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Investigation of Single-Event Damages on Silicon Carbide (SiC) Power MOSFETs
http://inspirehep.net/record/1317578
IEEE Trans.Nucl.Sci. 61 (2014) 1924-1928<br /><br />by: Mizuta, E.<br /><strong>Abstract:</strong> <br />Radiation effects were demonstrably observed in silicon carbide power MOSFETs caused by heavy ion and proton irradiation. For higher LET ions, permanent damage (increase in both drain and gate leakage current) was observed similar to SiC Schottky Barrier diodes in our previous study. For lower LET ions, including protons, Single Event Burnouts (SEBs) were observed and there was no leakage current increase just before SEBs. The phenomenon is unique for SiC devices.Mizuta, E.Wed, 17 Sep 2014 17:00:59 GMThttp://inspirehep.net/record/13175782014Quadruple Well CMOS MAPS With Time-Invariant Processor Exposed to Ionizing Radiation and Neutrons
http://inspirehep.net/record/1317577
IEEE Trans.Nucl.Sci. 61 (2014) 1763-1771<br /><br />by: Ratti, Lodovico (INFN, Pavia) et al.<br /><br /><strong>Abstract:</strong> <br />Monolithic active pixel sensors featuring a time-invariant front-end channel have been fabricated in a quadruple well CMOS process in the frame of an R&D project aiming at developing low material budget, radiation hard detectors for tracking applications. MAPS prototypes have been exposed to integrated fluences up to 10^14 1 MeV neutron equivalent cm to test the device tolerance to bulk damage also for different values of the epitaxial layer resistivity. Moreover, samples of the same device have been irradiated with y-rays from a ^60Co source, reaching a final dose exceeding 10 Mrad, to study ionizing radiation effects. This work discusses the test results, obtained through different measurement techniques, and the mechanisms underlying performance degradation in irradiated quadruple well CMOS MAPS.Ratti, LodovicoWed, 17 Sep 2014 17:00:59 GMThttp://inspirehep.net/record/13175772014Unfolding JASON-2/ICARE-NG High-Energy Particles Measurements Using a Singular Value Decomposition Approach
http://inspirehep.net/record/1317576
IEEE Trans.Nucl.Sci. 61 (2014) 1687-1694<br /><br />by: Maget, V.<br /><strong>Abstract:</strong> <br />This paper presents an enhanced approach to extract as much as possible information from raw measurements of a given solid-state detector. Here we focus on the benefits of a singular value decomposition approach applied to the special case of the CNES-JASON 2 mission. It allows us to extract more information from the sensor than a more traditional technique. Refined differential fluxes instead of only coarse integral and differential ones are now obtained and to get an improved resolution for both protons (40-500 MeV) and electrons (825 keV to 8 MeV). Finally, thanks to the combination of all the information embedded into the different response functions of the ICARE-NG instrument, we are now able to: 1) estimate the uncertainty of our measurements, and 2) automatically filter contamination from both proton and electron in restored fluxes channels.Maget, V.Wed, 17 Sep 2014 17:00:58 GMThttp://inspirehep.net/record/13175762014An SRAM Based Monitor for Mixed-Field Radiation Environments
http://inspirehep.net/record/1317575
IEEE Trans.Nucl.Sci. 61 (2014) 1663-1670<br /><br />by: Tsiligiannis, G.<br /><strong>Abstract:</strong> <br />CERN hosts a large number of electronic devices and equipment, functioning over its different particle accelerators. In certain areas, they operate in harsh radiation environments. In order to assure their proper functionality, the equipment or some of their sensitive components undergo several tests in experimental test areas representative of the LHC radiation fields, while specialized monitors constantly record the respective radiation levels. The purpose of this study is to evaluate the use of monitors using recent technology nodes (90 nm) in order to have a better estimation of the expected error rate of the devices. The H4IRRAD experimental test area has been specifically designed to reproduce the radiation field that is present within the LHC tunnel and shielded areas. It has been used to test our custom SRAM based monitors. The monitors have been exposed to a maximum dose and high energy hadron fluence of about 76 Gy and 1.3 × 10^11 cm^-2 respectively. The results show that the total ionizing dose (TID) effect does not impact the bit cross section of our devices. Moreover the Single Event occurrence is coherent to the beam intensity fluctuations, proving that these devices are appropriate for SEU monitoring under mixed particle fields.Tsiligiannis, G.Wed, 17 Sep 2014 17:00:57 GMThttp://inspirehep.net/record/13175752014Noise Pulses in Large Area Optical Modules
http://inspirehep.net/record/1317574
IEEE Trans.Nucl.Sci. 61 (2014) 2097-2104<br /><br />by: Leonora, E.<br /><strong>Abstract:</strong> <br />Large area photomultipliers are widely used in neutrino and astro-particle detectors to measure Cherenkov light in media like water or ice. The key element of these detectors are the so-called ”optical module”, which consists of a photodetector enclosed in a transparent pressure-resistant container to protect it and ensure good light transmission. Noise pulses at the anode of each photomultiplier strongly affect the performance of the detector. A large study was conducted on noise pulses of large area photomultipliers, considering time and charge distributions of dark pulses, pre-pulses, delayed pulses, and after pulses. The contribution to noise pulses due to the presence of the external glass vessels was also studied, even comparing two vessels of different brands.Leonora, E.Wed, 17 Sep 2014 17:00:39 GMThttp://inspirehep.net/record/13175742014A Custom Online Ultrasonic Gas Mixture Analyzer With Simultaneous Flowmetry, Developed for the Upgraded Evaporative Cooling System of the ATLAS Silicon Tracker
http://inspirehep.net/record/1317573
IEEE Trans.Nucl.Sci. 61 (2014) 2059-2065<br /><br />by: Bates, R. (Glasgow U.) et al.<br /><br /><strong>Abstract:</strong> <br />We describe a combined ultrasonic instrument for continuous gas flow measurement and simultaneous real-time binary gas mixture analysis. In the instrument, sound bursts are transmitted in opposite directions, which may be aligned with the gas flow path or at an angle to it, the latter configuration being the best adapted to high flow rates. The combined flow measurement and mixture analysis algorithm exploits the phenomenon whereby the sound velocity in a binary gas mixture at known temperature and pressure is a unique function of the molar concentration of the two components. The instrument is central to a possible upgrade to the present ATLAS silicon tracker cooling system in which octafluoropropane (C F ) evaporative cooling fluid would be replaced by a blend containing up to 25% hexafluoroethane (C_2F_6). The instrument has been developed in two geometries following computational fluid dynamics studies of various mechanical layouts. An instrument with 45 crossing angle has been installed for commissioning in the ATLAS silicon tracker cooling system. It can be used in gas flows up to 20 000 l.min^-1 and has demonstrated a flow resolution of 2.3% of full scale for linear flow velocities up to 10 m.s in preliminary studies with air. Other instruments are currently used to detect low levels of C_2F_8 vapor leaking into the N_2 environmental gas surrounding the ATLAS silicon tracker. A long-duration continuous study of more than a year has demonstrated a sensitivity to mixture variation of better than 5.10^-5.Bates, R.Wed, 17 Sep 2014 17:00:38 GMThttp://inspirehep.net/record/13175732014Characterization of New Hexagonal Large Area MPPCs
http://inspirehep.net/record/1317572
IEEE Trans.Nucl.Sci. 61 (2014) 1474-1482<br /><br />by: Boccone, V.<br /><strong>Abstract:</strong> <br />Photomultipliers (PMTs) are the standard detector for construction of the current generation of imaging Atmospheric Cherenkov Telescopes (IACTs). Despite impressive improvements in Quantum Efficiency (QE) and reliability in the last years, these devices suffer from the limitation of being unable to operate in the partially illuminated sky (during full or partial moon periods) as the excess light leads to a significant increase in the rate of ageing of the devices themselves and consequently limit the camera life. Large area Multi-Pixel Photon Counters (MPPCs) - also known as Geiger-mode avalanche photodiodes (G-APDs) or Silicon Photomultipliers (SiPMs) - are a viable alternative and are commercially available from different producers in various types and dimensions. The maturity of this technology for application to Cherenkov Astronomy has already been demonstrated by the FACT telescope. The Small Size Telescopes (SSTs) of Cherenkov Telescope Array (CTA) observatory foresee the usage of MPPCs. One of the designs for a 4 m-diameter dish Davies-Cotton telescope engages custom designed large-area hexagonal MPPCs. This is the first time that an hexagonal device with area of 95 mm^2 divided in 4 channels is made available. These photosensors, coupled with open non imaging light concentrators with a 24 degrees cut-off angle, offer a performing alternative to standard PMTs. In this paper we show the results of their characterization together with the comparison with other commercially available devices such as the Hamamatsu S10985-050C (2×2 array of 3 mm ×3 mm MPPCs) and the SensLμSB30035-X13-E15.Boccone, V.Wed, 17 Sep 2014 17:00:29 GMThttp://inspirehep.net/record/13175722014Development of a Fast Timing Counter with a Monolithic MPPC Array
http://inspirehep.net/record/1317571
IEEE Trans.Nucl.Sci. 61 (2014) 1278-1283<br /><br />by: Nishizawa, T.<br /><strong>Abstract:</strong> <br />We developed a timing counter with a monolithic array of multi-pixel photon counters (MPPCs) coupled to a 10 ×12.6 ×24 mm^3 plastic scintillator. A signal of the MPPC was processed and its fast components were amplified by a developed readout circuit to improve the timing. The performances of the counter were evaluated by electrons with energies of 855 MeV. A set of the MPPC based scintillation counter and a PMT based reference counter achieved the TOF resolution less than 80 ps ( σ). The gain was almost constant up to the count rate of 170 kHz.Nishizawa, T.Wed, 17 Sep 2014 17:00:29 GMThttp://inspirehep.net/record/13175712014A Self-Triggered Column-Level ADC for CMOS Pixel Sensors in High Energy Physics
http://inspirehep.net/record/1317570
IEEE Trans.Nucl.Sci. 61 (2014) 1269-1277<br /><br />by: Zhang, Liang (Shandong U.) et al.<br /><br /><strong>Abstract:</strong> <br />CMOS pixel sensors (CPS) for the future linear collider vertex detector (VXD) have strict requirements on their analog readout electronics, particularly on the analog-to-digital converter (ADC). This paper presents a low-power and small-area 4-bit column-level ADC for the CMOS pixel sensor, foreseen to equip the outer layers of the VXD. The ADC employs a self-triggered timing and completes the conversion by performing a multi-bit/step approximation. Accounting the fact that in the outer layers, the hit density is in the order of a few per thousand, this ADC is designed to operate in two modes: active mode and inactive mode. The average energy and total capacitance are significantly reduced by a power-gating control and a switching network, respectively. The ADC is fabricated in a 0.35 μm CMOS process with a pixel pitch of 35 μm. It is implemented with 48 columns in a sensor prototype. Each column ADC occupies an area of 35×545 μm^2. The measured temporal noise and fixed pattern noise (FPN) are 0.94 and 0.30 mV, respectively. The power consumption, at a 3-V supply and 6.25-MS/s sampling rate, equals to 486 μW in its inactive mode, which is by far the most frequent. This value rises to 714 μW in case of the active mode. These computations indicate an average power consumption of each column in the order of 487 μW, assuming a typical occupancy of ~ 0.5% in the whole sensor. Its DNL and INL are 0.49/-0.28 and 0.29/-0.20 least significant bit, respectively.Zhang, LiangWed, 17 Sep 2014 17:00:28 GMThttp://inspirehep.net/record/13175702014Investigation of molecular states with charm and beauty hadrons
http://inspirehep.net/record/1317172
<br />by: Xiao, Chu-Wen (Valencia U.)<br />Xiao, Chu-WenTue, 16 Sep 2014 22:29:50 GMThttp://inspirehep.net/record/1317172The Pulsating sdB+M Eclipsing System NY Virginis and its Circumbinary Planets
http://inspirehep.net/record/1317749
astro-ph.SRarXiv:1409.4907<br /><br />by: Lee, Jae Woo<br /><strong>Abstract:</strong> <br />We searched for circumbinary planets orbiting NY Vir in historical eclipse times including our long-term CCD data. Sixty-eight times of minimum light with accuracies better than 10 s were used for the ephemeris computations. The best fit to those timings indicated that the orbital period of NY Vir has varied due to a combination of two sinusoids with periods of $P_3$=8.2 yr and $P_4$=27.0 yr and semi-amplitudes of $K_3$=6.9 s and $K_4$=27.3 s, respectively. The periodic variations most likely arise from a pair of light-time effects due to the presence of third and fourth bodies that are gravitationally bound to the eclipsing pair. We have derived the orbital parameters and the minimum masses, $M_3 \sin i_3$ = 2.8 M$\rm_{Jup}$ and $M_4 \sin i_4$ = 4.5 M$\rm_{Jup}$, of both objects. A dynamical analysis suggests that the outer companion is less likely to orbit the binary on a circular orbit. Instead we show that future timing data might push its eccentricity to moderate values for which the system exhibits long-term stability. The results demonstrate that NY Vir is probably a star-planet system, which consists of a very close binary star and two giant planets. The period ratio $P_{3}/P_{4}$ suggests that a long-term gravitational interaction between them would result in capture into a nearly 3:10 mean motion resonance. When the presence of the circumbinary planets is verified and understood more comprehensively, the formation and evolution of this planetary system should be advanced greatly.Lee, Jae WooTue, 16 Sep 2014 22:00:00 GMThttp://inspirehep.net/record/1317749Search for charged Higgs bosons decaying via $H^{\pm} \rightarrow \tau^{\pm} \nu$ in hadronic final states using $pp$ collision data at $\sqrt{s} = 8~\mbox{TeV}$ with the ATLAS detector
http://inspirehep.net/record/1317731
ATLAS-CONF-2014-050<br />ATLAS-COM-CONF-2014-071<br /><br />by: The ATLAS collaboration<br /><strong>Abstract:</strong> <br />The results of a search for charged Higgs bosons decaying to a tau lepton and a neutrino, $H^{\pm} \to \tau^{\pm} \nu$, are presented. The analysis is based on 19.5 fb$^{-1}$ of proton-proton collision data at $\sqrt{s}=8$ TeV collected by the ATLAS experiment at the Large Hadron Collider. Charged Higgs bosons are searched for in events consistent with top-quark pair production or in associated production with a top quark. The final state is characterised by the presence of a hadronic $\tau$ decay, missing transverse momentum, $b$-jets, a hadronically decaying $W$ boson, and the absence of any electrons or muons. The data are consistent with the expected background from Standard Model processes. This leads to 95 % confidence level upper limits on the branching ratio of top-quark decays to a $b$ quark and a charged Higgs boson times branching ratio, $ {\cal B}(t\rightarrow bH^\pm) \times {\cal B}(H^\pm\rightarrow \tau^{\pm}\nu) $, between 0.23 % and 1.3 % for charged Higgs boson masses in the range $80-160$ GeV. This also leads to 95 % confidence level upper limits on the production cross section times branching ratio, $\sigma(pp \to tH^{\pm} + X) \times {\cal B}(H^{\pm} \to \tau^{\pm} \nu)$, between 0.0045 pb and 0.76 pb, for charged Higgs boson masses ranging from 180 GeV to 1000 GeV.The ATLAS collaborationTue, 16 Sep 2014 22:00:00 GMThttp://inspirehep.net/record/1317731Compressive Earth Observatory: An Insight from AIRS/AMSU Retrievals
http://inspirehep.net/record/1317694
physics.data-anarXiv:1409.5068<br /><br />by: Ebtehaj, Ardeshir Mohammad<br /><strong>Abstract:</strong> <br />We demonstrate that the global fields of temperature, humidity and geopotential heights admit a nearly sparse representation in the wavelet domain, offering a viable path forward to explore new paradigms of sparsity-promoting assimilation and compressive retrieval of spaceborne earth observations. We illustrate this idea using retrieval products of the Atmospheric Infrared Sounder (AIRS) and Advanced Microwave Sounding Unit (AMSU) on board the Aqua satellite. The results reveal that the sparsity of the fields of temperature and geopotential height is relatively pressure-independent while atmospheric humidity fields are typically less sparse at higher pressures. Using the sparsity prior, we provide evidence that the global variability of these land-atmospheric states can be accurately estimated from space in a compressed form, using a small set of randomly chosen measurements/retrievals.Ebtehaj, Ardeshir MohammadTue, 16 Sep 2014 22:00:00 GMThttp://inspirehep.net/record/1317694Deformed shell model results for neutrinoless double beta decay of nuclei in A=60-90 region
http://inspirehep.net/record/1317693
nucl-tharXiv:1409.4929<br /><br />by: Sahu, R.<br /><strong>Abstract:</strong> <br />Nuclear transition matrix elements (NTME) for the neutrinoless double beta decay of $^{70}$Zn, $^{80}$Se and $^{82}$Se nuclei are calculated within the framework of the deformed shell model based on Hartree-Fock states. For $^{70}$Zn, jj44b interaction in $^{2}p_{3/2}$, $^{1}f_{5/2}$, $^{2}p_{1/2}$ and $^{1}g_{9/2}$ space with $^{56}$Ni as the core is employed. However, for $^{80}$Se and $^{82}$Se nuclei, a modified Kuo interaction with the above core and model space are employed. Most of our calculations in this region were performed with this effective interaction. However, jj44b interaction has been found to be better for $^{70}$Zn. After ensuring that DSM gives good description of the spectroscopic properties of low-lying levels in these three nuclei considered, the NTME are calculated. The deduced half-lives with these NTME, assuming neutrino mass is 1 eV, are $9.6 \times 10^{25}$yr, $1.9 \times 10^{27}$yr and $1.95 \times 10^{24}$yr for $^{70}$Zn, $^{80}$Se and $^{82}$Se, respectively.Sahu, R.Tue, 16 Sep 2014 22:00:00 GMThttp://inspirehep.net/record/1317693Fission induced by nucleons at intermediate energies
http://inspirehep.net/record/1317692
nucl-tharXiv:1409.4885<br /><br />by: Meo, Sergio Lo<br /><strong>Abstract:</strong> <br />Monte Carlo calculations of fission of actinides and pre-actinides induced by protons and neutrons in the energy range from 100 MeV to 1 GeV are carried out by means of a recent version of the Li\`ege Intranuclear Cascade Model, INCL++, coupled with two different evaporation-fission codes, GEMINI++ and ABLA07. In order to reproduce experimental fission cross sections, model parameters are usually adjusted on available (p,f) cross sections and used to predict (n,f) cross sections for the same isotopes.Meo, Sergio LoTue, 16 Sep 2014 22:00:00 GMThttp://inspirehep.net/record/1317692Proton-neutron pairing vibrations in N=Z nuclei: Precursory soft mode of isoscalar pairing condensation
http://inspirehep.net/record/1317689
nucl-tharXiv:1409.4884<br /><br />by: Yoshida, Kenichi<br /><strong>Abstract:</strong> <br />L=0 proton-neutron ($pn$) pair-addition and pair-removal strengths in $^{40}$Ca and $^{56}$Ni are investigated by means of the $pn$ particle-particle random-phase approximation employing a Skyrme energy-density functional. It is found that the collectivity of the lowest $J^\pi = 1^+$ state in the adjacent odd-odd nuclei becomes stronger as the strength of the isoscalar (T=0) pairing interaction increases. The results suggest the emergence of the T=0 $pn$-pairing vibrational mode as a possible critical phenomenon toward the T=0 pairing condensation.Yoshida, KenichiTue, 16 Sep 2014 22:00:00 GMThttp://inspirehep.net/record/1317689Quantum phase transitions in the noncommutative Dirac Oscillator
http://inspirehep.net/record/1317687
hep-tharXiv:1409.5077<br /><br />by: Panella, O.<br /><strong>Abstract:</strong> <br />We study the (2+1) dimensional Dirac oscillator in a homogeneous magnetic field in the non-commutative plane. It is shown that the effect of non-commutativity is twofold: $i$) momentum non commuting coordinates simply shift the critical value ($B_{\text{cr}}$) of the magnetic field at which the well known left-right chiral quantum phase transition takes place (in the commuting phase); $ii$) non-commutativity in the space coordinates induces a new critical value of the magnetic field, $B_{\text{cr}}^*$, where there is a second quantum phase transition (right-left), --this critical point disappears in the commutative limit--. The change in chirality associated with the magnitude of the magnetic field is examined in detail for both critical points. The phase transitions are described in terms of the magnetisation of the system. Possible applications to the physics of silicene and graphene are briefly discussed.Panella, O.Tue, 16 Sep 2014 22:00:00 GMThttp://inspirehep.net/record/1317687Sum rules and spectral density flow in QCD and in superconformal theories
http://inspirehep.net/record/1317686
hep-tharXiv:1409.5075<br /><br />by: Costantini, Antonio<br /><strong>Abstract:</strong> <br />We discuss the signature of the anomalous breaking of the superconformal symmetry in $\mathcal{N}=1$ super Yang Mills theory and its manifestation in the form of anomaly poles. Moreover, we describe the massive deformations of the $\mathcal{N}=1$ theory and the spectral densities of the corresponding anomaly form factors. These are characterized by spectral densities which flow with the mass deformation and turn the continuum contributions from the two-particle cuts of the intermediate states into poles, with a single sum rule satisfied by each component. The poles can be interpreted as signaling the exchange of a composite axion/dilaton/dilatino (ADD) multiplet in the effective Lagrangian. We conclude that global anomalous currents characterized by a single flow in the perturbative picture always predict the existence of composite interpolating fields.Costantini, AntonioTue, 16 Sep 2014 22:00:00 GMThttp://inspirehep.net/record/1317686Gauge Field Emergence from Kalb-Ramond Localization
http://inspirehep.net/record/1317685
hep-tharXiv:1409.5042<br /><br />by: Alencar, G.<br /><strong>Abstract:</strong> <br />A new mechanism, valid for any smooth version of the Randall-Sundrum model, of getting localized massless vector field on the brane is described here. This is obtained by dimensional reduction of a five dimension massive two form, or Kalb-Ramond field, giving a Kalb-Ramond and an emergent vector field in four dimensions. In order to reach this we propose a Yukawa coupling with the Ricci scalar and fix the coupling constant such that we get the components of fields localized. This solution is obtained by decomposing the fields in transversal and longitudinal parts and showing that this provides decoupled equations of motion for the a transverse vector and KR fields in four dimensions. To this end we prove some identities satisfied by the transverse components of the fields. This proof is valid for any smooth version of the RS model. With this we fix the coupling constant in a way that we obtain a localized zero mode for both components on the brane. Then we generalize all the above results to the massive $p-$form field. We show that in general we can not obtain effective $p$ and $(p-1)-$forms localized on the brane and we must choose one of them to localize. Therefore, for example, we can not have a vector and a scalar field localized by dimensional reducion of the five dimensional vector field. In fact we find the expression $p=(d-1)/2$ wich determines, in function of $D$, what forms will gives rise to both fields localized. For $D=5$ as expected, this is valid only for the KR field.Alencar, G.Tue, 16 Sep 2014 22:00:00 GMThttp://inspirehep.net/record/1317685A Note on Instanton Effects in ABJM Theory
http://inspirehep.net/record/1317684
hep-tharXiv:1409.4967<br />USTC-ICTS-14-17<br /><br />by: Wang, Xian-fu<br /><strong>Abstract:</strong> <br />We consider the quantum spectral problem appearing the Fermi gas formulation of the ABJM (Aharony-Bergman-Jafferis-Maldacena) matrix model. This is known to related to the refined topological string on local P^1*P^1 Calabi-Yau geometry. In the ABJM setting the problem is formulated by an integral equation, and is somewhat different from the one formulated directly in terms of the Calabi-Yau geometry and studied in our earlier paper. We use the similar method in our earlier paper to determine the non-perturbative contributions to the quantum phase volume in the ABJM case from the Bohr-Sommerfeld quantization condition. As in our earlier paper, the non-perturbative contributions contain higher order smooth corrections beyond those required by singularity cancellations with the perturbative contributions proposed by Kallen and Marino. Our results imply possible new contributions to the grand potential of the ABJM matrix model.Wang, Xian-fuTue, 16 Sep 2014 22:00:00 GMThttp://inspirehep.net/record/1317684Holographic quantum phase transitions and interacting bulk scalars
http://inspirehep.net/record/1317683
hep-tharXiv:1409.4959<br /><br />by: Chaturvedi, Pankaj<br /><strong>Abstract:</strong> <br />We consider a system of two massive, mutually interacting probe real scalar fields, in zero temperature holographic backgrounds. The system does not have any continuous symmetry. We have shown that, for suitable parameter range, as we turn on the source for one scalar field, the system may go through a second order quantum critical phase transition across which the second scalar field forms a condensate. We have looked at the resulting phase diagram and numerically computed the condensate. We investigate our system in two different backgrounds: $AdS_4$ and $AdS$ soliton, and got similar phase structure.Chaturvedi, PankajTue, 16 Sep 2014 22:00:00 GMThttp://inspirehep.net/record/1317683QED as the tensionless limit of the spinning string with contact interaction
http://inspirehep.net/record/1317682
hep-tharXiv:1409.4948<br />DCPT-14-39<br /><br />by: Edwards, James P.<br /><strong>Abstract:</strong> <br />We outline how QED with spinor matter can be described by the tensionless limit of spinning strings with contact interactions. The strings represent electric lines of force with charges at their ends. The contact interaction is constructed from a delta-function on the world-sheet which, although off-shell, decouples from the world-sheet metric. Integrating out the string degrees of freedom with fixed boundary generates the super-Wilson loop that couples spinor matter to electromagnetism in the world-line formalism. World-sheet and world-line, but not spacetime, supersymmetry underpin the model.Edwards, James P.Tue, 16 Sep 2014 22:00:00 GMThttp://inspirehep.net/record/1317682Topologically distinct critical theories emerging from the bulk entanglement spectrum of integer quantum Hall states on a lattice
http://inspirehep.net/record/1317681
cond-mat.str-elarXiv:1409.4916<br /><br />by: Zhu, Qiong<br /><strong>Abstract:</strong> <br />The critical theories for the topological phase transitions of integer quantum Hall states to a trivial insulating state with the same symmetry can be obtained by calculating the ground state entanglement spectrum under a symmetric checkerboard bipartition. In contrast to the gapless edge excitations under the left-right bipartition, a quantum network with bulk gapless excitations naturally emerges at the Brillouin zone center without fine tuning. On a large finite lattice, the resulting critical theory for the $\nu =1$ state is the (2+1) dimensional relativistic quantum field theory characterized by a \textit{single} Dirac cone spectrum and a pair of \textit{fractionalized} zero-energy states, while for the $\nu =2$ state the critical theory exhibits a parabolic spectrum and no sign of fractionalization in the zero-energy states. A triangular correspondence is established among the bulk topological theory, gapless edge theory, and the critical theory via the ground state entanglement spectrum.Zhu, QiongTue, 16 Sep 2014 22:00:00 GMThttp://inspirehep.net/record/1317681Generalized Gravitational Entropy of Interacting Scalar Field and Maxwell Field
http://inspirehep.net/record/1317680
hep-tharXiv:1409.4893<br /><br />by: Huang, Wung-Hong<br /><strong>Abstract:</strong> <br />The generalized gravitational entropy proposed by Lewkowycz and Maldacena in recent is extended to the interacting real scalar field and Maxwell field system. Using the BTZ geometry we first investigate the case of free real scalar field and then show a possible way to calculate the entropy of the interacting scalar field. Next, we investigate the Maxwell field system. We exactly solve the wave equation and calculate the analytic value of the generalized gravitational entropy. We also use the Einstein equation to find the effect of backreaction of the Maxwell field on the spacetime. The associated modified area law is consistent with the generalized gravitational entropy. Our investigations have not found the unexpected anomalous surface term.Huang, Wung-HongTue, 16 Sep 2014 22:00:00 GMThttp://inspirehep.net/record/1317680Coupling hydrodynamics to nonequilibrium degrees of freedom in strongly interacting quark-gluon plasma
http://inspirehep.net/record/1317676
hep-tharXiv:1409.5087<br /><br />by: Heller, Michal P.<br /><strong>Abstract:</strong> <br />Relativistic hydrodynamics simulations of quark-gluon plasma play a pivotal role in our understanding of heavy ion collisions at RHIC and LHC. They are based on a phenomenological description due to Mueller, Israel, Stewart (MIS) and others, which incorporates viscous effects and ensures a well-posed initial value problem. Focusing on the case of conformal plasma we propose a generalization which includes, in addition, the dynamics of the least damped far-from-equilibrium degree of freedom found in strongly coupled plasmas through the AdS/CFT correspondence. We formulate new evolution equations for general flows and then test them in the case of N=4 super Yang-Mills plasma by comparing their solutions alongside solutions of MIS theory with numerical computations of isotropization and boost-invariant flow based on holography. In these tests the new equations reproduce the results of MIS theory when initialized close to the hydrodynamic stage of evolution, but give a more accurate description of the dynamics when initial conditions are set in the pre-equilibrium regime.Heller, Michal P.Tue, 16 Sep 2014 22:00:00 GMThttp://inspirehep.net/record/1317676