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Based on the idea and the provided source code of Andrej Karpathy (arxiv-sanity)
Sensitivity and discovery potential of the proposed nEXO experiment to neutrinoless double beta decay (1710.05075)
nEXO Collaboration: J.B. Albert, G. Anton, I.J. Arnquist, I. Badhrees, P.S. Barbeau, D. Beck, V. Belov, F. Bourque, J.P. Brodsky, E. Brown, T. Brunner, A. Burenkov, G.F. Cao, L. Cao, W.R. Cen, C. Chambers, S.A. Charlebois, M. Chiu, B. Cleveland, M. Coon, M. Côté, A. Craycraft, W. Cree, J. Dalmasson, T. Daniels, S.J. Daugherty, J. Daughhetee, R. DeVoe, S. Delaquis, A. Der Mesrobian-Kabakian, T. Didberidze, J. Dilling, Y.Y. Ding, M.J. Dolinski, A. Dragone, L. Fabris, W. Fairbank, J. Farine, S. Feyzbakhsh, R. Fontaine, D. Fudenberg, G. Giacomini, R. Gornea, K. Graham, G. Gratta, E.V. Hansen, D. Harris, M. Hasan, M. Heffner, E.W. Hoppe, J. Hößl, A. House, P. Hufschmidt, M. Hughes, Y. Ito, A. Iverson, A. Jamil, M.J. Jewell, X.S. Jiang, T.N. Johnson, S. Johnston, A. Karelin, L.J. Kaufman, R. Killick, T. Koffas, S. Kravitz, R. Krücken, A. Kuchenkov, K.S. Kumar, Y. Lan, D.S. Leonard, G. Li, S. Li, Z. Li, C. Licciardi, Y.H. Lin, R. MacLellan, T. Michel, B. Mong, D.C. Moore, K. Murray, R.J. Newby, Z. Ning, O. Njoya, F. Nolet, K. Odgers, A. Odian, M. Oriunno, J.L. Orrell, G.S. Ortega, I. Ostrovskiy, C.T. Overman, S. Parent, A. Piepke, A. Pocar, J.-F. Pratte, D. Qiu, V. Radeka, E. Raguzin, T. Rao, S. Rescia, F. Retière, A. Robinson, T. Rossignol, P.C. Rowson, N. Roy, R. Saldanha, S. Sangiorgio, S. Schmidt, J. Schneider, A. Schubert, D. Sinclair, K. Skarpaas VIII, A.K. Soma, G. St-Hilaire, V. Stekhanov, T. Stiegler, X.L. Sun, M. Tarka, J. Todd, T. Tolba, R. Tsang, T. Tsang, F. Vachon, V. Veeraraghavan, G. Visser, P. Vogel, J.-L. Vuilleumier, M. Wagenpfeil, Q. Wang, M. Weber, W. Wei, L.J. Wen, U. Wichoski, G. Wrede, S.X. Wu, W.H. Wu, L. Yang, Y.-R. Yen, O. Zeldovich, J. Zettlemoyer, X. Zhang, J. Zhao, Y. Zhou, T. Ziegler
Oct. 19, 2018 nucl-ex, physics.ins-det
The next-generation Enriched Xenon Observatory (nEXO) is a proposed experiment to search for neutrinoless double beta ($0\nu\beta\beta$) decay in $^{136}$Xe with a target half-life sensitivity of approximately $10^{28}$ years using $5\times10^3$ kg of isotopically enriched liquid-xenon in a time projection chamber. This improvement of two orders of magnitude in sensitivity over current limits is obtained by a significant increase of the $^{136}$Xe mass, the monolithic and homogeneous configuration of the active medium, and the multi-parameter measurements of the interactions enabled by the time projection chamber. The detector concept and anticipated performance are presented based upon demonstrated realizable background rates.
Limits on light WIMPs with a 1 kg-scale germanium detector at 160 eVee physics threshold at the China Jinping Underground Laboratory (1710.06650)
L.T. Yang, H.B. Li, Q. Yue, K.J. Kang, J.P. Cheng, Y.J. Li, H.T. Wong, M. Aǧartioǧlu, H.P. An, J.P. Chang, J.H. Chen, Y.H. Chen, Z. Deng, Q. Du, H. Gong, L. He, J.W. Hu, Q.D. Hu, H.X. Huang, L.P. Jia, H. Jiang, H. Li, J.M. Li, J. Li, X. Li, X.Q. Li, Y.L. Li, F.K. Lin, S.T. Lin, S.K. Liu, Z.Z. Liu, H. Ma, J.L. Ma, H. Pan, J. Ren, X.C. Ruan, B. Sevda, V. Sharma, M.B. Shen, L. Singh, M.K. Singh, C.J. Tang, W.Y. Tang, Y. Tian, J.M. Wang, L. Wang, Q. Wang, Y. Wang, S.Y. Wu, Y.C. Wu, H.Y. Xing, Y. Xu, T. Xue, S.W. Yang, N. Yi, C.X. Yu, H.J. Yu, J.F. Yue, X.H. Zeng, M. Zeng, Z. Zeng, Y.H. Zhang, M.G. Zhao, W. Zhao, J.F. Zhou, Z.Y. Zhou, J.J. Zhu, Z.H. Zhu
June 26, 2018 hep-ex, physics.ins-det
We report results of a search for light weakly interacting massive particle (WIMP) dark matter from the CDEX-1 experiment at the China Jinping Underground Laboratory (CJPL). Constraints on WIMP-nucleon spin-independent (SI) and spin-dependent (SD) couplings are derived with a physics threshold of 160 eVee, from an exposure of 737.1 kg-days. The SI and SD limits extend the lower reach of light WIMPs to 2 GeV and improve over our earlier bounds at WIMP mass less than 6 GeV.
Bose-Einstein Condensation of Quasi-Particles by Rapid Cooling (1612.07305)
M. Schneider, T. Brächer, V. Lauer, P. Pirro, D. A. Bozhko, A. A. Serga, H. Yu. Musiienko-Shmarova, B. Heinz, Q. Wang, T. Meyer, F. Heussner, S. Keller, E. Th. Papaioannou, B. Lägel, T. Löber, V. S. Tiberkevich, A. N. Slavin, C. Dubs, B. Hillebrands, A.V. Chumak
May 17, 2018 cond-mat.other, cond-mat.mes-hall
The fundamental phenomenon of Bose-Einstein Condensation (BEC) has been observed in different systems of real and quasi-particles. The condensation of real particles is achieved through a major reduction in temperature while for quasi-particles a mechanism of external injection of bosons by irradiation is required. Here, we present a novel and universal approach to enable BEC of quasi-particles and to corroborate it experimentally by using magnons as the Bose-particle model system. The critical point to this approach is the introduction of a disequilibrium of magnons with the phonon bath. After heating to an elevated temperature, a sudden decrease in the temperature of the phonons, which is approximately instant on the time scales of the magnon system, results in a large excess of incoherent magnons. The consequent spectral redistribution of these magnons triggers the Bose-Einstein condensation.
Mass Measurements of Neutron-Deficient Y, Zr, and Nb Isotopes and Their Impact on $rp$ and $\nu p$ Nucleosynthesis Processes (1804.02309)
Y. M. Xing, K. A. Li, Y. H. Zhang, X. H. Zhou, M. Wang, Yu. A. Litvinov, K. Blaum, S. Wanajo, S. Kubono, G. Martínez-Pinedo, A. Sieverding, R. J. Chen, P. Shuai, C. Y. Fu, X. L. Yan, W. J. Huang, X. Xu, X. D. Tang, H. S. Xu, T. Bao, X. C. Chen, B. S. Gao, J. J. He, Y. H. Lam, H. F. Li, J. H. Liu, X. W. Ma, R. S. Mao, M. Si, M. Z. Sun, X. L. Tu, Q. Wang, J. C. Yang, Y. J. Yuan, Q. Zeng, P. Zhang, X. Zhou, W. L. Zhan, S. Litvinov, G. Audi, T. Uesaka, Y. Yamaguchi, T. Yamaguchi, A. Ozawa, C. Fröhlich, T. Rauscher, F.-K. Thielemann, B. H. Sun, Y. Sun, A. C. Dai, F. R. Xu
April 6, 2018 nucl-ex, astro-ph.SR
Using isochronous mass spectrometry at the experimental storage ring CSRe in Lanzhou, the masses of $^{82}$Zr and $^{84}$Nb were measured for the first time with an uncertainty of $\sim 10$ keV, and the masses of $^{79}$Y, $^{81}$Zr, and $^{83}$Nb were re-determined with a higher precision. %The latter differ significantly from their literature values. The latter are significantly less bound than their literature values. Our new and accurate masses remove the irregularities of the mass surface in this region of the nuclear chart. Our results do not support the predicted island of pronounced low $\alpha$ separation energies for neutron-deficient Mo and Tc isotopes, making the formation of Zr-Nb cycle in the $rp$-process unlikely. The new proton separation energy of $^{83}$Nb was determined to be 490(400)~keV smaller than that in the Atomic Mass Evaluation 2012. This partly removes the overproduction of the $p$-nucleus $^{84}$Sr relative to the neutron-deficient molybdenum isotopes in the previous $\nu p$-process simulations.
Study on cosmogenic activation in germanium detectors for future tonne-scale CDEX experiment (1802.09327)
J. L. Ma, Q. Yue, S. T. Lin, H. T. Wong, J. W. Hu, L. P. Jia, H. Jiang, J. Li, S. K. Liu, Z. Z. Liu, H. Ma, W. Y. Tang, Y. Tian, L. Wang, Q. Wang, L. T. Yang, Z. Zeng
Feb. 26, 2018 hep-ex, physics.ins-det, astro-ph.IM
A study on cosmogenic activation in germanium was carried out to evaluate the cosmogenic background level of natural and $^{70}$Ge depleted germanium detectors. The production rates of long-lived radionuclides were calculated with Geant4 and CRY, and the results were validated by comparing the simulated and experimental spectra of CDEX-1B detector. Based on the validated codes, a prediction was made on the cosmogenic background level for further tonne-scale CDEX experiment. The suppression of cosmogenic background level could be achieved by underground germanium crystal growth and high purity germanium detector fabrication to reach the sensitivity requirement in direct detection of dark matter. With low cosmogenic background, new physics channels would also be open such as solar neutrino research and neutrinoless double beta decay experiments, and corresponding simulations and evaluations were also carried out.
Limits on light WIMPs from the first 102.8 kg-days data of the CDEX-10 experiment (1802.09016)
H. Jiang, L. P. Jia, Q. Yue, K. J. Kang, J. P. Cheng, Y. J. Li, H. T. Wong, M. Agartioglu, H. P. An, J. P. Chang, J. H. Chen, Y. H. Chen, Z. Deng, Q. Du, H. Gong, L. He, J. W. Hu, Q. D. Hu, H. X. Huang, H. B. Li, H. Li, J. M. Li, J. Li, X. Li, X. Q. Li, Y. L. Li, B. Liao, F. K. Lin, S. T. Lin, S. K. Liu, Y. D. Liu, Y. Y. Liu, Z. Z. Liu, H. Ma, J. L. Ma, H. Pan, J. Ren, X. C. Ruan, B. Sevda, V. Sharma, M. B. Shen, L. Singh, M. K. Singh, T. X. Sun, C. J. Tang, W. Y. Tang, Y. Tian, G. F. Wang, J. M. Wang, L. Wang, Q. Wang, Y. Wang, S. Y. Wu, Y. C. Wu, H. Y. Xing, Y. Xu, T. Xue, L. T. Yang, S. W. Yang, N. Yi, C. X. Yu, H. J. Yu, J. F. Yue, X. H. Zeng, M. Zeng, Z. Zeng, F. S. Zhang, Y. H. Zhang, M. G. Zhao, J. F. Zhou, Z. Y. Zhou, J. J. Zhu, Z. H. Zhu
Feb. 25, 2018 hep-ex, physics.ins-det
We report the first results of light Weakly Interacting Massive Particles (WIMPs) search from the CDEX-10 experiment with a 10 kg germanium detector array immersed in liquid nitrogen at the China Jinping Underground Laboratory with an exposure of 102.8 kg-days. At an analysis threshold of 160 eVee, improved limits of 8 $\times 10^{-42}$ cm$^{2}$ and 3 $\times 10^{-36}$ cm$^{2}$ at 90% confidence level on spin-independent and spin-dependent WIMP-nucleon cross-sections, respectively, at a WIMP mass (m$_{\chi}$) of 5 GeV/$c^2$ are achieved. The lower reach of m$_{\chi}$ is extended to 2 GeV/$c^2$.
Characterization of an Ionization Readout Tile for nEXO (1710.05109)
nEXO Collaboration: M. Jewell, A. Schubert, W.R. Cen, J. Dalmasson, R. DeVoe, L. Fabris, G. Gratta, A. Jamil, G. Li, A. Odian, M. Patel, A. Pocar, D. Qiu, Q. Wang, L.J. Wen, J.B. Albert, G. Anton, I.J. Arnquist, I. Badhrees, P. Barbeau, D. Beck, V. Belov, F. Bourque, J. P. Brodsky, E. Brown, T. Brunner, A. Burenkov, G.F. Cao, L. Cao, C. Chambers, S.A. Charlebois, M. Chiu, B. Cleveland, M. Coon, A. Craycraft, W. Cree, M. Côté, T. Daniels, S.J. Daugherty, J. Daughhetee, S. Delaquis, A. Der Mesrobian-Kabakian, T. Didberidze, J. Dilling, Y.Y. Ding, M.J. Dolinski, A. Dragone, W. Fairbank, J. Farine, S. Feyzbakhsh, R. Fontaine, D. Fudenberg, G. Giacomini, R. Gornea, E.V. Hansen, D. Harris, M. Hasan, M. Heffner, E. W. Hoppe, A. House, P. Hufschmidt, M. Hughes, J. Hößl, Y. Ito, A. Iverson, X.S. Jiang, S. Johnston, A. Karelin, L.J. Kaufman, T. Koffas, S. Kravitz, R. Krücken, A. Kuchenkov, K.S. Kumar, Y. Lan, D.S. Leonard, S. Li, Z. Li, C. Licciardi, Y.H. Lin, R. MacLellan, T. Michel, B. Mong, D. Moore, K. Murray, R.J. Newby, Z. Ning, O. Njoya, F. Nolet, K. Odgers, M. Oriunno, J.L. Orrell, I. Ostrovskiy, C.T. Overman, G. S. Ortega, S. Parent, A. Piepke, J.-F. Pratte, V. Radeka, E. Raguzin, T. Rao, S. Rescia, F. Retiere, A. Robinson, T. Rossignol, P.C. Rowson, N. Roy, R. Saldanha, S. Sangiorgio, S. Schmidt, J. Schneider, D. Sinclair, K. Skarpaas, A.K. Soma, G. St-Hilaire, V. Stekhanov, T. Stiegler, X.L. Sun, M. Tarka, J. Todd, T. Tolba, R. Tsang, T. Tsang, F. Vachon, V. Veeraraghavan, G. Visser, J.-L. Vuilleumier, M. Wagenpfeil, M. Weber, W. Wei, U. Wichoski, G. Wrede, S.X. Wu, W.H. Wu, Z. Xuan, L. Yang, D. Yayun, Y.-R. Yen, O. Zeldovich, X. Zhang, J. Zhao, N. Zhe, Y. Zhou, T. Ziegler
Jan. 19, 2018 physics.ins-det
A new design for the anode of a time projection chamber, consisting of a charge-detecting "tile", is investigated for use in large scale liquid xenon detectors. The tile is produced by depositing 60 orthogonal metal charge-collecting strips, 3~mm wide, on a 10~\si{\cm} $\times$ 10~\si{\cm} fused-silica wafer. These charge tiles may be employed by large detectors, such as the proposed tonne-scale nEXO experiment to search for neutrinoless double-beta decay. Modular by design, an array of tiles can cover a sizable area. The width of each strip is small compared to the size of the tile, so a Frisch grid is not required. A grid-less, tiled anode design is beneficial for an experiment such as nEXO, where a wire tensioning support structure and Frisch grid might contribute radioactive backgrounds and would have to be designed to accommodate cycling to cryogenic temperatures. The segmented anode also reduces some degeneracies in signal reconstruction that arise in large-area crossed-wire time projection chambers. A prototype tile was tested in a cell containing liquid xenon. Very good agreement is achieved between the measured ionization spectrum of a $^{207}$Bi source and simulations that include the microphysics of recombination in xenon and a detailed modeling of the electrostatic field of the detector. An energy resolution $\sigma/E$=5.5\% is observed at 570~\si{keV}, comparable to the best intrinsic ionization-only resolution reported in literature for liquid xenon at 936~V/\si{cm}.
Bulk and Surface Event Identification in p-type Germanium Detectors (1611.03357)
L. T. Yang, H. B. Li, H. T. Wong, M. Agartioglu, J. H. Chen, L. P. Jia, H. Jiang, J. Li, F. K. Lin, S. T. Lin, S. K. Liu, J. L. Ma, B. Sevda, V. Sharma, L. Singh, M. K. Singh, M. K. Singh, A. K. Soma, A. Sonay, S. W. Yang, L. Wang, Q. Wang, Q. Yue, W. Zhao
Jan. 8, 2018 hep-ex, physics.ins-det
The p-type point-contact germanium detectors have been adopted for light dark matter WIMP searches and the studies of low energy neutrino physics. These detectors exhibit anomalous behavior to events located at the surface layer. The previous spectral shape method to identify these surface events from the bulk signals relies on spectral shape assumptions and the use of external calibration sources. We report an improved method in separating them by taking the ratios among different categories of in situ event samples as calibration sources. Data from CDEX-1 and TEXONO experiments are re-examined using the ratio method. Results are shown to be consistent with the spectral shape method.
Observation of $^{6}$He+$t$ cluster states in $^{9}$Li (1709.02515)
W. H. Ma, J. S. Wang, D. Patel, Y. Y. Yang, J. B. Ma, S. L. Jin, P. Ma, Q. Hu, Z. Bai, M. R. Huang, X. Q. Liu, Y. J. Zhou, J. Chen, Z. H. Gao, Q. Wang, J. Lubian, J. X. Li, T. F. Wang, S. Mukherjee, X. Y. Ju, Y. S. Yu, T. W. Wu, C. Ni, X. D. Jia, Q. B. Liu, Y. H. Zhang, H. S. Xu, G. Q. Xiao
Jan. 6, 2018 nucl-ex, nucl-th
$^{6}$He+$t$ cluster states of exited $^{9}$Li have been measured by 32.7 MeV/nucleon $^{9}$Li beams bombarding on $^{208}$Pb target. Two resonant states are clearly observed with the excitation energies at 9.8 MeV and 12.6 MeV and spin-parity of 3/2$^{-}$ and 7/2$^{-}$ respectively. These two states are considered to be members of K$^{\pi}$=1/2$^{-}$ band. The spin-parity of them are identified by the method of angular correlation analysis and verified by the continuum discretized coupled channels (CDCC) calculation, which agrees with the prediction of the generator coordinate method (GCM). A monopole matrix element about 4 fm$^{2}$ for the 3/2$^{-}$ state is extracted from the distorted wave Born approximation (DWBA) calculation. These results strongly support the feature of clustering structure of two neutron-rich clusters in the neutron-rich nucleus $^{9}$Li for the first time.
The DArk Matter Particle Explorer mission (1706.08453)
J. Chang, G. Ambrosi, Q. An, R. Asfandiyarov, P. Azzarello, P. Bernardini, B. Bertucci, M. S. Cai, M. Caragiulo, D. Y. Chen, H. F. Chen, J. L. Chen, W. Chen, M. Y. Cui, T. S. Cui, A. D'Amone, A. De Benedittis, I. De Mitri, M. Di Santo, J. N. Dong, T. K. Dong, Y. F. Dong, Z. X. Dong, G. Donvito, D. Droz, K. K. Duan, J. L. Duan, M. Duranti, D. D'Urso, R. R. Fan, Y. Z. Fan, F. Fang, C. Q. Feng, L. Feng, P. Fusco, V. Gallo, F. J. Gan, W. Q. Gan, M. Gao, S. S. Gao, F. Gargano, K. Gong, Y. Z. Gong, J. H. Guo, Y. M. Hu, G. S. Huang, Y. Y. Huang, M. Ionica, D. Jiang, W. Jiang, X. Jin, J. Kong, S. J. Lei, S. Li, X. Li, W. L. Li, Y. Li, Y. F. Liang, Y. M. Liang, N. H. Liao, Q. Z. Liu, H. Liu, J. Liu, S. B. Liu, Q. Z. Liu, W. Q. Liu, Y. Liu, F. Loparco, J. Lü, M. Ma, P. X. Ma, S. Y. Ma, T. Ma, X. Q. Ma, X. Y. Ma, G. Marsella, M.N. Mazziotta, D. Mo, T. T. Miao, X. Y. Niu, M. Pohl, X. Y. Peng, W. X. Peng, R. Qiao, J. N. Rao, M. M. Salinas, G. Z. Shang, W. H. Shen, Z. Q. Shen, Z. T. Shen, J. X. Song, H. Su, M. Su, Z. Y. Sun, A. Surdo, X. J. Teng, X. B. Tian, A. Tykhonov, V. Vagelli, S. Vitillo, C. Wang, Chi Wang, H. Wang, H. Y. Wang, J. Z. Wang, L. G. Wang, Q. Wang, S. Wang, X. H. Wang, X. L. Wang, Y. F. Wang, Y. P. Wang, Y. Z. Wang, S. C. Wen, Z. M. Wang, D. M. Wei, J. J. Wei, Y. F. Wei, D. Wu, J. Wu, S. S. Wu, X. Wu, K. Xi, Z. Q. Xia, Y. L. Xin, H. T. Xu, Z. L. Xu, Z. Z. Xu, G. F. Xue, H. B. Yang, J. Yang, P. Yang, Y. Q. Yang, Z. L. Yang, H. J. Yao, Y. H. Yu, Q. Yuan, C. Yue, J. J. Zang, C. Zhang, D. L. Zhang, F. Zhang, J. B. Zhang, J. Y. Zhang, J. Z. Zhang, L. Zhang, P. F. Zhang, S. X. Zhang, W. Z. Zhang, Y. Zhang, Y. J. Zhang, Y. Q. Zhang, Y. L. Zhang, Y. P. Zhang, Z. Zhang, Z. Y. Zhang, H. Zhao, H. Y. Zhao, X. F. Zhao, C. Y. Zhou, Y. Zhou, X. Zhu, Y. Zhu, S. Zimmer
Sept. 14, 2017 hep-ex, physics.ins-det, astro-ph.IM, astro-ph.HE
The DArk Matter Particle Explorer (DAMPE), one of the four scientific space science missions within the framework of the Strategic Pioneer Program on Space Science of the Chinese Academy of Sciences, is a general purpose high energy cosmic-ray and gamma-ray observatory, which was successfully launched on December 17th, 2015 from the Jiuquan Satellite Launch Center. The DAMPE scientific objectives include the study of galactic cosmic rays up to $\sim 10$ TeV and hundreds of TeV for electrons/gammas and nuclei respectively, and the search for dark matter signatures in their spectra. In this paper we illustrate the layout of the DAMPE instrument, and discuss the results of beam tests and calibrations performed on ground. Finally we present the expected performance in space and give an overview of the mission key scientific goals.
Quantum speed limit for relativistic spin-0 and spin-1 bosons on commutative and noncommutative planes (1703.01063)
K. Wang, Y.F. Zhang, Q. Wang, Z.W. Long, J. Jing
May 15, 2017 hep-th
Quantum speed limits of relativistic charged spin-0 and spin-1 bosons in the background of a homogeneous magnetic field are studied on both commutative and oncommutative planes. We show that, on the commutative plane, the average speeds of wave packets along the radial direction during the interval in which a quantum state evolving from an initial state to the orthogonal final one can not exceed the speed of light, regardless of the intensities of the magnetic field. However, due to the noncommutativity, the average speeds of the wave packets on noncommutative plane will exceed the speed of light in vacuum provided the intensity of the magnetic field is strong enough. It is a clear signature of violating Lorentz invariance in quantum mechanics region.
Stimulated Brillouin scattering behaviors in different species ignition hohlraum plasmas in high-temperature and high-density region (1704.02317)
Q. S. Feng, C. Y. Zheng, Z. J. Liu, Q. Wang, C. Z. Xiao, L. H. Cao, X. T. He
April 5, 2017 physics.plasm-ph
The presence of multiple ion species can add additional branches to the IAW dispersion relation and change the Landau damping significantly. Different IAW modes excited by stimulated Brillouin scattering (SBS) and different SBS behaviors in several typical ignition hohlraum plasmas in the high-temperature and high-density region have been researched by Vlasov-Maxwell simulation. The slow mode in HeH or CH plasmas is the least damped mode and will be excited in SBS, while the fast mode in AuB plasmas is the least damped mode and will be excited in SBS. Due to strong Landau damping, the SBS in H or HeH plasmas is strong convective instability, while the SBS in AuB plasmas is absolute instability due to the weak Landau damping. However, although the SBS in CH plasmas is weak convective instability in the linear theory, the SBS will transform into absolute instability due to decreasing linear Landau damping by particles trapping. These results give a detail research of the IAW modes excitation and the properties of SBS in different species plasmas, thus providing the possibility of controlling SBS by increasing the linear Landau damping of the IAW by changing ion species.
Evidence of topological insulator state in the semimetal LaBi (1612.03589)
R. Lou, B.-B. Fu, Q. N. Xu, P.-J. Guo, L.-Y. Kong, L.-K. Zeng, J.-Z. Ma, P. Richard, C. Fang, Y.-B. Huang, S.-S. Sun, Q. Wang, L. Wang, Y.-G. Shi, H. C. Lei, K. Liu, H. M. Weng, T. Qian, H. Ding, S.-C. Wang
March 23, 2017 cond-mat.mtrl-sci, cond-mat.mes-hall
By employing angle-resolved photoemission spectroscopy combined with first-principles calculations, we performed a systematic investigation on the electronic structure of LaBi, which exhibits extremely large magnetoresistance (XMR), and is theoretically predicted to possess band anticrossing with nontrivial topological properties. Here, the observations of the Fermi-surface topology and band dispersions are similar to previous studies on LaSb [Phys. Rev. Lett. 117, 127204 (2016)], a topologically trivial XMR semimetal, except the existence of a band inversion along the $\Gamma$-$X$ direction, with one massless and one gapped Dirac-like surface state at the $X$ and $\Gamma$ points, respectively. The odd number of massless Dirac cones suggests that LaBi is analogous to the time-reversal $Z_2$ nontrivial topological insulator. These findings open up a new series for exploring novel topological states and investigating their evolution from the perspective of topological phase transition within the family of rare-earth monopnictides.
Controlling thermal emission of phonon by magnetic metasurfaces (1702.04301)
X. Zhang, H. Liu, Z. G. Zhang, Q. Wang, S. N. Zhu
Feb. 11, 2017 physics.class-ph, cond-mat.mtrl-sci, physics.optics
Our experiment shows that the thermal emission of phonon can be controlled by magnetic resonance (MR) mode in a metasurface (MTS). Through changing the structural parameter of metasurface, the MR wavelength can be tuned to the phonon resonance wavelength. This introduces a strong coupling between phonon and MR, which results in an anticrossing phonon-plasmons mode. In the process, we can manipulate the polarization and angular radiation of thermal emission of phonon. Such metasurface provides a new kind of thermal emission structures for various thermal management applications.
Anti-Stokes scattering and Stokes scattering of stimulated Brillouin scattering cascade in high-intensity laser-plasmas interaction (1701.04799)
Q. S. Feng, Z. J. Liu, C. Y. Zheng, C. Z. Xiao, Q. Wang, L. H. Cao, X. T. He
Jan. 17, 2017 physics.plasm-ph
The anti-Stokes scattering and Stokes scattering in stimulated Brillouin scattering (SBS) cascade have been researched by the Vlasov-Maxwell simulation. In the high-intensity laser-plasmas interaction, the stimulated anti-Stokes Brillouin scattering (SABS) will occur after the second stage SBS rescattering. The mechanism of SABS has been put forward to explain this phenomenon. And the SABS will compete with the SBS rescattering to determine the total SBS reflectivity. Thus, the SBS rescattering including the SABS is an important saturation mechanism of SBS, and should be taken into account in the high-intensity laser-plasmas interaction.
Suppression of Stimulated Raman Scattering and Hot Electrons Generation due to Langmuir Decay Instability Cascade and Langmuir Collapse (1612.01252)
Q. S. Feng, C. Y. Zheng, Z. J. Liu, L. H. Cao, Q. Wang, C. Z. Xiao, X. T. He
Dec. 5, 2016 physics.plasm-ph
Backward stimulated Raman scattering (BSRS) with Langmuir decay instability (LDI) and Langmuir collapse has been researched by Vlasov simulation for the first time. The decay productions of LDI cascade and their evolution with time is clearly demonstrated, which occurs simultaneously with Langmuir collapse. The BSRS reflectivity will be decreased largely through LDI cascade and Langmuir collapse. In CH plasmas, when $T_i/T_e=1/3$, the Landau damping of the slow ion-acoustic wave (IAW) is lower than that in H plasmas. Therefore, the BSRS can be further suppressed through LDI cascade by the way of controlling the species of plasmas and ions ratio. These results give an effective mechanism to suppress the BSRS and hot electrons generation.
Characteristics of superconducting tungsten silicide WxSi1-x for single photon detection (1607.07854)
X. Zhang, A. Engel, Q. Wang, A. Schilling, A. Semenov, M. Sidorova, H.-W. Hübers, I. Charaev, K. Ilin, M. Siegel
Nov. 14, 2016 cond-mat.supr-con
Superconducting properties of three series of amorphous WxSi1-x films with different thickness and stoichiometry were investigated by dc transport measurements in a magnetic field up to 9 T. These amorphous WxSi1-x films were deposited by magnetron co-sputtering of the elemental source targets onto silicon substrates at room temperature and patterned in form of bridges by optical lithography and reactive ion etching. Analysis of the data on magnetoconductivity allowed us to extract the critical temperature, superconducting coherence length, magnetic penetration depth, and diffusion coefficient of electrons in the normal state as a function of film thickness for each stoichiometry. Two basic time constants were derived from transport and time-resolving measurements. A dynamic process of the formation of a hot-spot was analyzed in the framework of a diffusion-based vortex-entry model. We used the two stage diffusion approach and defined a hotspot size by assuming that the quasi-particles and normal-state electrons have the equal diffusion constant. Our findings are consistent with the most recent results on a hot-spot relaxation time in the WxSi1-x superconducting nanowire single-photon detector. In the 5 nm thick W0.85Si0.15 film the hot-spot has a diameter of 105 nm at the peak of the number of non-equilibrium quasi-particles.
Superconducting single X-ray photon detector based on W0.8Si0.2 (1608.02347)
X. Zhang, Q. Wang, A. Schilling
Oct. 28, 2016 cond-mat.supr-con, physics.ins-det
We fabricated a superconducting single X-ray photon detector based on W0.8Si0.2, and we characterized its basic detection performance for keV-photons at different temperatures. The detector has a critical temperature of 4.97 K, and it is able to be operated up to 4.8 K, just below the critical temperature. The detector starts to react to X-ray photons at relatively low bias currents, less than 1% of Ic at T = 1.8 K, and it shows a saturated count rate dependence on bias current at all temperatures, indicating that the optimum internal quantum efficiency can always be reached. Dark counts are negligible up to the highest investigated bias currents (99% of Ic) and operating temperature (4.8 K). The latching effect affects the detector performance at all temperatures due to the fast recovery of the bias current; however, further modifications of the device geometry are expected to reduce the tendency for latching.
Constraints on Axion couplings from the CDEX-1 experiment at the China Jinping Underground Laboratory (1610.07521)
S.K. Liu, Q. Yue, K.J. Kang, J.P. Cheng, H.T. Wong, Y.J. Li, H.B. Li, S.T. Lin, J.P. Chang, J.H. Chen, N. Chen, Q.H. Chen, Y.H. Chen, Z. Deng, Q. Du, H. Gong, H.J. He, Q.J. He, H.X. Huang, H. Jiang, J.M. Li, J. Li, J. Li, X. Li, X.Q. Li, X.Y. Li, Y.L. Li, F.K. Lin, L.C. Lü, H. Ma, J.L. Ma, S.J. Mao, J.Q. Qin, J. Ren, J. Ren, X.C. Ruan, V. Sharma, M.B. Shen, L. Singh, M.K. Singh, A.K. Soma, J. Su, C.J. Tang, J.M. Wang, L. Wang, Q. Wang, S.Y. Wu, Y.C. Wu, Y.C. Wu, Z.Z. Xianyu, R.Q. Xiao, H.Y. Xing, F.Z. Xu, Y. Xu, X.J. Xu, T. Xue, C.W. Yang, L.T. Yang, S.W. Yang, N. Yi, C.X. Yu, H. Yu, X.Z. Yu, X.H. Zeng, Z. Zeng, L. Zhang, Y.H. Zhang, M.G. Zhao, W. Zhao, Z.Y. Zhou, J.J. Zhu, W.B. Zhu, X.Z. Zhu, Z.H. Zhu
Oct. 24, 2016 hep-ph, hep-ex, physics.ins-det
We report the results of searches for solar axions and galactic dark matter axions or axion-like particles with CDEX-1 experiment at the China Jinping Underground Laboratory, using 335.6 kg-days of data from a p-type point-contact germanium detector. The data are compatible with the background model and no excess signals are observed. Limits of solar axions on the model independent coupling $g_{Ae}<2.5\times10^{-11}$ from Compton, bremsstrahlung, atomic-recombination and deexcitation channel and $g^{\text{eff}}_{AN}\times g_{Ae}<6.1\times10^{-17}$ from $^{57}$Fe M1 transition at 90 % confidence level are derived. Within the framework of the DFSZ and KSVZ models, our results exclude the axion mass heavier than 0.9 eV/c$^{2}$ and 173 eV/c$^{2}$, respectively. The derived constraints for dark matter axions below 1 keV improves over the previous results.
Compensated semimetal LaSb with unsaturated magnetoresistance (1604.08142)
L.-K. Zeng, R. Lou, D.-S. Wu, Q. N. Xu, P.-J. Guo, L.-Y. Kong, Y.-G. Zhong, J.-Z. Ma, B.-B. Fu, P. Richard, P. Wang, G. T. Liu, L. Lu, Y.-B. Huang, C. Fang, S.-S. Sun, Q. Wang, L. Wang, Y.-G. Shi, H. M. Weng, H.-C. Lei, K. Liu, S.-C. Wang, T. Qian, J.-L. Luo, H. Ding
Sept. 19, 2016 cond-mat.mtrl-sci, cond-mat.mes-hall
By combining angle-resolved photoemission spectroscopy and quantum oscillation measurements, we performed a comprehensive investigation on the electronic structure of LaSb, which exhibits near-quadratic extremely large magnetoresistance (XMR) without any sign of saturation at magnetic fields as high as 40 T. We clearly resolve one spherical and one intersecting-ellipsoidal hole Fermi surfaces (FSs) at the Brillouin zone (BZ) center $\Gamma$ and one ellipsoidal electron FS at the BZ boundary $X$. The hole and electron carriers calculated from the enclosed FS volumes are perfectly compensated, and the carrier compensation is unaffected by temperature. We further reveal that LaSb is topologically trivial but share many similarities with the Weyl semimetal TaAs family in the bulk electronic structure. Based on these results, we have examined the mechanisms that have been proposed so far to explain the near-quadratic XMR in semimetals.
Emergence of topological bands on the surface of ZrSnTe crystal (1601.07294)
R. Lou, J.-Z. Ma, Q.-N. Xu, B.-B. Fu, L.-Y. Kong, Y.-G. Shi, P. Richard, H.-M. Weng, Z. Fang, S.-S. Sun, Q. Wang, H.-C. Lei, T. Qian, H. Ding, S.-C. Wang
By using angle-resolved photoemission spectroscopy combined with first-principles calculations, we reveal that the topmost unit cell of ZrSnTe crystal hosts two-dimensional (2D) electronic bands of topological insulator (TI) state, though such a TI state is defined with a curved Fermi level instead of a global band gap. Furthermore, we find that by modifying the dangling bonds on the surface through hydrogenation, this 2D band structure can be manipulated so that the expected global energy gap is most likely to be realized. This facilitates the practical applications of 2D TI in heterostructural devices and those with surface decoration and coverage. Since ZrSnTe belongs to a large family of compounds having the similar crystal and band structures, our findings shed light on identifying more 2D TI candidates and superconductor-TI heterojunctions supporting topological superconductors.
Harmonics Effect on Ion-Bulk Waves in CH Plasmas (1609.02280)
Q. S. Feng, C. Y. Zheng, Z. J. Liu, L. H. Cao, C. Z. Xiao, Q. Wang, , X. T. He
Sept. 8, 2016 physics.plasm-ph
The harmonics effect on ion-bulk (IBk) waves has been researched by Vlasov simulation. The condition of excitation of a large-amplitude IBk waves is given to explain the phenomenon of strong short-wavelength electrostatic activity in solar wind. When $k$ is much lower than $k_{lor}/2$ ($k_{lor}$ is the wave number at loss-of-resonance point), the IBk waves will not be excited to a large amplitude, because a large part of energy will be spread to harmonics. The nature of nonlinear IBk waves in the condition of $k<k_{lor}/2$ is undamped Bernstein-Greene-Kruskal-like waves with harmonics superposition. Only when the wave number $k$ of IBk waves satisfies $k_{lor}/2\lesssim k\leq k_{lor}$, can a large-amplitude and mono-frequency IBk wave be excited. These results give a guidance for a novel scattering mechanism related to IBk waves in the field of laser plasma interaction.
The correlation between quarter point angle and nuclear radius (1601.04401)
W. H. Ma, J. S. Wang, S. Mukherjee, Q. Wang, D. Patel, Y. Y. Yang, J. B. Ma, P. Ma, S. L. Jin, Z. Bai, X. Q. Liu
Aug. 15, 2016 nucl-th
The main objective of the present work is to correlate quarter-point angle and nuclear radius or nuclear matter distribution. Various phenomenological formulae with parameters for strong absorption radius Rs are obtained and compared by fitting the experimental data of quarter point angle extracted from nuclear elastic scattering reaction systems. The parameterized formula of Rs related to the isospin and binding energy is recommended, that gives a good reproduction of nuclear matter radii of halo nuclei.
Fluid nonlinear frequency shift of nonlinear ion acoustic waves in multi-ion species plasmas in small wave number region (1608.03923)
Q. S. Feng, C. Z. Xiao, Q. Wang, C. Y. Zheng, Z. J. Liu, L. H. Cao, , X. T. He
Aug. 12, 2016 physics.plasm-ph
The properties of the nonlinear frequency shift (NFS) especially the fluid NFS from the harmonic generation of the ion-acoustic wave (IAW) in multi-ion species plasmas have been researched by Vlasov simulation. The pictures of the nonlinear frequency shift from harmonic generation and particles trapping are shown to explain the mechanism of NFS qualitatively. The theoretical model of the fluid NFS from harmonic generation in multi-ion species plasmas is given and the results of Vlasov simulation are consistent to the theoretical result of multi-ion species plasmas. When the wave number $k\lambda_{De}$ is small, such as $k\lambda_{De}=0.1$, the fluid NFS dominates in the total NFS and will reach as large as nearly $15\%$ when the wave amplitude $|e\phi/T_e|\sim0.1$, which indicates that in the condition of small $k\lambda_{De}$, the fluid NFS dominates in the saturation of stimulated Brillouin scattering especially when the nonlinear IAW amplitude is large.
Excitation of nonlinear ion acoustic waves in CH plasmas (1607.06598)
Q. S. Feng, C. Y. Zheng, Z. J. Liu, C. Z. Xiao, Q. Wang, X. T. He
July 22, 2016 physics.plasm-ph
Excitation of nonlinear ion acoustic wave (IAW) by an external electric field is demonstrated by Vlasov simulation. The frequency calculated by the dispersion relation with no damping is verified much closer to the resonance frequency of the small-amplitude nonlinear IAW than that calculated by the linear dispersion relation. When the wave number $ k\lambda_{De} $ increases, the linear Landau damping of the fast mode (its phase velocity is greater than any ion's thermal velocity) increases obviously in the region of $ T_i/T_e < 0.2 $ in which the fast mode is weakly damped mode. As a result, the deviation between the frequency calculated by the linear dispersion relation and that by the dispersion relation with no damping becomes larger with $k\lambda_{De}$ increasing. When $k\lambda_{De}$ is not large, such as $k\lambda_{De}=0.1, 0.3, 0.5$, the nonlinear IAW can be excited by the driver with the linear frequency of the modes. However, when $k\lambda_{De}$ is large, such as $k\lambda_{De}=0.7$, the linear frequency can not be applied to exciting the nonlinear IAW, while the frequency calculated by the dispersion relation with no damping can be applied to exciting the nonlinear IAW.