz force. The chief spacecraft’s reference orbit is taken to be either circular or elliptical. The deputy spacecraft is capable of accumulating electrostatic charge. The numerical results show that Lorentz force can be used to change the in-track position and plane orbit of the spacecraft. The numerical analysis shows that the target trajectory of the Lorentz spacecraft can be reached by varying the ratio (q/m) in different Low Earth Orbits.
Time-delay and Doppler tests of the Lorentz symmetry of gravity
Bailey, Quentin G
2009-01-01
Modifications to the classic time-delay effect and Doppler shift in General Relativity (GR) are studied in the context of the Lorentz-violating Standard-Model Extension (SME). We derive the leading Lorentz-violating corrections to the time-delay and Doppler shift signals, for a light ray passing near a massive body. It is demonstrated that anisotropic coefficients for Lorentz violation control a time-dependent behavior of these signals that is qualitatively different from the conventional case in GR. Estimates of sensitivities to gravity-sector coefficients in the SME are given for current and future experiments, including the recent Cassini solar conjunction experiment.
Lorentz-violating neutral-pion decays in isotropic modified Maxwell theory
Klinkhamer, F R
2016-01-01
We consider an extension of the Standard Model with isotropic nonbirefringent Lorentz violation in the photon sector and specialize to the case of a "fast" photon with a phase velocity larger than the maximum attainable velocity of the fermions. With our conventions, this case corresponds to a negative Lorentz-violating parameter $\\kappa$ in the action. The decay rate of a neutral pion into two photons is calculated as a function of the 3-momentum of the initial pion and the negative Lorentz-violating parameter $\\kappa$ of the final photons.
Searching for photon-sector Lorentz violation using gravitational-wave detectors
Kostelecky, Alan; Mewes, Matthew
2016-01-01
We study the prospects for using interferometers in gravitational-wave detectors as tools to search for photon-sector violations of Lorentz symmetry. Existing interferometers are shown to be exquisitely sensitive to tiny changes in the effective refractive index of light occurring at frequencies around and below the microhertz range, including at the harmonics of the frequencies of the Earth's sidereal rotation and annual revolution relevant for tests of Lorentz symmetry. We use preliminary data obtained by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in 2006-2007 to place constraints on coefficients for Lorentz violation in the photon sector exceeding current limits by about four orders of magnitude.
First Test of Lorentz Violation with a Reactor-based Antineutrino Experiment
Abe, Y; Anjos, J C dos; Bergevin, M; Bernstein, A; Bezerra, T J C; Bezrukhov, L; Blucher, E; Bowden, N S; Buck, C; Busenitz, J; Cabrera, A; Caden, E; Camilleri, L; Carr, R; Cerrada, M; Chang, P -J; Chimenti, P; Classen, T; Collin, A P; Conover, E; Conrad, J M; Crespo-Anadón, J I; Crum, K; Cucoanes, A; D'Agostino, M V; Damon, E; Dawson, J V; Dazeley, S; Dietrich, D; Djurcic, Z; Dracos, M; Durand, V; Ebert, J; Efremenko, Y; Elnimr, M; Erickson, A; Fallot, M; Fechner, M; von Feilitzsch, F; Felde, J; Fischer, V; Franco, D; Franke, A J; Franke, M; Furuta, H; Gama, R; Gil-Botella, I; Giot, L; Göger-Neff, M; Gonzalez, L F G; Goodman, M C; Goon, J TM; Greiner, D; Haag, N; Habib, S; Hagner, C; Hara, T; Hartmann, F X; Haser, J; Hatzikoutelis, A; Hayakawa, T; Hofmann, M; Horton-Smith, G A; Ishitsuka, M; Jochum, J; Jollet, C; Jones, C L; Kaether, F; Kalousis, L N; Kamyshkov, Y; Kaplan, D M; Katori, T; Kawasaki, T; Keefer, G; Kemp, E; de Kerret, H; Konno, T; Kryn, D; Kuze, M; Lachenmaier, T; Lane, C E; Lasserre, T; Letourneau, A; Lhuillier, D; Lima, H P; Lindner, M; López-Castanõ, J M; LoSecco, J M; Lubsandorzhiev, B K; Lucht, S; McKee, D; Maeda, J; Maesano, C N; Mariani, C; Maricic, J; Martino, J; Matsubara, T; Mention, G; Meregaglia, A; Meyer, M; Miletic, T; Milincic, R; Miyata, H; Mueller, Th A; Nagasaka, Y; Nakajima, K; Novella, P; Obolensky, M; Oberauer, L; Onillon, A; Osborn, A; Ostrovskiy, I; Palomares, C; Pepe, I M; Perasso, S; Perrin, P; Pfahler, P; Porta, A; Potzel, W; Pronost, G; Reichenbacher, J; Reinhold, B; Remoto, A; Röhling, M; Roncin, R; Roth, S; Rybolt, B; Sakamoto, Y; Santorelli, R; Sato, F; Schönert, S; Schoppmann, S; Schwetz, T; Shaevitz, M H; Shrestha, D; Sida, J -L; Sinev, V; Skorokhvatov, M; Smith, E; Spitz, J; Stahl, A; Stancu, I; Stokes, L F F; Strait, M; Stüken, A; Suekane, F; Sukhotin, S; Sumiyoshi, T; Sun, Y; Terao, K; Tonazzo, A; Toups, M; Thi, H H Trinh; Valdiviesso, G; Veyssiere, C; Wagner, S; Watanabe, H; White, B; Wiebusch, C; Winslow, L; Worcester, M; Wurm, M; Yanovitch, E; Yermia, F; Zimmer, V
2012-01-01
We present a search for Lorentz violation with 8249 candidate electron antineutrino events taken by the Double Chooz experiment in 227.9 live days of running. This analysis, featuring a search for a sidereal time dependence of the events, is the first test of Lorentz invariance using a reactor-based antineutrino source. No sidereal variation is present in the data and the disappearance results are consistent with sidereal time independent oscillations. Under the Standard-Model Extension (SME), we set the first limits on fourteen Lorentz violating coefficients associated with transitions between electron and tau flavor, and set two competitive limits associated with transitions between electron and muon flavor.
Traces of Lorentz symmetry breaking in a hydrogen atom at ground state
Borges, L. H. C.; Barone, F. A.
2016-02-01
Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schrödinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector.
Search for Lorentz and CPT Violation Effects in Muon Spin Precession
Bennett, G W; Brown, H N; Bunce, G; Carey, R M; Cushman, P; Danby, G T; Debevec, P T; Deile, M; Deng, H; Deninger, W; Dhawan, S K; Druzhinin, V P; Duong, L; Efstathiadis, E; Farley, F J M; Fedotovich, G V; Giron, S; Gray, F E; Grigoriev, D; Grosse-Perdekamp, M; Grossmann, A; Hare, M F; Hertzog, D W; Huang, X; Hughes, V W; Iwasaki, M; Jungmann, K; Kawall, D; Kawamura, M; Khazin, B I; Kindem, J; Krienen, F; Kronkvist, I; Lam, A; Larsen, R; Lee, Y Y; Logashenko, I; McNabb, R; Meng, W; Mi, J; Miller, J P; Mizumachi, Y; Morse, W M; Nikas, D; Onderwater, C J G; Orlov, Y; Ozben, C S; Paley, J M; Peng, Q; Polly, C C; Pretz, J; Prigl, R; zu Putlitz, G; Qian, T; Redin, S I; Rind, O; Roberts, B L; Ryskulov, N; Sedykh, S; Semertzidis, Y K; Shagin, P; Shatunov, Yu M; Sichtermann, E P; Solodov, E; Sossong, M; Steinmetz, A; Sulak, L R; Timmermans, C; Trofimov, A; Urner, D; von Walter, P; Warburton, D; Winn, D; Yamamoto, A; Zimmerman, D
2007-01-01
The spin precession frequency of muons stored in the (g-2) precision storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for: a nonzero \\Delta\\omega_a =\\omega_a ^\\mu^{+} - \\omega_{a}^\\mu^{-} ; and a sidereal variation of \\omega_{a}^\\mu^{\\pm}. No significant effect is found, and several limits on Lorentz and CPT violating parameters for positive and negative muons are set at the level of \\sim 10^{-23} - 10^{-24} GeV.
Traces of Lorentz symmetry breaking in a Hydrogen atom at ground state
Borges, Luiz Henrique de Campos
2016-01-01
Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the Hydrogen atom are investigated. It is used standard Rayleigh-Schr\\"odinger perturbation theory in order to obtain the corrections to the the ground state energy and wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in reference Eur. Phys. J. C {\\bf 74}, 2937 (2014), where the Lorentz symmetry is broken in the electromagnetic sector.
Asymptotic states and renormalization in Lorentz-violating quantum field theory
Cambiaso, Mauro; Potting, Robertus
2014-01-01
Asymptotic single-particle states in quantum field theories with small departures from Lorentz symmetry are investigated. To this end, one-loop radiative corrections for a sample Lorentz-violating Lagrangian contained in the Standard-Model Extension (SME) are studied. It is found that the spinor kinetic operator is modified in momentum space by Lorentz-violating operators not present in the original Lagrangian. It is demonstrated how both the standard renormalization procedure as well as the Lehmann-Symanzik-Zimmermann reduction formalism need to be adapted as a consequence of this result.
Traces of Lorentz symmetry breaking in a hydrogen atom at ground state
Energy Technology Data Exchange (ETDEWEB)
Borges, L.H.C. [Universidade Federal do ABC, Centro de Ciencias Naturais e Humanas, Santo Andre, SP (Brazil); Barone, F.A. [IFQ-Universidade Federal de Itajuba, Itajuba, MG (Brazil)
2016-02-15
Some traces of a specific Lorentz symmetry breaking scenario in the ground state of the hydrogen atom are investigated. We use standard Rayleigh-Schroedinger perturbation theory in order to obtain the corrections to the ground state energy and the wave function. It is shown that an induced four-pole moment arises, due to the Lorentz symmetry breaking. The model considered is the one studied in Borges et al. (Eur Phys J C 74:2937, 2014), where the Lorentz symmetry is broken in the electromagnetic sector. (orig.)
Cyberbullying and Its Risk Factors among Chinese High School Students
Zhou, Zongkui; Tang, Hanying; Tian, Yuan; Wei, Hua; Zhang, Fengjuan; Morrison, Chelsey M.
2013-01-01
Cyberbullying has become a common occurrence among adolescents worldwide; however, it has yet to receive adequate scholarly attention in China, especially in the mainland. The present study investigated the epidemiological characteristics and risk factors of cyberbullying, utilizing a sample of 1,438 high school students from central China.…
Cyberbullying and Its Risk Factors among Chinese High School Students
Zhou, Zongkui; Tang, Hanying; Tian, Yuan; Wei, Hua; Zhang, Fengjuan; Morrison, Chelsey M.
2013-01-01
Cyberbullying has become a common occurrence among adolescents worldwide; however, it has yet to receive adequate scholarly attention in China, especially in the mainland. The present study investigated the epidemiological characteristics and risk factors of cyberbullying, utilizing a sample of 1,438 high school students from central China.…
Factors Affecting Computer Anxiety in High School Computer Science Students.
Hayek, Linda M.; Stephens, Larry
1989-01-01
Examines factors related to computer anxiety measured by the Computer Anxiety Index (CAIN). Achievement in two programing courses was inversely related to computer anxiety. Students who had a home computer and had computer experience before high school had lower computer anxiety than those who had not. Lists 14 references. (YP)
Factors that determine the evolution of high-growth businesses
Directory of Open Access Journals (Sweden)
Oriol Amat
2013-09-01
Full Text Available Objective: The study herein discusses research aimed at elucidating the factors that contribute to a business’ ability to maintain high growth. Design/Methodology/Perspective: The database from the Iberian Balance Sheet Analysis System (SABI, from its initials in Spanish was used to identify 250 industrial Catalonian businesses with high growth during 2004-2007. These companies participated in a survey on strategies and management practices; in 2013, they were re-analyzed to investigate the factors that contributed to continued growth for certain companies. Contributions: Through diverse statistical techniques, business policies related to quality, innovation, internationalization and finance were shown to influence business growth and sustainability over time. Limitations of the Research: This study focuses on industrial businesses at least ten years old in Catalonia; thus, the conclusions may differ in other geographic locations and economic sectors, as well as for smaller businesses. Practical Implications: Because growth is a measure of business success, identifying variables that contribute to high growth and its sustainability is helpful for businesses that seek to adopt effective policies. Social Implications: Generating employment is one of the primary contributions by high-growth businesses. For years with high unemployment, authorities may be interested in corporate policies that strengthen high-growth businesses. Originality/Added Value: High-growth businesses have been studied throughout the world, but this is the first study to investigate the evolution of businesses after a high-growth phase.
[Acupuncture clinical trials published in high impact factor journals].
Hu, Min; Liu, Jian-Ping; Wu, Xiao-Ke
2014-12-01
Acupuncture clinical trials are designed to provide reliable evidence of clinical efficacy, and SCI papers is one of the high-quality clinical efficacy of acupuncture research. To analyze these papers published in high impact factor journals on acupuncture clinical trials, we can study clinical trials from design to implementation, the efficacy of prevention and cure, combined with international standard practices to evaluate the effectiveness and safety of acupuncture. That is the core of acupuncture clinical trials, as well as a prerequisite for outstanding academic output. A scientific and complete acupuncture clinical trial should be topically novel, designed innovative, logically clear, linguistically refining, and the most important point lies in a great discovery and solving the pragmatic problem. All of these are critical points of papers to be published in high impact factor journal, and directly affect international evaluation and promotion of acupuncture.
The remnant group of local Lorentz transformations in f(T) theories
Ferraro, Rafael
2014-01-01
It is shown that the extended teleparallel gravitational theories, known as f(T) theories, inherit some \\emph{on shell} local Lorentz invariance associated with the tetrad field defining the spacetime structure. We discuss some enlightening examples, such as Minkowski spacetime and cosmological (FRW and Bianchi type I) manifolds. In the first case, we show that the absence of gravity reveals itself as an incapability in the selection of a preferred parallelization at a local level, due to the fact that the infinitesimal local Lorentz subgroup acts as a symmetry group of the frame characterizing Minkowski spacetime. Finite transformations are also discussed in these examples and, contrary to the common lore on the subject, we conclude that the set of tetrads responsible of the parallelization of these manifolds is quite vast and that the remnant group of local Lorentz transformations includes one and two dimensional abelian subgroups of the Lorentz group.
Low regularity solutions of the Chern-Simons-Higgs equations in the Lorentz gauge
Directory of Open Access Journals (Sweden)
Nikolaos Bournaveas
2009-09-01
Full Text Available We prove local well-posedness for the 2+1-dimensional Chern-Simons-Higgs equations in the Lorentz gauge with initial data of low regularity. Our result improves earlier results by Huh [10, 11].
Implications of Lorentz symmetry violation on a 5D supersymmetric model
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
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.
Directory of Open Access Journals (Sweden)
L.H.C. Borges
2016-05-01
Full Text Available We study the perturbative generation of higher-derivative Lorentz violating operators as quantum corrections to the photon effective action, originated from a specific Lorentz violation background, which has already been studied in connection with the physics of light pseudoscalars. We calculate the complete one loop effective action of the photon field through the proper-time method, using the zeta function regularization. This result can be used as a starting point to study possible effects of the Lorentz violating background we are considering in photon physics. As an example, we focus on the lowest order corrections and investigate whether they could influence the propagation of electromagnetic waves through the vacuum. We show, however, that no effects of the kind of Lorentz violation we consider can be detected in such a context, so that other aspects of photon physics have to be studied.
Charged Lifshitz black hole and probed Lorentz-violation fermions from holography
Directory of Open Access Journals (Sweden)
Cheng-Jian Luo
2017-06-01
Full Text Available 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.
Preliminary Design of a Pendulum Experiment for Searching for a Lorentz-Violation Signal
Shao, Cheng-Gang; Tan, Yu-Jie
2016-01-01
This work mainly presents a preliminary design for a pendulum experiment with both the source mass and the test mass in a striped pattern to amplify the Lorentz-violation signal, since the signal is sensitive to edge effects.
Wigner rotations, Bell states, and Lorentz invariance of entanglement and von Neumann entropy
Soo, C; Soo, Chopin; Lin, Cyrus C. Y.
2003-01-01
We compute, for massive particles, the explicit Wigner rotations of one-particle states for arbitrary Lorentz transformations; and the explicit Hermitian generators of the infinite-dimensional unitary representation. For a pair of spin 1/2 particles, Einstein-Podolsky-Rosen-Bell entangled states and their behaviour under the Lorentz group are analysed in the context of quantum field theory. Group theoretical considerations suggest a convenient definition of the Bell states which is slightly different from the conventional assignment. The behaviour of Bell states under arbitrary Lorentz transformations can then be described succinctly. Reduced density matrices applicable to identical particles are defined through Yang's prescription. The von Neumann entropy of each of the reduced density matrix is Lorentz invariant; and its relevance as a measure of entanglement is discussed, and illustrated with an explicit example. A regularization of the entropy in terms of generalized zeta functions is also suggested.
Two-pion exchange NN potential from Lorentz-invariant $\\chi$EFT
Energy Technology Data Exchange (ETDEWEB)
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.
Differential Geometry of Curves and Surfaces in Lorentz-Minkowski space
2008-01-01
We review part of the classical theory of curves and surfaces in $3$-dimensional Lorentz-Minkowski space. We focus in spacelike surfaces with constant mean curvature pointing the differences and similarities with the Euclidean space.
On Dirac-like Monopoles in a Lorentz- and CPT-violating Electrodynamics
Barraz, N M; Moura-Melo, W A; Helay"el-Neto, J A
2007-01-01
We study magnetic monopoles in a Lorentz- and CPT-odd electrodynamical framework in (3+1) dimensions. This is the standard Maxwell model extended by means of a Chern-Simons-like term, $b_\\mu\\tilde{F}^{\\mu\
Acousto-electrical speckle pattern in Lorentz force electrical impedance tomography
Grasland-Mongrain, Pol; Mari, Jean-Martial; Souchon, Remi; Catheline, Stefan; Chapelon, Jean-Yves; Lafon, Cyril; Cloutier, Guy
2015-01-01
Ultrasound speckle is a granular texture pattern appearing in ultrasound imaging. It can be used to distinguish tissues and identify pathologies. Lorentz force electrical impedance tomography is an ultrasound-based medical imaging technique of the tissue electrical conductivity. It is based on the application of an ultrasound wave in a medium placed in a magnetic field and on the measurement of the induced electric current due to Lorentz force. Similarly to ultrasound imaging, we hypothesized that a speckle could be observed with Lorentz force electrical impedance tomography imaging. In this study, we first assessed the theoretical similarity between the measured signals in Lorentz force electrical impedance tomography and in ultrasound imaging modalities. We then compared experimentally the signal measured in both methods using an acoustic and electrical impedance interface. Finally, a bovine muscle sample was imaged using the two methods. Similar speckle patterns were observed. This indicates the existence ...
The Lorentz Force and Energy-Momentum for Off-Shell Electromagnetism
Land, M C
2016-01-01
The kinematics of pre-Maxwell electrodynamics is examined and interpretations of these fields is found through an examination of the associated Lorentz force and the structure of the energy-momentum tensor.
Enhanced sensitivity to Lorentz invariance violations in short-range gravity experiments
Shao, Cheng-Gang; Tan, Yu-Jie; Luo, Jun; Yang, Shan-Qing; Tobar, Michael Edmund
2016-01-01
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.
Faessler, A; Holstein, Barry R; Lyubovitskij, V E; Nicmorus, D; Pumsa-ard, K; Faessler, Amand; Gutsche, Thomas; Holstein, Barry R.; Lyubovitskij, Valery E.; Nicmorus, Diana; Pumsa-ard, Kem
2006-01-01
We calculate magnetic moments of light baryons and N -> Delta gamma transition characteristics using a manifestly Lorentz covariant chiral quark approach for the study of baryons as bound states of constituent quarks dressed by a cloud of pseudoscalar mesons.
Electromagnetic properties of nucleons and hyperons in a Lorentz covariant quark model
Faessler, A; Holstein, B R; Lyubovitskij, V E; Nicmorus, D; Pumsa-ard, K; Faessler, Amand; Gutsche, Thomas; Holstein, Barry R.; Lyubovitskij, Valery E.; Nicmorus, Diana; Pumsa-ard, Kem
2006-01-01
We calculate magnetic moments of nucleons and hyperons and N -> Delta + gamma transition characteristics using a manifestly Lorentz covariant chiral quark approach for the study of baryons as bound states of constituent quarks dressed by a cloud of pseudoscalar mesons.
Testing Lorentz Invariance with Laser-Cooled Cesium Atomic Frequency Standards
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.