Faculty Publications: June, 2017

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Title:
The Titan Haze Simulation Experiment: Latest Laboratory Results and Dedicated Plasma Chemistry Model
Authors:
Sciamma-O'Brien, Ella; Raymond, Alexander; Mazur, Eric; Salama, Farid
Publication:
American Astronomical Society, AAS Meeting #230, id.#302.02
Publication Date:
06/2017
Origin:
AAS
Abstract Copyright:
(c) 2017: American Astronomical Society
Bibliographic Code:
2017AAS...23030202S

Abstract

In Titan’s atmosphere, a complex organic chemistry occurs between its main constituents, N2 and CH4, and leads to the production of larger molecules and solid aerosols.Here, we present the latest results on the gas and solid phase analyses in the Titan Haze Simulation (THS) experiment, developed on the NASA Ames COSmIC simulation chamber. The THS is a unique experimental platform that allows us to simulate Titan’s atmospheric chemistry at Titan-like temperature (200K) by cooling down N2-CH4-based mixtures in a supersonic expansion before inducing the chemistry by plasma. Because of the accelerated gas flow in the expansion, the residence time of the gas in the active plasma region is less than 3 µs. This results in a truncated chemistry that enables us to monitor the first and intermediate steps of the chemistry as well as specific chemical pathways when adding, in the initial gas mixture, heavier molecules that have been detected as trace elements on Titan[1].We discuss the results of recent Mid-infrared (MIR) spectroscopy[2] and X-ray Absorption Near Edge Structure spectroscopy studies of THS Titan tholins produced in different gas mixtures (with and without acetylene and benzene). Both studies have shown the presence of nitrogen chemistry, and differences in the level and nature of the nitrogen incorporation depending on the initial gas mixture. A comparison of THS MIR spectra to VIMS data has shown that the THS aerosols produced in simpler mixtures, i.e., that contain more nitrogen and where the N-incorporation is in isocyanide-type molecules instead of nitriles, are more representative of Titan’s aerosols.In addition, a new model has been developed to simulate the plasma chemistry in the THS. Electron impact and chemical kinetics equations for more than 120 species are followed. The calculated mass spectra are in good agreement with the experimental THS mass spectra[1], confirming that the short residence time in the plasma cavity limits the growth of larger species and results in a truncated chemistry, a main feature of the THS.References:[1] Sciamma-O'Brien E. et al., Icarus, 243, 325 (2014)[2] Sciamma-O'Brien E. et al., Icarus, in press (2017) .

 

Title:
Tough self-healing elastomers by molecular enforced integration of covalent and reversible networks
Authors:
Wu, Jinrong; Cai, Li-Heng; Weitz, David A.
Publication:
eprint arXiv:1706.00501
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
Condensed Matter - Materials Science, Condensed Matter - Soft Condensed Matter
Bibliographic Code:
2017arXiv170600501W

Abstract

Self-healing polymers crosslinked by solely reversible bonds are intrinsically weaker than common covalently crosslinked networks. Introducing covalent crosslinks into a reversible network would improve mechanical strength. It is challenging, however, to apply this design concept to dry elastomers, largely because reversible crosslinks such as hydrogen bonds are often polar motifs, whereas covalent crosslinks are non-polar motifs, and these two types of bonds are intrinsically immiscible without co-solvents. Here we design and fabricate a hybrid polymer network by crosslinking randomly branched polymers carrying motifs that can form both reversible hydrogen bonds and permanent covalent crosslinks. The randomly branched polymer links such two types of bonds and forces them to mix on the molecular level without co-solvents. This allows us to create a hybrid dry elastomer that is very tough with a fracture energy $13,500J/m^2$ comparable to that of natural rubber; moreover, the elastomer can self-heal at room temperature with a recovered tensile strength 4 MPa similar to that of existing self-healing elastomers. The concept of forcing covalent and reversible bonds to mix at molecular scale to create a homogenous network is quite general and should enable development of tough, self-healing polymers of practical usage.

 

Title:
Guided Modes of Anisotropic van der Waals Materials Investigated by Near-Field Scanning Optical Microscopy
Authors:
Wintz, Daniel; Chaudhary, Kundan; Wang, Ke; Jauregui, Luis A.; Ambrosio, Antonio; Tamagnone, Michele; Zhu, Alexander Y.; Devlin, Robert C.; Crossno, Jesse D.; Pistunova, Kateryna; Watanabe, Kenji; Taniguchi, Takashi; Kim, Philip; Capasso, Federico
Publication:
eprint arXiv:1706.00708
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
Physics - Optics, Condensed Matter - Mesoscale and Nanoscale Physics
Bibliographic Code:
2017arXiv170600708W

Abstract

Guided modes in anisotropic two-dimensional van der Waals materials are experimentally investigated and their refractive indices in visible wavelengths are extracted. Our method involves near-field scanning optical microscopy of waveguide (transverse electric) and surface plasmon polariton (transverse magnetic) modes in h-BN/SiO2/Si and Ag/h-BN stacks, respectively. We determine the dispersion of these modes and use this relationship to extract anisotropic refractive indices of h-BN flakes. In the wavelength interval 550-700 nm, the in-plane and out-of-plane refractive indices are in the range 1.98-2.12 and 1.45-2.12, respectively. Our approach of using near-field scanning optical microscopy allows for direct study of interaction between light and two-dimensional van der Waals materials and heterostructures.

 

Title:
An infinite family of 3d Floquet topological paramagnets
Authors:
Potter, Andrew C.; Vishwanath, Ashvin; Fidkowski, Lukasz
Publication:
eprint arXiv:1706.01888
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Disordered Systems and Neural Networks
Comment:
4+9 pages, 8 figures
Bibliographic Code:
2017arXiv170601888P

Abstract

We uncover an infinite family of time-reversal symmetric 3d interacting topological insulators of bosons or spins, in time-periodically driven systems, which we term Floquet topological paramagnets (FTPMs). These FTPM phases exhibit intrinsically dynamical properties that could not occur in thermal equilibrium, and are governed by an infinite set of $Z_2$-valued topological invariants, one for each prime number. The topological invariants are physically characterized by surface magnetic domain walls that act as unidirectional quantum channels, transferring quantized packets of information during each driving period. We construct exactly solvable models realizing each of these phases, and discuss the anomalous dynamics of their topologically protected surface states. Unlike previous encountered examples of Floquet SPT phases, these 3d FTPMs are not captured by group cohomology methods, and cannot be obtained from equilibrium classifications simply by treating the discrete time-translation as an ordinary symmetry. The simplest such FTPM phase can feature anomalous $Z_2$ (toric code) surface topological order, in which the gauge electric and magnetic excitations are exchanged in each Floquet period, which cannot occur in a pure 2d system without breaking time reversal symmetry.

 

Title:
Symmetry-protected dissipative preparation of matrix product states
Authors:
Zhou, Leo; Choi, Soonwon; Lukin, Mikhail D.
Publication:
eprint arXiv:1706.01995
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
Quantum Physics
Bibliographic Code:
2017arXiv170601995Z

Abstract

We propose and analyze a method for efficient dissipative preparation of matrix product states that exploits their symmetry properties. Specifically, we construct an explicit protocol that makes use of driven-dissipative dynamics to prepare the Affleck-Kennedy-Lieb-Tasaki (AKLT) states, which features symmetry-protected topological order and non-trivial edge excitations. We show that the use of symmetry allows for robust experimental implementation without fine-tuned control parameters. Numerical simulations show that the preparation time scales polynomially in system size $n$. Furthermore, we demonstrate that this scaling can be improved to $\mathcal{O}(\log^2n)$ by using parallel preparation of AKLT segments and fusing them via quantum feedback. A concrete scheme using excitation of trapped neutral atoms into Rydberg state via Electromagnetically Induced Transparency is proposed, and generalizations to a broader class of matrix product states are discussed.

 

Title:
CMB-S4 Technology Book, First Edition
Authors:
Abitbol, Maximilian H.; Ahmed, Zeeshan; Barron, Darcy; Basu Thakur, Ritoban; Bender, Amy N.; Benson, Bradford A.; Bischoff, Colin A.; Bryan, Sean A.; Carlstrom, John E.; Chang, Clarence L.; Chuss, David T.; Cukierman, Ari; de Haan, Tijmen; Dobbs, Matt; Essinger-Hileman, Tom; Filippini, Jeffrey P.; Ganga, Ken; Gudmundsson, Jon E.; Halverson, Nils W.; Hanany, Shaul; Henderson, Shawn W.; Hill, Charles A.; Ho, Shuay-Pwu P.; Hubmayr, Johannes; Irwin, Kent; Jeong, Oliver; Johnson, Bradley R.; Kernasovskiy, Sarah A.; Kovac, John M.; Kusaka, Akito; Lee, Adrian T.; Maria, Salatino; Mauskopf, Philip; McMahon, Jeff J.; Moncelsi, Lorenzo; Nadolski, Andrew W.; Nagy, Johanna M.; Niemack, Michael D.; O'Brient, Roger C.; Padin, Stephen; Parshley, Stephen C.; Pryke, Clement; Roe, Natalie A.; Rostem, Karwan; Ruhl, John; Simon, Sara M.; Staggs, Suzanne T.; Suzuki, Aritoki; Switzer, Eric R.; Thompson, Keith L.; Timbie, Peter; Tucker, Gregory S.; Vieira, Joaquin D.; Vieregg, Abigail G.; Westbrook, Benjamin; Wollack, Edward J.; Yoon, Ki Won; Young, Karl S.; Young, Edward Y.
Publication:
eprint arXiv:1706.02464
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
Astrophysics - Instrumentation and Methods for Astrophysics
Comment:
191 pages
Bibliographic Code:
2017arXiv170602464A

Abstract

CMB-S4 is a proposed experiment to map the polarization of the Cosmic Microwave Background (CMB) to nearly the cosmic variance limit for the angular scales that are accessible from the ground. The science goals and capabilities of CMB-S4 in illuminating cosmic inflation, measuring the sum of neutrino masses, searching for relativistic relics in the early universe, characterizing dark energy and dark matter, and mapping the matter distribution in the universe have been described in the CMB-S4 Science Book. This Technology Book is a companion volume to the Science Book. The ambitious science goals of the proposed "Stage-IV" CMB-S4 will require a step forward in experimental capability from the current Stage-III experiments. To guide this process, the community summarized the current state of the technology and identify R&D efforts necessary to advance it for possible use in CMB-S4. The book focused on the technical challenges in four broad areas: Telescope Design; Receiver Optics; Focal-Plane Optical Coupling; and Focal-Plane Sensor and Readout.

 

Title:
Mirror of Atiyah flop in symplectic geometry and stability conditions
Authors:
Fan, Yu-Wei; Hong, Hansol; Lau, Siu-Cheong; Yau, Shing-Tung
Publication:
eprint arXiv:1706.02942
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
Mathematics - Symplectic Geometry, Mathematics - Algebraic Geometry, 53D37, 14J33
Comment:
v2: 45 pages, 18 figures; revised exposition
Bibliographic Code:
2017arXiv170602942F

Abstract

We study the mirror operation of the Atiyah flop in symplectic geometry. We formulate the operation for a symplectic manifold with a Lagrangian fibration. Furthermore we construct geometric stability conditions on the derived Fukaya category of the deformed conifold and study the action of the mirror Atiyah flop on these stability conditions.

 

Title:
Creation of Rydberg Polarons in a Bose Gas
Authors:
Camargo, F.; Schmidt, R.; Whalen, J. D.; Ding, R.; Woehl, G., Jr.; Yoshida, S.; Burgdorfer, J.; Dunning, F. B.; Sadeghpour, H. R.; Demler, E.; Killian, T. C.
Publication:
eprint arXiv:1706.03717
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
Quantum Physics
Bibliographic Code:
2017arXiv170603717C

Abstract

We report spectroscopic observation of Rydberg polarons in a Bose gas. Polarons are created by excitation of Rydberg atoms in a strontium Bose-Einstein condensate, and they are distinguished by occupation of bound molecular states that arise from scattering between the loosely bound Rydberg electron and ground-state atoms. All spectral features are described with a functional determinant theory that solves an extended Frohlich Hamiltonian for an impurity in a Bose gas. Detailed analysis of the red-detuned tail of the excitation spectrum, which describes the contribution from the region of highest density in the condensate, reveals the intrinsic excitation spectrum of Rydberg polarons.

 

Title:
Engineering a diamond spin-qubit with a nano-electro-mechanical system
Authors:
Sohn, Young-Ik; Meesala, Srujan; Pingault, Benjamin; Atikian, Haig A.; Holzgrafe, Jeffrey; Gundogan, Mustafa; Stavrakas, Camille; Stanley, Megan J.; Sipahigil, Alp; Choi, Joonhee; Zhang, Mian; Pacheco, Jose L.; Abraham, John; Bielejec, Edward; Lukin, Mikhail D.; Atature, Mete; Loncar, Marko
Publication:
eprint arXiv:1706.03881
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
Quantum Physics, Condensed Matter - Mesoscale and Nanoscale Physics
Bibliographic Code:
2017arXiv170603881S

Abstract

The realisation of a distributed quantum network requires long-lived memory qubits such as electron spins efficiently interfaced with indistinguishable optical photons. Due to dynamic fluctuations in the solid-state environment, it remains a challenge to identify a solid-state emitter that simultaneously offers excellent optical properties and long-lived qubit coherence. Specifically, the impact of thermal phonons is irreversible, and fundamentally limits qubit coherence. Here, we employ silicon-vacancy (SiV) colour centres in diamond, known for their excellent optical properties, and demonstrate an approach to improve their phonon-limited spin coherence. Using a diamond nano-electro-mechanical system (NEMS), we control the SiV electronic structure by tuning strain, allowing us to both probe and quench the interaction of the colour centre with phonons. This approach also provides a scalable platform to overcome optical inhomogeneity among emitters. The large wavelength tunability and improved spin coherence that we demonstrate make the SiV an attractive platform for the realisation of a quantum network.

 

Title:
Gluon Amplitudes as 2d Conformal Correlators
Authors:
Pasterski, Sabrina; Shao, Shu-Heng; Strominger, Andrew
Publication:
eprint arXiv:1706.03917
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
High Energy Physics - Theory
Comment:
27 pages
Bibliographic Code:
2017arXiv170603917P

Abstract

Recently, spin-one wavefunctions in four dimensions that are conformal primaries of the Lorentz group SL(2,C) were constructed. We compute low-point, tree-level gluon scattering amplitudes in the space of these conformal primary wavefunctions. The answers have the same conformal covariance as correlators of spin-one primaries in a 2d CFT. The BCFW recursion relation between three- and four-point gluon amplitudes is recast into this conformal basis.

 

Title:
Point Sources from Dissipative Dark Matter
Authors:
Agrawal, Prateek; Randall, Lisa
Publication:
eprint arXiv:1706.04195
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
High Energy Physics - Phenomenology, Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena
Comment:
20 pages, 8 figures, 1 table
Bibliographic Code:
2017arXiv170604195A

Abstract

If a component of dark matter has dissipative interactions, it can cool to form compact astrophysical objects with higher density than that of conventional cold dark matter (sub)haloes. Dark matter annihilations might then appear as point sources, leading to novel morphology for indirect detection. We explore dissipative models where interaction with the Standard Model might provide visible signals, and show how such objects might give rise to the observed excess in gamma rays arising from the galactic center.

 

Title:
Exploring Cosmic Origins with CORE: Survey requirements and mission design
Authors:
Delabrouille, J.; de Bernardis, P.; Bouchet, F. R.; Achúcarro, A.; Ade, P. A. R.; Allison, R.; Arroja, F.; Artal, E.; Ashdown, M.; Baccigalupi, C.; Ballardini, M.; Banday, A. J.; Banerji, R.; Barbosa, D.; Bartlett, J.; Bartolo, N.; Basak, S.; Baselmans, J. J. A.; Basu, K.; Battistelli, E. S.; Battye, R.; Baumann, D.; Benoît, A.; Bersanelli, M.; Bideaud, A.; Biesiada, M.; Bilicki, M.; Bonaldi, A.; Bonato, M.; Borrill, J.; Boulanger, F.; Brinckmann, T.; Brown, M. L.; Bucher, M.; Burigana, C.; Buzzelli, A.; Cabass, G.; Cai, Z.-Y.; Calvo, M.; Caputo, A.; Carvalho, C.-S.; Casas, F. J.; Castellano, G.; Catalano, A.; Challinor, A.; Charles, I.; Chluba, J.; Clements, D. L.; Clesse, S.; Colafrancesco, S.; Colantoni, I.; Contreras, D.; Coppolecchia, A.; Crook, M.; D'Alessandro, G.; D'Amico, G.; da Silva, A.; de Avillez, M.; de Gasperis, G.; De Petris, M.; de Zotti, G.; Danese, L.; Désert, F.-X.; Desjacques, V.; Di Valentino, E.; Dickinson, C.; Diego, J. M.; Doyle, S.; Durrer, R.; Dvorkin, C.; Eriksen, H.-K.; Errard, J.; Feeney, S.; Fernández-Cobos, R.; Finelli, F.; Forastieri, F.; Franceschet, C.; Fuskeland, U.; Galli, S.; Génova-Santos, R. T.; Gerbino, M.; Giusarma, E.; Gomez, A.; González-Nuevo, J.; Grandis, S.; Greenslade, J.; Goupy, J.; Hagstotz, S.; Hanany, S.; Handley, W.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Hervias-Caimapo, C.; Hills, M.; Hindmarsh, M.; Hivon, E.; Hoang, D. T.; Hooper, D. C.; Hu, B.; Keihänen, E.; Keskitalo, R.; Kiiveri, K.; Kisner, T.; Kitching, T.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamagna, L.; Lapi, A.; Lasenby, A.; Lattanzi, M.; Le Brun, A. M. C.; Lesgourgues, J.; Liguori, M.; Lindholm, V.; Lizarraga, J.; Luzzi, G.; Macìas-Pérez, J. F.; Maffei, B.; Mandolesi, N.; Martin, S.; Martinez-Gonzalez, E.; Martins, C. J. A. P.; Masi, S.; Massardi, M.; Matarrese, S.; Mazzotta, P.; McCarthy, D.; Melchiorri, A.; Melin, J.-B.; Mennella, A.; Mohr, J.; Molinari, D.; Monfardini, A.; Montier, L.; Natoli, P.; Negrello, M.; Notari, A.; Noviello, F.; Oppizzi, F.; O'Sullivan, C.; Pagano, L.; Paiella, A.; Pajer, E.; Paoletti, D.; Paradiso, S.; Partridge, R. B.; Patanchon, G.; Patil, S. P.; Perdereau, O.; Piacentini, F.; Piat, M.; Pisano, G.; Polastri, L.; Polenta, G.; Pollo, A.; Ponthieu, N.; Poulin, V.; Prêle, D.; Quartin, M.; Ravenni, A.; Remazeilles, M.; Renzi, A.; Ringeval, C.; Roest, D.; Roman, M.; Roukema, B. F.; Rubino-Martin, J.-A.; Salvati, L.; Scott, D.; Serjeant, S.; Signorelli, G.; Starobinsky, A. A.; Sunyaev, R.; Tan, C. Y.; Tartari, A.; Tasinato, G.; Toffolatti, L.; Tomasi, M.; Torrado, J.; Tramonte, D.; Trappe, N.; Triqueneaux, S.; Tristram, M.; Trombetti, T.; Tucci, M.; Tucker, C.; Urrestilla, J.; Väliviita, J.; Van de Weygaert, R.; Van Tent, B.; Vennin, V.; Verde, L.; Vermeulen, G.; Vielva, P.; Vittorio, N.; Voisin, F.; Wallis, C.; Wandelt, B.; Wehus, I.; Weller, J.; Young, K.; Zannoni, M.; for the CORE collaboration
Publication:
eprint arXiv:1706.04516
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Comment:
79 pages, 14 figures
Bibliographic Code:
2017arXiv170604516D

Abstract

Future observations of cosmic microwave background (CMB) polarisation have the potential to answer some of the most fundamental questions of modern physics and cosmology. In this paper, we list the requirements for a future CMB polarisation survey addressing these scientific objectives, and discuss the design drivers of the CORE space mission proposed to ESA in answer to the "M5" call for a medium-sized mission. The rationale and options, and the methodologies used to assess the mission's performance, are of interest to other future CMB mission design studies. CORE is designed as a near-ultimate CMB polarisation mission which, for optimal complementarity with ground-based observations, will perform the observations that are known to be essential to CMB polarisation scienceand cannot be obtained by any other means than a dedicated space mission.

 

Title:
Entanglement and entropy production in coupled single-mode Bose-Einstein condensates
Authors:
Lovas, Izabella; Fortágh, József; Demler, Eugene; Zaránd, Gergely
Publication:
eprint arXiv:1706.04571
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
Condensed Matter - Quantum Gases
Comment:
11 pages, 8 figures (including appendix)
Bibliographic Code:
2017arXiv170604571L

Abstract

We investigate the time evolution of the entanglement entropy of coupled single-mode Bose-Einstein condensates in a double well potential at $T=0$ temperature, by combining numerical results with analytical approximations. We find that the coherent oscillations of the condensates result in entropy oscillations on the top of a linear entropy generation at short time scales. Due to dephasing, the entropy eventually saturates to a stationary value, in spite of the lack of equilibration. We show that this long time limit of the entropy reflects the semiclassical dynamics of the system, revealing the self-trapping phase transition of the condensates at large interaction strength by a sudden entropy jump. We compare the stationary limit of the entropy to the prediction of a classical microcanonical ensemble, and find surprisingly good agreement in spite of the non-equilibrium state of the system. Our predictions should be experimentally observable on a Bose-Einstein condensate in a double well potential or on a two-component condensate with inter-state coupling.

 

Title:
Search for active-sterile neutrino mixing using neutral-current interactions in NOvA
Authors:
NOvA Collaboration; Adamson, P.; Aliaga, L.; Ambrose, D.;... Feldman, G. J.;... and 174 coauthors
Publication:
eprint arXiv:1706.04592
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
High Energy Physics - Experiment
Comment:
8 pages, 4 figures. Submitted to PRD RC
Bibliographic Code:
2017arXiv170604592N

Abstract

We report results from the first search for sterile neutrinos mixing with active neutrinos through a reduction in the rate of neutral-current interactions over a baseline of 810\,km between the NOvA detectors. Analyzing a 14-kton detector equivalent exposure of 6.05$\times$10$^{20}$ protons-on-target in the NuMI beam at Fermilab, we observe 95 neutral-current candidates at the Far Detector compared with $83.5 \pm 9.7 \mbox{(stat.)} \pm 9.4 \mbox{(syst.)}$ events predicted assuming mixing only occurs between active neutrino species. No evidence for $\nu_{\mu} \rightarrow \nu_{s}$ transitions is found. Interpreting these results within a 3+1 model, we place constraints on the mixing angles $\theta_{24}<20.8^{\circ}$ and $\theta_{34}<31.2^{\circ}$ at the 90% C.L. for $0.05~eV^2\leq \Delta m^2_{41}\leq 0.5~eV^2$, the range of mass splittings that produce no significant oscillations over the Near Detector baseline.

 

Title:
Probing the small-scale structure in strongly lensed systems via transdimensional inference
Authors:
Daylan, Tansu; Cyr-Racine, Francis-Yan; Diaz Rivero, Ana; Dvorkin, Cora; Finkbeiner, Douglas P.
Publication:
eprint arXiv:1706.06111
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Phenomenology
Bibliographic Code:
2017arXiv170606111D

Abstract

Strong lensing is a sensitive probe of the small-scale density fluctuations in the Universe. We implement a novel approach to modeling strongly lensed systems using probabilistic cataloging, which is a transdimensional, hierarchical, and Bayesian framework to sample from a metamodel (union of models with different dimensionality) consistent with observed photon count maps. Probabilistic cataloging allows us to robustly characterize modeling covariances within and across lens models with different numbers of subhalos. Unlike traditional cataloging of subhalos, it does not require model subhalos to improve the goodness of fit above the detection threshold. Instead, it allows the exploitation of all information contained in the photon count maps, for instance, when constraining the subhalo mass function. We further show that, by not including these small subhalos in the lens model, fixed-dimensional inference methods can significantly mismodel the data. Using a simulated Hubble Space Telescope (HST) dataset, we show that the subhalo mass function can be probed even when many subhalos in the sample catalogs are individually below the detection threshold and would be absent in a traditional catalog. With the planned Wide Field Infrared Space Telescope (WFIRST), simultaneous probabilistic cataloging of dark subhalos in high-resolution, deep strong lens images has the potential to constrain the subhalo mass function at even lower masses.

 

Title:
Black Hole Information Revisited
Authors:
Strominger, Andrew
Publication:
eprint arXiv:1706.07143
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
High Energy Physics - Theory, General Relativity and Quantum Cosmology, Mathematical Physics
Comment:
10 pages
Bibliographic Code:
2017arXiv170607143S

Abstract

We argue that four-dimensional black hole evaporation inevitably produces an infinite number of soft particles in addition to the thermally distributed `hard' Hawking quanta, and moreover that the soft and hard particles are highly correlated. This raises the possibility that quantum purity is restored by correlations between the hard and soft radiation, while inclusive measurements which omit the soft radiation observe the thermal Hawking spectrum. In theories whose only stable particle is the graviton, conservation laws are used to argue that such correlations are in principle sufficient for the soft gravitons to purify the hard thermal ones.

 

Title:
Quantum quench of the Sachdev-Ye-Kitaev Model
Authors:
Eberlein, Andreas; Kasper, Valentin; Sachdev, Subir; Steinberg, Julia
Publication:
eprint arXiv:1706.07803
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
Condensed Matter - Strongly Correlated Electrons, High Energy Physics - Theory
Comment:
33 pages, 9 figures
Bibliographic Code:
2017arXiv170607803E

Abstract

We describe the non-equilibrium dynamics of the Sachdev-Ye-Kitaev models of fermions with all-to-all interactions. These provide tractable models of the dynamics of quantum systems without quasiparticle excitations. The Kadanoff-Baym equations show that the final state is thermal, and their numerical analysis appears consistent with a thermalization rate proportional to the absolute temperature of the final state. We also obtain an exact analytic solution of the non-equilibrium dynamics in the large $q$ limit of a model with $q$ fermion interactions: in this limit, the thermalization is instantaneous.

 

Title:
Inflationary Features and Shifts in Cosmological Parameters from Planck 2015 Data
Authors:
Obied, Georges; Dvorkin, Cora; Heinrich, Chen; Hu, Wayne; Miranda, Vinicius
Publication:
eprint arXiv:1706.09412
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Phenomenology
Comment:
14 pages, 16 figures, 4 tables
Bibliographic Code:
2017arXiv170609412O

Abstract

We explore the relationship between features in the Planck 2015 temperature and polarization data, shifts in the cosmological parameters, and features from inflation. Residuals in the temperature data at low multipole $\ell$, which are responsible for the high $H_0\approx 70$ km s$^{-1}$Mpc$^{-1}$ and low $\sigma_8\Omega_m^{1/2}$ values from $\ell<1000$ in power-law $\Lambda$CDM models, are better fit to inflationary features with a $1.9\sigma$ preference for running of the running of the tilt or a stronger $99\%$ CL local significance preference for a sharp drop in power around $k=0.004$ Mpc$^{-1}$ in generalized slow roll and a lower $H_0\approx 67$ km s$^{-1}$Mpc$^{-1}$. The same in-phase acoustic residuals at $\ell>1000$ that drive the global $H_0$ constraints and appear as a lensing anomaly also favor running parameters which allow even lower $H_0$, but not once lensing reconstruction is considered. Polarization spectra are intrinsically highly sensitive to these parameter shifts, and even more so in the Planck 2015 TE data due to an outlier at $\ell \approx 165$, which disfavors the best fit $H_0$ $\Lambda$CDM solution by more than $2\sigma$, and high $H_0$ value at almost $3\sigma$. Current polarization data also slightly enhance the significance of a sharp suppression of large-scale power but leave room for large improvements in the future with cosmic variance limited $E$-mode measurements.

 

Title:
New Scanning Diamond NV Center Probes Compatible with Conventional AFM Technology
Authors:
Zhou, Tony X.; Stöhr, Rainer J.; Yacoby, Amir
Publication:
eprint arXiv:1706.09793
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Applied Physics
Comment:
15 pages, 4 figures
Bibliographic Code:
2017arXiv170609793Z

Abstract

Scanning probe microscopy using nitrogen vacancy (NV) centers in diamond has become a versatile tool with applications in physics, chemistry, life sciences and earth and planetary sciences. However, the fabrication of diamond scanning probes with high photon collection efficiency, NV centers with long coherence times and integrated radio frequency (RF) remains challenging due to the small physical dimensions of the probes and the complexity of the fabrication techniques. In this work, we present a simple and robust method to reliably fabricate probes that can be integrated with conventional qPlus sensors as well as commercial silicon AFM cantilevers. For the first time, an integrated RF micro-antenna for NV center spin manipulation is directly fabricated onto the probe making the design versatile and compatible with virtually all AFM instruments. This integration marks a complete sensor package for NV center-based magnetometry, and opens up this newly developed scanning probe technique to the broader scientific community.

 

Title:
Topological Chern-Simons/Matter Theories
Authors:
Aganagic, Mina; Costello, Kevin; McNamara, Jacob; Vafa, Cumrun
Publication:
eprint arXiv:1706.09977
Publication Date:
06/2017
Origin:
ARXIV
Keywords:
High Energy Physics - Theory, Mathematics - Algebraic Geometry, Mathematics - Differential Geometry, Mathematics - Symplectic Geometry
Comment:
50 pages, 1 figure
Bibliographic Code:
2017arXiv170609977A

Abstract

We propose a new partially topological theory in three dimensions which couples Chern-Simons theory to matter. The 3-manifolds needed for this construction admit transverse holomorphic foliation (THF). The theory depends only on the choice of such a structure, but not on a choice of metric and in this sense, it is topological. We argue that this theory arises in topological A-model string theory on Lagrangian 3-branes in the presence of additional parallel coisotropic 5-branes. The theory obtained in this way is equivalent to an N=2 supersymmetric Chern-Simons matter theory on the same 3-manifold, which also only depends on the THF structure. The theory is a realization of a topological theory of class H, which allows splitting of a temporal direction from spatial directions. We briefly discuss potential condensed matter applications.

 

Title:
Precision measurement and interpretation of inclusive W^+, W^- and Z/γ ^* production cross sections with the ATLAS detector
Authors:
Aaboud, M.; Aad, G.; Abbott, B.; Abdallah, J.;... Franklin, M.;... Huth, J.;... Morii, M.;...; and 2852 coauthors
Publication:
The European Physical Journal C, Volume 77, Issue 6, article id. #367, 62 pp. (EPJC Homepage)
Publication Date:
06/2017
Origin:
SPRINGER
Abstract Copyright:
(c) 2017: CERN for the benefit of the ATLAS collaboration
DOI:
10.1140/epjc/s10052-017-4911-9
Bibliographic Code:
2017EPJC...77..367A

Abstract

High-precision measurements by the ATLAS Collaboration are presented of inclusive W^+ → ℓ ^+ν , W^- → ℓ ^-\bar{ν } and Z/γ ^* → ℓ ℓ (ℓ =e,μ ) Drell-Yan production cross sections at the LHC. The data were collected in proton-proton collisions at √{s} = 7 {TeV} with an integrated luminosity of 4.6 fb^{-1}. Differential W^+ and W^- cross sections are measured in a lepton pseudorapidity range |η _{ℓ }|<2.5. Differential Z/γ ^* cross sections are measured as a function of the absolute dilepton rapidity, for |y_{ℓ ℓ }| < 3.6, for three intervals of dilepton mass, m_{ℓ ℓ }, extending from 46 to 150 {GeV}. The integrated and differential electron- and muon-channel cross sections are combined and compared to theoretical predictions using recent sets of parton distribution functions. The data, together with the final inclusive e^{± }p scattering cross-section data from H1 and ZEUS, are interpreted in a next-to-next-to-leading-order QCD analysis, and a new set of parton distribution functions, ATLAS-epWZ16, is obtained. The ratio of strange-to-light sea-quark densities in the proton is determined more accurately than in previous determinations based on collider data only, and is established to be close to unity in the sensitivity range of the data. A new measurement of the CKM matrix element \vert V_{cs} \vert is also provided.

 

Title:
Measurement of jet fragmentation in Pb+Pb and pp collisions at √{{s_NN}} = 2.76 TeV with the ATLAS detector at the LHC
Authors:
Aaboud, M.; Aad, G.; Abbott, B.; Abdallah, J.;... Franklin, M.;... Huth, J.;... Morii, M.;...; and 2852 coauthors
Publication:
The European Physical Journal C, Volume 77, Issue 6, article id. #379, 29 pp. (EPJC Homepage)
Publication Date:
06/2017
Origin:
SPRINGER
Abstract Copyright:
(c) 2017: CERN for the benefit of the ATLAS collaboration
DOI:
10.1140/epjc/s10052-017-4915-5
Bibliographic Code:
2017EPJC...77..379A

Abstract

The distributions of transverse momentum and longitudinal momentum fraction of charged particles in jets are measured in Pb+Pb and pp collisions with the ATLAS detector at the LHC. The distributions are measured as a function of jet transverse momentum and rapidity. The analysis utilises an integrated luminosity of 0.14 nb^{-1} of Pb+Pb data and 4.0 pb^{-1} of pp data collected in 2011 and 2013, respectively, at the same centre-of-mass energy of 2.76 TeV per colliding nucleon pair. The distributions measured in pp collisions are used as a reference for those measured in Pb+Pb collisions in order to evaluate the impact on the internal structure of jets from the jet energy loss of fast partons propagating through the hot, dense medium created in heavy-ion collisions. Modest but significant centrality-dependent modifications of fragmentation functions in Pb+Pb collisions with respect to those in pp collisions are seen. No significant dependence of modifications on jet p_T and rapidity selections is observed except for the fragments with the highest transverse momenta for which some reduction of yields is observed for more forward jets.

 

Title:
Search for dark matter at √{s}=13 TeV in final states containing an energetic photon and large missing transverse momentum with the ATLAS detector
Authors:
Aaboud, M.; Aad, G.; Abbott, B.; Abdallah, J.;... Franklin, M.;... Huth, J.;... Morii, M.;...; and 2851 coauthors
Publication:
The European Physical Journal C, Volume 77, Issue 6, article id. #393, 30 pp. (EPJC Homepage)
Publication Date:
06/2017
Origin:
SPRINGER
Abstract Copyright:
(c) 2017: CERN for the benefit of the ATLAS collaboration
DOI:
10.1140/epjc/s10052-017-4965-8
Bibliographic Code:
2017EPJC...77..393A

Abstract

Results of a search for physics beyond the Standard Model in events containing an energetic photon and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. As the number of events observed in data, corresponding to an integrated luminosity of 36.1 fb^{-1} of proton-proton collisions at a centre-of-mass energy of 13 TeV, is in agreement with the Standard Model expectations, model-independent limits are set on the fiducial cross section for the production of events in this final state. Exclusion limits are also placed in models where dark-matter candidates are pair-produced. For dark-matter production via an axial-vector or a vector mediator in the s-channel, this search excludes mediator masses below 750-1200 GeV for dark-matter candidate masses below 230-480 GeV at 95% confidence level, depending on the couplings. In an effective theory of dark-matter production, the limits restrict the value of the suppression scale M_{*} to be above 790 GeV at 95% confidence level. A limit is also reported on the production of a high-mass scalar resonance by processes beyond the Standard Model, in which the resonance decays to Zγ and the Z boson subsequently decays into neutrinos.

 

Title:
Effect of nanoscale flows on the surface structure of nanoporous catalysts
Authors:
Montemore, Matthew M.; Montessori, Andrea; Succi, Sauro; Barroo, Cédric; Falcucci, Giacomo; Bell, David C.; Kaxiras, Efthimios
Publication:
The Journal of Chemical Physics, Volume 146, Issue 21, id.214703 (JChPh Homepage)
Publication Date:
06/2017
Origin:
AIP
Abstract Copyright:
2017: Author(s)
DOI:
10.1063/1.4984614
Bibliographic Code:
2017JChPh.146u4703M

Abstract

The surface structure and composition of a multi-component catalyst are critical factors in determining its catalytic performance. The surface composition can depend on the local pressure of the reacting species, leading to the possibility that the flow through a nanoporous catalyst can affect its structure and reactivity. Here, we explore this possibility for oxidation reactions on nanoporous gold, an AgAu bimetallic catalyst. We use microscopy and digital reconstruction to obtain the morphology of a two-dimensional slice of a nanoporous gold sample. Using lattice Boltzmann fluid dynamics simulations along with thermodynamic models based on first-principles total-energy calculations, we show that some sections of this sample have low local O2 partial pressures when exposed to reaction conditions, which leads to a pure Au surface in these regions, instead of the active bimetallic AgAu phase. We also explore the effect of temperature on the surface structure and find that moderate temperatures (≈300-450 K) should result in the highest intrinsic catalytic performance, in apparent agreement with experimental results.

 

Title:
Deciphering the MSSM Higgs mass at future hadron colliders
Authors:
Agrawal, Prateek; Fan, JiJi; Reece, Matthew; Xue, Wei
Publication:
Journal of High Energy Physics, Volume 2017, Issue 6, article id. #27, 31 pp.
Publication Date:
06/2017
Origin:
SPRINGER
Keywords:
Supersymmetry Phenomenology
Abstract Copyright:
(c) 2017: The Author(s)
DOI:
10.1007/JHEP06(2017)027
Bibliographic Code:
2017JHEP...06..027A

Abstract

Future hadron colliders will have a remarkable capacity to discover massive new particles, but their capabilities for precision measurements of couplings that can reveal underlying mechanisms have received less study. In this work we study the capability of future hadron colliders to shed light on a precise, focused question: is the higgs mass of 125 GeV explained by the MSSM? If supersymmetry is realized near the TeV scale, a future hadron collider could produce huge numbers of gluinos and electroweakinos. We explore whether precision measurements of their properties could allow inference of the scalar masses and tan β with sufficient accuracy to test whether physics beyond the MSSM is needed to explain the higgs mass. We also discuss dark matter direct detection and precision higgs physics as complementary probes of tan β. For concreteness, we focus on the mini-split regime of MSSM parameter space at a 100 TeV pp collider, with scalar masses ranging from 10s to about 1000 TeV.

 

Title:
Extracting loss from asymmetric resonances in micro-ring resonators
Authors:
Reshef, O.; Moebius, M. G.; Mazur, E.
Publication:
Journal of Optics, Volume 19, Issue 6, article id. 065804 (2017).
Publication Date:
06/2017
Origin:
IOP
DOI:
10.1088/2040-8986/aa7006
Bibliographic Code:
2017JOpt...19f5804R

Abstract

Propagation losses in micro-ring resonator waveguides can be determined from the shape of individual resonances in their transmission spectrum. The losses are typically extracted by fitting these resonances to an idealized model that is derived using scattering theory. Reflections caused by waveguide boundaries or stitching errors, however, cause the resonances to become asymmetric, resulting in poor fits and unreliable propagation loss coefficients. We derive a model that takes reflections into account and, by performing full-wave simulations, we show that this model accurately describes the asymmetric resonances that result from purely linear effects, yielding accurate propagation loss coefficients.

 

Title:
Universal dynamical phase diagram of lattice spin models and strongly correlated ultracold atoms in optical lattices
Authors:
Demler, E. A.; Maltsev, A. Ya; Prokofiev, A. O.
Publication:
Journal of Physics B: Atomic, Molecular, and Optical Physics, Volume 50, Issue 12, article id. 124001 (2017).
Publication Date:
06/2017
Origin:
IOP
DOI:
10.1088/1361-6455/50/12/124001
Bibliographic Code:
2017JPhB...50l4001D

Abstract

We study semiclassical dynamics of anisotropic Heisenberg models in two and three dimensions. Such models describe lattice spin systems and hard core bosons in optical lattices. We solve numerically Landau–Lifshitz type equations on a lattice and show that in the phase diagram of magnetization and interaction anisotropy, one can identify several distinct regimes of dynamics. These regions can be distinguished based on the character of one dimensional solitonic excitations, and stability of such solitons to transverse modulation. Small amplitude and long wavelength perturbations can be analyzed analytically using mapping of non-linear hydrodynamic equations to KdV type equations. Numerically we find that properties of solitons and dynamics in general remain similar to our analytical results even for large amplitude and short distance inhomogeneities, which allows us to obtain a universal dynamical phase diagram. As a concrete example we study dynamical evolution of the system starting from a state with magnetization step and show that formation of oscillatory regions and their stability to transverse modulation can be understood from the properties of solitons. In regimes unstable to transverse modulation we observe formation of lump type solutions with modulation in all directions. We discuss implications of our results for experiments with ultracold atoms.

 

Title:
Quantum Nonlinear Optics with a Germanium-Vacancy Color Center in a Nanoscale Diamond Waveguide
Authors:
Bhaskar, M. K.; Sukachev, D. D.; Sipahigil, A.; Evans, R. E.; Burek, M. J.; Nguyen, C. T.; Rogers, L. J.; Siyushev, P.; Metsch, M. H.; Park, H.; Jelezko, F.; Lončar, M.; Lukin, M. D.
Publication:
Physical Review Letters, Volume 118, Issue 22, id.223603 (PhRvL Homepage)
Publication Date:
06/2017
Origin:
APS
Abstract Copyright:
2017: American Physical Society
DOI:
10.1103/PhysRevLett.118.223603
Bibliographic Code:
2017PhRvL.118v3603B

Abstract

We demonstrate a quantum nanophotonics platform based on germanium-vacancy (GeV) color centers in fiber-coupled diamond nanophotonic waveguides. We show that GeV optical transitions have a high quantum efficiency and are nearly lifetime broadened in such nanophotonic structures. These properties yield an efficient interface between waveguide photons and a single GeV center without the use of a cavity or slow-light waveguide. As a result, a single GeV center reduces waveguide transmission by 18 ±1 % on resonance in a single pass. We use a nanophotonic interferometer to perform homodyne detection of GeV resonance fluorescence. By probing the photon statistics of the output field, we demonstrate that the GeV-waveguide system is nonlinear at the single-photon level.

 

Title:
Constraints on Oscillation Parameters from νe Appearance and νμ Disappearance in NOvA
Authors:
Adamson, P.; Aliaga, L.; Ambrose, D.;... Feldman, G. J.;...; and 177 coauthors, NOvA Collaboration
Publication:
Physical Review Letters, Volume 118, Issue 23, id.231801 (PhRvL Homepage)
Publication Date:
06/2017
Origin:
APS
Abstract Copyright:
2017: American Physical Society
DOI:
10.1103/PhysRevLett.118.231801
Bibliographic Code:
2017PhRvL.118w1801A

Abstract

Results are reported from an improved measurement of νμ→νe transitions by the NOvA experiment. Using an exposure equivalent to 6.05 ×1 020 protons on target, 33 νe candidates are observed with a background of 8.2 ±0.8 (syst.). Combined with the latest NOvA νμ disappearance data and external constraints from reactor experiments on sin22 θ13, the hypothesis of inverted mass hierarchy with θ23 in the lower octant is disfavored at greater than 93% C.L. for all values of δC P.

 

Title:
Peer Instruction in introductory physics: A method to bring about positive changes in students' attitudes and beliefs
Authors:
Zhang, Ping; Ding, Lin; Mazur, Eric
Publication:
Physical Review Physics Education Research, Volume 13, Issue 1, id.010104
Publication Date:
06/2017
Origin:
APS; AIP
Abstract Copyright:
2017: authors
DOI:
10.1103/PhysRevPhysEducRes.13.010104
Bibliographic Code:
2017PRPER..13a0104Z

Abstract

This paper analyzes pre-post matched gains in the epistemological views of science students taking the introductory physics course at Beijing Normal University (BNU) in China. In this study we examined the attitudes and beliefs of science majors (n =441 ) in four classes, one taught using traditional (lecture) teaching methods, and the other three taught with Peer Instruction (PI). In two of the PI classes, student peer groups were constantly changing throughout the semester, while in the other PI class student groups remained fixed for the duration of the semester. The results of the pre- and post-test using the Colorado Learning Attitudes about Science Survey showed that students in traditional lecture settings became significantly more novicelike in their beliefs about physics and learning physics over the course of a semester, a result consistent with what was reported in the literature. However, all three of the classes taught using the PI method improved student attitudes and beliefs about physics and learning physics. In the PI class with fixed peer groups, students exhibited a greater positive shift in attitudes and beliefs than in the other PI class with changing peer groups. The study also looked at gender differences in student learning attitudes. Gender results revealed that female science majors in the PI classes achieved a greater positive shift in attitudes and beliefs after instruction than did male students.

 

Title:
Publisher's Note: Peer Instruction in introductory physics: A method to bring about positive changes in students' attitudes and beliefs [Phys. Rev. Phys. Educ. Res. 13, 010104 (2017)]
Authors:
Zhang, Ping; Ding, Lin; Mazur, Eric
Publication:
Physical Review Physics Education Research, Volume 13, Issue 1, id.019904
Publication Date:
06/2017
Origin:
APS
DOI:
10.1103/PhysRevPhysEducRes.13.019904
Bibliographic Code:
2017PRPER..13a9904Z

Abstract

Not Available

 


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