## Faculty Publications: September, 2010

Query Results from the Smithsonian/NASA Astrophysics Data System (ADS)

 Title: Field fluctuations measured by interferometry Authors: Glauber, R. J.; Orozco, L. A.; Vogel, K.; Schleich, W. P.; Walther, H. Publication: Physica Scripta, Volume 140, Issue , pp. 014002 (2010). Publication Date: 09/2010 Origin: IOP DOI: 10.1088/0031-8949/2010/T140/014002 Bibliographic Code: 2010PhST..140a4002G

### Abstract

We derive the complete photon count statistics of an interferometer based on two beam splitters. As a special case we consider a joint intensity–electric field measurement. Our approach is based on the transformation properties of state vectors as well as field operators at a beam splitter.

The work presented here was stimulated by discussions during the Lake Garda Conference 2001. The recent experimental interest in six-port interferometry has moved us to return to the problem. We feel, moreover, that the topic is appropriate for the Festschrift in honour of Stig Stenholm since he can truly be considered a pioneer in the field of quantum networks. We hope that our discussion may pique his interest.

 Title: Search for New Physics with a Dijet Plus Missing ET Signature in p&pmacr; Collisions at s=1.96TeV Authors: Aaltonen, T.; Adelman, J.; Álvarez González, B.;... Franklin, M.; ... Guimaraes da Costa, J....; and 572 coauthors. Publication: Physical Review Letters, vol. 105, Issue 10, id. 101801 (PhRvL Homepage) Publication Date: 09/2010 Origin: APS PACS Keywords: Applications of electroweak models to specific processes, Top quarks Abstract Copyright: (c) : DOI: 10.1103/PhysRevLett.105.101801 Bibliographic Code: 2010PhRvL.105j1801A

### Abstract

We present results of a signature-based search for new physics using a dijet plus missing transverse energy (ET) data sample collected in 2.7fb-1 of p&pmacr; collisions at s=1.96TeV with the CDF II detector at the Fermilab Tevatron. We observe no significant event excess with respect to the standard model prediction and extract a 95% C.L. upper limit on the cross section times acceptance for a potential contribution from a nonstandard model process. The search is made by using novel, data-driven techniques for estimating backgrounds that are applicable to first searches at the LHC.

 Title: Evidence for Direct CP Violation in the Measurement of the Cabbibo-Kobayashi-Maskawa Angle γ with B∓→D(*)K(*)∓ Decays Authors: Del Amo Sanchez, P.; Lees, J. P.; Poireau, V.; ... Morii, M.;...; and 444 coauthors. Publication: Physical Review Letters, vol. 105, Issue 12, id. 121801 (PhRvL Homepage) Publication Date: 09/2010 Origin: APS PACS Keywords: Determination of Kobayashi-Maskawa matrix elements, Charge conjugation, parity, time reversal, and other discrete symmetries, Decays of charmed mesons, Decays of bottom mesons Abstract Copyright: (c) : DOI: 10.1103/PhysRevLett.105.121801 Bibliographic Code: 2010PhRvL.105l1801D

### Abstract

We report the measurement of the Cabibbo-Kobayashi-Maskawa CP-violating angle γ through a Dalitz plot analysis of neutral D-meson decays to KS0π+π- and KS0K+K- produced in the processes B→DK, B→D*K with D*→Dπ0, Dγ, and B→DK*∓ with K*∓→KS0π, using 468 million B&Bmacr; pairs collected by the BABAR detector at the PEP-II asymmetric-energy e+e- collider at SLAC. We measure γ=(68±14±4±3)° (modulo 180°), where the first error is statistical, the second is the experimental systematic uncertainty, and the third reflects the uncertainty in the description of the neutral D decay amplitudes. This result is inconsistent with γ=0 (no direct CP violation) with a significance of 3.5 standard deviations.

 Title: Exclusion of an Exotic Top Quark with -4/3 Electric Charge Using Soft Lepton Tagging Authors: Aaltonen, T.; Adelman, J.; Álvarez González, B.;... Franklin, M.; ... Guimaraes da Costa, J....; and 572 coauthors. Publication: Physical Review Letters, vol. 105, Issue 10, id. 101801 (PhRvL Homepage) Publication Date: 09/2010 Origin: APS PACS Keywords: Applications of electroweak models to specific processes, Top quarks Abstract Copyright: (c) : DOI: 10.1103/PhysRevLett.105.101801 Bibliographic Code: 2010PhRvL.105j1801A

### Abstract

We present a measurement of the electric charge of the top quark using p&pmacr; collisions corresponding to an integrated luminosity of 2.7fb-1 at the CDF II detector. We reconstruct t&tmacr; events in the lepton+jets final state. We use soft lepton taggers to determine the flavor of the b jets, which we use to reconstruct the top quark’s electric charge and exclude an exotic top quark with -4/3 charge at 95% confidence level. This is the strongest exclusion of the exotic charge scenario and the first to use soft leptons for this purpose.

 Title: Search for anomalous production of events with two photons and additional energetic objects at CDF Authors: Aaltonen, T.; Adelman, J.; Álvarez González, B.;... Franklin, M.; ... Guimaraes da Costa, J....; and 570 coauthors. Publication: Physical Review D, vol. 82, Issue 5, id. 052005 (PhRvD Homepage) Publication Date: 09/2010 Origin: APS PACS Keywords: Limits on production of particles, Inclusive production with identified leptons, photons, or other nonhadronic particles, Supersymmetric partners of known particles DOI: 10.1103/PhysRevD.82.052005 Bibliographic Code: 2010PhRvD..82e2005A

### Abstract

We present results of a search for anomalous production of two photons together with an electron, muon, τ lepton, missing transverse energy, or jets using p&pmacr; collision data from 1.1–2.0fb-1 of integrated luminosity collected by the Collider Detector at Fermilab (CDF). The event yields and kinematic distributions are examined for signs of new physics without favoring a specific model of new physics. The results are consistent with the standard model expectations. The search employs several new analysis techniques that significantly reduce instrumental backgrounds in channels with an electron and missing transverse energy.

 Title: Exclusive production of Ds+Ds-, Ds*+Ds-, and Ds*+Ds*- via e+e- annihilation with initial-state radiation Authors: Del Amo Sanchez, P.; Lees, J. P.; Poireau, V.; ... Morii, M.;...; and 438 coauthors. Publication: Physical Review D, vol. 82, Issue 5, id. 052004 (PhRvD Homepage) Publication Date: 09/2010 Origin: APS PACS Keywords: Decays of J/psi, Upsilon, and other quarkonia, Hadron production in e-e+ interactions DOI: 10.1103/PhysRevD.82.052004 Bibliographic Code: 2010PhRvD..82e2004D

### Abstract

We perform a study of exclusive production of Ds+Ds-, Ds*+Ds-, and Ds*+Ds*- final states in initial-state-radiation events from e+e- annihilations at a center-of-mass energy near 10.58 GeV, to search for charmonium 1-- states. The data sample corresponds to an integrated luminosity of 525fb-1 and was recorded by the BABAR experiment at the PEP-II storage ring. The Ds+Ds-, Ds*+Ds-, and Ds*+Ds*- mass spectra show evidence of the known ψ resonances. Limits are extracted for the branching ratios of the decays X(4260)→Ds(*)+Ds(*)-.

 Title: Measurement of the top pair production cross section in the dilepton decay channel in p&pmacr; collisions at s=1.96TeV Authors: Aaltonen, T.; Álvarez González, B.;... Franklin, M.; ... Guimaraes da Costa, J....; and 510 coauthors. Publication: Physical Review D, vol. 82, Issue 5, id. 052002 (PhRvD Homepage) Publication Date: 09/2010 Origin: APS PACS Keywords: Top quarks, Experimental tests, Inclusive production with identified leptons, photons, or other nonhadronic particles DOI: 10.1103/PhysRevD.82.052002 Bibliographic Code: 2010PhRvD..82e2002A

### Abstract

A measurement of the t&tmacr; production cross section in p&pmacr; collisions at s=1.96TeV using events with two leptons, missing transverse energy, and jets is reported. The data were collected with the CDF II detector. The result in a data sample corresponding to an integrated luminosity 2.8fb-1 is σt&tmacr;=6.27±0.73(stat)±0.63(syst)±0.39(lum)pb. for an assumed top mass of 175GeV/c2.

 Title: New constraints on muon-neutrino to electron-neutrino transitions in MINOS Authors: Adamson, P.; Andreopoulos, C.; Auty, D. J.;... Feldman, G. J.;... and 140 coauthors. Publication: Physical Review D, vol. 82, Issue 5, id. 051102 (PhRvD Homepage) Publication Date: 09/2010 Origin: APS PACS Keywords: Neutrino mass and mixing, Ordinary neutrinos (nuW bosons, Beams in particle accelerators Abstract Copyright: (c) : DOI: 10.1103/PhysRevD.82.051102 Bibliographic Code: 2010PhRvD..82e1102A

### Abstract

Using a sample of 471×106 B&Bmacr; events collected with the BABAR detector, we study the sum of seven exclusive final states B→Xs(d)γ, where Xs(d) is a strange (nonstrange) hadronic system with a mass of up to 2.0GeV/c2. After correcting for unobserved decay modes, we obtain a branching fraction for b→dγ of (9.2±2.0(stat)±2.3(syst))×10-6 in this mass range, and a branching fraction for b→sγ of (23.0±0.8(stat)±3.0(syst))×10-5 in the same mass range. We find (B(b→dγ))/(B(b→sγ))=0.040±0.009(stat)±0.010(syst), from which we determine |Vtd/Vts|=0.199±0.022(stat)±0.024(syst)±0.002(th).

 Title: Study of B→Xγ decays and determination of |Vtd/Vts| Authors: Del Amo Sanchez, P.; Lees, J. P.; Poireau, V.; ... Morii, M.;...; and 441 coauthors. Publication: Physical Review D, vol. 82, Issue 5, id. 051101 (PhRvD Homepage) Publication Date: 09/2010 Origin: APS PACS Keywords: Bottom mesons, Determination of Kobayashi-Maskawa matrix elements Abstract Copyright: (c) : DOI: 10.1103/PhysRevD.82.051101 Bibliographic Code: 2010PhRvD..82e1101D

### Abstract

Using a sample of 471×106 B&Bmacr; events collected with the BABAR detector, we study the sum of seven exclusive final states B→Xs(d)γ, where Xs(d) is a strange (nonstrange) hadronic system with a mass of up to 2.0GeV/c2. After correcting for unobserved decay modes, we obtain a branching fraction for b→dγ of (9.2±2.0(stat)±2.3(syst))×10-6 in this mass range, and a branching fraction for b→sγ of (23.0±0.8(stat)±3.0(syst))×10-5 in the same mass range. We find (B(b→dγ))/(B(b→sγ))=0.040±0.009(stat)±0.010(syst), from which we determine |Vtd/Vts|=0.199±0.022(stat)±0.024(syst)±0.002(th).

 Title: Double quantum dots in carbon nanotubes Authors: von Stecher, J.; Wunsch, B.; Lukin, M.; Demler, E.; Rey, A. M. Publication: Physical Review B, vol. 82, Issue 12, id. 125437 (PhRvB Homepage) Publication Date: 09/2010 Origin: APS PACS Keywords: Nanotubes, Electronic transport in mesoscopic systems, Electronic structure of nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals Abstract Copyright: (c) 2010: The American Physical Society DOI: 10.1103/PhysRevB.82.125437 Bibliographic Code: 2010PhRvB..82l5437V

### Abstract

We study the two-electron eigenspectrum of a carbon-nanotube double quantum dot with spin-orbit coupling. Exact calculations are combined with a simple model to provide an intuitive and accurate description of single-particle and interaction effects. For symmetric dots and weak magnetic fields, the two-electron ground state is antisymmetric in the spin-valley degree of freedom and is not a pure spin-singlet state. When double occupation of one dot is favored by increasing the detuning between the dots, the Coulomb interaction causes strong correlation effects realized by higher orbital-level mixing. Changes in the double-dot configuration affect the relative strength of the electron-electron interactions and can lead to different ground-state transitions. In particular, they can favor a ferromagnetic ground state both in spin and valley degrees of freedom. The strong suppression of the energy gap can cause the disappearance of the Pauli blockade in transport experiments and thereby can also limit the stability of spin qubits in quantum information proposals. Our analysis is generalized to an array of coupled dots which is expected to exhibit rich many-body behavior.

 Title: Scattering-assisted tunneling: Energy dependence, magnetic field dependence, and use as an external probe of two-dimensional transport Authors: Russell, K. J.; Capasso, F.; Narayanamurti, V.; Lu, H.; Zide, J. M. O.; Gossard, A. C. Publication: Physical Review B, vol. 82, Issue 11, id. 115322 (PhRvB Homepage) Publication Date: 09/2010 Origin: APS PACS Keywords: Tunneling, Novel experimental methods; measurements, Tunneling, Quantum wells Abstract Copyright: (c) 2010: The American Physical Society DOI: 10.1103/PhysRevB.82.115322 Bibliographic Code: 2010PhRvB..82k5322R

### Abstract

For more than three decades, research on tunneling through planar barriers has focused principally on processes that conserve momentum parallel to the barrier. Here we investigate transport in which scattering destroys lateral momentum conservation and greatly enhances the tunneling probability. We have measured its energy dependence using capacitance spectroscopy, and we show that for electrons confined in a quantum well, the scattering enhancement can be quenched in an applied magnetic field, enabling this mechanism to function as an external probe of the origin of the quantum Hall effect.

 Title: Quantum critical point shifts under superconductivity: Pnictides and cuprates Authors: Moon, Eun Gook; Sachdev, Subir Publication: Physical Review B, vol. 82, Issue 10, id. 104516 (PhRvB Homepage) Publication Date: 09/2010 Origin: APS PACS Keywords: Superconductivity phase diagrams, Quantized spin models Abstract Copyright: (c) 2010: The American Physical Society DOI: 10.1103/PhysRevB.82.104516 Bibliographic Code: 2010PhRvB..82j4516M

### Abstract

We compare the position of an ordering transition in a metal to that in a superconductor. For the spin-density wave (SDW) transition, we find that the quantum critical point shifts by order |Δ| , where Δ is pairing amplitude so that the region of SDW order is smaller in the superconductor than in the metal. This shift is larger than the ˜|Δ|2 shift predicted by theories of competing orders which ignore Fermi-surface effects. For Ising-nematic order, the shift from Fermi-surface effects remains of order |Δ|2 . We discuss implications of these results for the phase diagrams of the cuprates and the pnictides. We conclude that recent observations imply that the Ising-nematic order is tied to the square of the SDW order in the pnictides but not in the cuprates.

 Title: Exploring topological phases with quantum walks Authors: Kitagawa, Takuya; Rudner, Mark S.; Berg, Erez; Demler, Eugene Publication: Physical Review A, vol. 82, Issue 3, id. 033429 (PhRvA Homepage) Publication Date: 09/2010 Origin: APS PACS Keywords: Atoms in optical lattices, Quantum optics Abstract Copyright: (c) 2010: The American Physical Society DOI: 10.1103/PhysRevA.82.033429 Bibliographic Code: 2010PhRvA..82c3429K

### Abstract

The quantum walk was originally proposed as a quantum-mechanical analog of the classical random walk, and has since become a powerful tool in quantum information science. In this paper, we show that discrete-time quantum walks provide a versatile platform for studying topological phases, which are currently the subject of intense theoretical and experimental investigations. In particular, we demonstrate that recent experimental realizations of quantum walks with cold atoms, photons, and ions simulate a nontrivial one-dimensional topological phase. With simple modifications, the quantum walk can be engineered to realize all of the topological phases, which have been classified in one and two dimensions. We further discuss the existence of robust edge modes at phase boundaries, which provide experimental signatures for the nontrivial topological character of the system.

 Title: Measurement of dσ/dy of Drell-Yan e+e‑ pairs in the Z mass region from pp¯ collisions at s=1.96 TeV Authors: Cdf Collaboration; Aaltonen, T.; Adelman, J.; Álvarez González, B.;... Franklin, M.; ... Guimaraes da Costa, J....; and 571 coauthors. Publication: Physics Letters B, Volume 692, Issue 4, p. 232-239. Publication Date: 09/2010 Origin: ELSEVIER Abstract Copyright: Elsevier B.V. DOI: 10.1016/j.physletb.2010.06.043 Bibliographic Code: 2010PhLB..692..232C

### Abstract

We report on a CDF measurement of the total cross section and rapidity distribution, dσ/dy, for γ/Z→e+e events in the Z boson mass region (66<M<116 GeV/c2) produced in pp¯ collisions at s=1.96 TeV with 2.1 fb‑1 of integrated luminosity. The measured cross section of 257±16 pb and dσ/dy distribution are compared with Next-to-Leading-Order (NLO) and Next-to-Next-to-Leading-Order (NNLO) QCD theory predictions with CTEQ and MRST/MSTW parton distribution functions (PDFs). There is good agreement between the experimental total cross section and dσ/dy measurements with theoretical calculations with the most recent NNLO PDFs.

 Title: Flavor hierarchy from F-theory Authors: Heckman, Jonathan J.; Vafa, Cumrun Publication: Nuclear Physics B, Volume 837, Issue 1-2, p. 137-151. Publication Date: 09/2010 Origin: ELSEVIER Abstract Copyright: (c) 2010 Elsevier Science B.V. All rights reserved. DOI: 10.1016/j.nuclphysb.2010.05.009 Bibliographic Code: 2010NuPhB.837..137H

### Abstract

It has recently been shown that F-theory based constructions provide a potentially promising avenue for engineering GUT models which descend to the MSSM. In this Note we show that in the presence of background fluxes, these models automatically achieve hierarchical Yukawa matrices in the quark and lepton sectors. At leading order, the existence of a U(1) symmetry which is related to phase rotations of the internal holomorphic coordinates at the brane intersection point leads to rank one Yukawa matrices. Subleading corrections to the internal wave functions from variations in the background fluxes generate small violations of this U(1), leading to hierarchical Yukawa structures reminiscent of the Froggatt-Nielsen mechanism. The expansion parameter for this perturbation is in terms of α. Moreover, we naturally obtain a hierarchical CKM matrix with V˜V˜ɛ, V˜V˜ɛ2, V˜V˜ɛ3, where ɛ˜α, in excellent agreement with observation.

 Title: Graphene as a subnanometre trans-electrode membrane Authors: Garaj, S.; Hubbard, W.; Reina, A.; Kong, J.; Branton, D.; Golovchenko, J. A. Publication: Nature, Volume 467, Issue 7312, pp. 190-193 (2010). (Nature Homepage) Publication Date: 09/2010 Origin: NATURE Abstract Copyright: (c) 2010: Nature DOI: 10.1038/nature09379 Bibliographic Code: 2010Natur.467..190G

### Abstract

Isolated, atomically thin conducting membranes of graphite, called graphene, have recently been the subject of intense research with the hope that practical applications in fields ranging from electronics to energy science will emerge. The atomic thinness, stability and electrical sensitivity of graphene motivated us to investigate the potential use of graphene membranes and graphene nanopores to characterize single molecules of DNA in ionic solution. Here we show that when immersed in an ionic solution, a layer of graphene becomes a new electrochemical structure that we call a trans-electrode. The trans-electrode's unique properties are the consequence of the atomic-scale proximity of its two opposing liquid-solid interfaces together with graphene's well known in-plane conductivity. We show that several trans-electrode properties are revealed by ionic conductance measurements on a graphene membrane that separates two aqueous ionic solutions. Although our membranes are only one to two atomic layers thick, we find they are remarkable ionic insulators with a very small stable conductance that depends on the ion species in solution. Electrical measurements on graphene membranes in which a single nanopore has been drilled show that the membrane's effective insulating thickness is less than one nanometre. This small effective thickness makes graphene an ideal substrate for very high resolution, high throughput nanopore-based single-molecule detectors. The sensitivity of graphene's in-plane electronic conductivity to its immediate surface environment and trans-membrane solution potentials will offer new insights into atomic surface processes and sensor development opportunities.

 Title: Quantum Corral Resonance Widths: Lossy Scattering as Acoustics Authors: Barr, Matthew C.; Zaletel, Michael P.; Heller, Eric J. Publication: Nano Letters, vol. 10, issue 9, pp. 3253-3260 Publication Date: 09/2010 Origin: CROSSREF DOI: 10.1021/nl100569w Bibliographic Code: 2010NanoL..10.3253B

### Abstract

Not Available

 Title: F-theory and the LHC: stau search Authors: Heckman, Jonathan J.; Shao, Jing; Vafa, Cumrun Affiliation: AA(School of Natural Sciences, Institute for Advanced Study), AB(Department of Physics, Syracuse University), AC(Jefferson Physical Laboratory, Harvard University) Publication: Journal of High Energy Physics, Volume 2010, article id. #20 Publication Date: 09/2010 Origin: SPRINGER Keywords: Supersymmetry Phenomenology, Strings and branes phenomenology Abstract Copyright: (c) 2010: SISSA, Trieste, Italy DOI: 10.1007/JHEP09(2010)020 Bibliographic Code: 2010JHEP...09..020H

### Abstract

F-theory GUT models favor a relatively narrow range of soft supersymmetry breaking parameters in the MSSM Lagrangian. This leads to the specific predictions that a 10 ‑ 100 MeV mass gravitino is the LSP, and the NLSP is quasi-stable, with a lifetime between a second to an hour. In a wide range of parameter space, the NLSP turns out to be a stau, though a bino-like lightest neutralino is also possible. Focusing on F-theory GUTs with a stau NLSP, we study the discovery potential at the LHC for such scenarios. Models with a quasi-stable stau predict a striking signature of a heavy charged particle passing through the detector. As a function of the parameters of minimal F-theory GUTs, we study how many of such events to expect, and additional signatures correlated with the presence of quasi-stable staus. We also study the prospects for staus to become stopped in or near the detector, as well as potential ways to distinguish such models from minimal gauge mediation models with similar spectra.

 Title: Imaging mesoscopic nuclear spin noise with a diamond magnetometer Authors: Meriles, Carlos A.; Jiang, Liang; Goldstein, Garry; Hodges, Jonathan S.; Maze, Jeronimo; Lukin, Mikhail D.; Cappellaro, Paola Publication: Journal of Chemical Physics, Volume 133, Issue 12, pp. 124105-124105-8 (2010). (JChPh Homepage) Publication Date: 09/2010 Origin: AIP Keywords: association, biochemistry, biological NMR, biological techniques, biological tissues, diamond, magnetic sensors, nanobiotechnology, nitrogen, vacancies (crystal) PACS Keywords: NMR, Magnetic and paramagnetic resonance, Association, addition, insertion, cluster formation Abstract Copyright: (c) 2010: American Institute of Physics DOI: 10.1063/1.3483676 Bibliographic Code: 2010JChPh.133l4105M

### Abstract

Magnetic resonance imaging can characterize and discriminate among tissues using their diverse physical and biochemical properties. Unfortunately, submicrometer screening of biological specimens is presently not possible, mainly due to lack of detection sensitivity. Here we analyze the use of a nitrogen-vacancy center in diamond as a magnetic sensor for nanoscale nuclear spin imaging and spectroscopy. We examine the ability of such a sensor to probe the fluctuations of the classical'' dipolar field due to a large number of neighboring nuclear spins in a densely protonated sample. We identify detection protocols that appropriately take into account the quantum character of the sensor and find a signal-to-noise ratio compatible with realistic experimental parameters. Through various example calculations we illustrate different kinds of image contrast. In particular, we show how to exploit the comparatively long nuclear spin correlation times to reconstruct a local, high-resolution sample spectrum.

 Title: Link Homologies and the Refined Topological Vertex Authors: Gukov, Sergei; Iqbal, Amer; Kozçaz, Can; Vafa, Cumrun Publication: Communications in Mathematical Physics, Volume 298, Issue 3, pp.757-785 Publication Date: 09/2010 Origin: SPRINGER Abstract Copyright: (c) 2010: The Author(s) DOI: 10.1007/s00220-010-1045-4 Bibliographic Code: 2010CMaPh.298..757G

### Abstract

We establish a direct map between refined topological vertex and sl( N) homological invariants of the of Hopf link, which include Khovanov-Rozansky homology as a special case. This relation provides an exact answer for homological invariants of the Hopf link, whose components are colored by arbitrary representations of sl( N). At present, the mathematical formulation of such homological invariants is available only for the fundamental representation (the Khovanov-Rozansky theory) and the relation with the refined topological vertex should be useful for categorizing quantum group invariants associated with other representations ( R 1, R 2). Our result is a first direct verification of a series of conjectures which identifies link homologies with the Hilbert space of BPS states in the presence of branes, where the physical interpretation of gradings is in terms of charges of the branes ending on Lagrangian branes.

 Title: Laser Ranging to the Lost Lunokhod~1 Reflector Authors: Murphy, T. W., Jr; Adelberger, E. G.; Battat, J. B. R.; Hoyle, C. D.; Johnson, N. H.; McMillan, R. J.; Michelsen, E. L.; Stubbs, C. W.; Swanson, H. E. Publication: eprint arXiv:1009.5720 Publication Date: 09/2010 Origin: ARXIV Keywords: Astrophysics - Earth and Planetary Astrophysics Comment: 11 pages, 1 figure (color), submitted to Icarus Bibliographic Code: 2010arXiv1009.5720M

### Abstract

In 1970, the Soviet Lunokhod 1 rover delivered a French-built laser reflector to the Moon. Although a few range measurements were made within three months of its landing, these measurements---and any that may have followed---are unpublished and unavailable. The Lunokhod 1 reflector was, therefore, effectively lost until March of 2010 when images from the Lunar Reconnaissance Orbiter (LRO) provided a positive identification of the rover and determined its coordinates with uncertainties of about 100 m. This allowed the Apache Point Observatory Lunar Laser-ranging Operation (APOLLO) to quickly acquire a laser signal. The reflector appears to be in excellent condition, delivering a signal roughly four times stronger than its twin reflector on the Lunokhod 2 rover. The Lunokhod 1 reflector is especially valuable for science because it is closer to the Moon's limb than any of the other reflectors and, unlike the Lunokhod 2 reflector, we find that it is usable during the lunar day. We report the selenographic position of the reflector to few-centimeter accuracy, comment on the health of the reflector, and illustrate the value of this reflector for achieving science goals.

 Title: Microscopic Realization of the Kerr/CFT Correspondence Authors: Guica, Monica; Strominger, Andrew Publication: eprint arXiv:1009.5039 Publication Date: 09/2010 Origin: ARXIV Keywords: High Energy Physics - Theory, General Relativity and Quantum Cosmology Comment: 18 pages, no figures Bibliographic Code: 2010arXiv1009.5039G

### Abstract

Supersymmetric M/string compactifications to five dimensions contain BPS black string solutions with magnetic graviphoton charge P and near-horizon geometries which are quotients of AdS_3 x S^2. The holographic duals are typically known 2D CFTs with central charges c_L=c_R=6P^3 for large P. These same 5D compactifications also contain non-BPS but extreme Kerr-Newman black hole solutions with SU(2)_L spin J_L and electric graviphoton charge Q obeying Q^3 \leq J_L^2. It is shown that in the maximally charged limit Q^3 -> J_L^2, the near-horizon geometry coincides precisely with the right-moving temperature T_R=0 limit of the black string with magnetic charge P=J_L^{1/3}. The known dual of the latter is identified as the c_L=c_R=6J_L CFT predicted by the Kerr/CFT correspondence. Moreover, at linear order away from maximality, one finds a T_R \neq 0 quotient of the AdS_3 factor of the black string solution and the associated thermal CFT entropy reproduces the linearly sub-maximal Kerr-Newman entropy. Beyond linear order, for general Q^3<J_L^2, one has a finite-temperature quotient of a warped deformation of the magnetic string geometry. The corresponding dual deformation of the magnetic string CFT potentially supplies, for the general case, the c_L=c_R=6J_L CFT predicted by Kerr/CFT.

 Title: The Blue Tip of the Stellar Locus: Measuring Reddening with the SDSS Authors: Schlafly, Edward F.; Finkbeiner, Douglas P.; Schlegel, David J.; Jurić, Mario; Ivezić, \vZeljko; Gibson, Robert R.; Knapp, Gillian R.; Weaver, Benjamin A. Publication: eprint arXiv:1009.4933 Publication Date: 09/2010 Origin: ARXIV Keywords: Astrophysics - Galaxy Astrophysics, Astrophysics - Cosmology and Extragalactic Astrophysics Comment: 18 pages, 22 figures Bibliographic Code: 2010arXiv1009.4933S

### Abstract

We present measurements of reddening due to dust using the colors of stars in the Sloan Digital Sky Survey (SDSS). We measure the color of main sequence turn-off stars by finding the "blue tip" of the stellar locus: the prominent blue edge in the distribution of stellar colors. The method is sensitive to color changes of order 18, 12, 7, and 8 mmag of reddening in the colors u-g, g-r, r-i, and i-z, respectively, in regions measuring 90' by 14'. We present maps of the blue tip colors in each of these bands over the entire SDSS footprint, including the new dusty southern Galactic cap data provided by the SDSS-III. The results disfavor the best fit O'Donnell (1994) and Cardelli et al. (1989) reddening laws, but are well described by a Fitzpatrick (1999) reddening law with R_V = 3.1. The SFD dust map is found to trace the dust well, but overestimates reddening by factors of 1.4, 1.0, 1.2, and 1.4 in u-g, g-r, r-i, and i-z, largely due to the adopted reddening law. In select dusty regions of the sky, we find evidence for problems in the SFD temperature correction. A dust map normalization difference of 15% between the Galactic north and south sky may be due to these dust temperature errors.

 Title: Cavity Control of a Single-Electron Quantum Cyclotron:\\Measuring the Electron Magnetic Moment Authors: Hanneke, D.; Fogwell Hoogerheide, S.; Gabrielse, G. Publication: eprint arXiv:1009.4831 Publication Date: 09/2010 Origin: ARXIV Keywords: Physics - Atomic Physics, High Energy Physics - Experiment Bibliographic Code: 2010arXiv1009.4831H

### Abstract

Measurements with a one-electron quantum cyclotron determine the electron magnetic moment, given by $g/2 = 1.001\,159\,652\,180\,73\,(28)\,[0.28~\textrm{ppt}]$, and the fine structure constant, $\alpha^{-1}=137.035\,999\,084\,(51)\,[0.37~\textrm{ppb}]$. Brief announcements of these measurements are supplemented here with a more complete description of the one-electron quantum cyclotron and the new measurement methods, a discussion of the cavity control of the radiation field, a summary of the analysis of the measurements, and a fuller discussion of the uncertainties.

 Title: Asymptotic Symmetries and Charges in De Sitter Space Authors: Anninos, Dionysios; Ng, Gim Seng; Strominger, Andrew Publication: eprint arXiv:1009.4730 Publication Date: 09/2010 Origin: ARXIV Keywords: General Relativity and Quantum Cosmology, High Energy Physics - Theory Comment: 16 pages, 1 figure Bibliographic Code: 2010arXiv1009.4730A

### Abstract

The asymptotic symmetry group (ASG) at future null infinity (I^+) of four-dimensional de Sitter spacetimes is defined and shown to be given by the group of three-dimensional diffeomorphisms acting on I^+. Finite charges are constructed for each choice of ASG generator together with a two-surface on I^+. A conservation equation is derived relating the evolution of the charges with the radiation flux through I^+.

 Title: Single Color Centers Implanted in Diamond Nanostructures Authors: Hausmann, Birgit J. M.; Babinec, Thomas M.; Choy, Jennifer T.; Hodges, Jonathan S.; Hong, Sungkun; Bulu, Irfan; Yacoby, A.; Lukin, M. D.; Lončar, Marko Publication: eprint arXiv:1009.4224 Publication Date: 09/2010 Origin: ARXIV Keywords: Condensed Matter - Materials Science, Quantum Physics Comment: 20 pages, 7 figures Bibliographic Code: 2010arXiv1009.4224H

### Abstract

The development of materials processing techniques for optical diamond nanostructures containing a single color center is an important problem in quantum science and technology. In this work, we present the combination of ion implantation and top-down diamond nanofabrication in two scenarios: diamond nanopillars and diamond nanowires. The first device consists of a 'shallow' implant (~20nm) to generate Nitrogen-vacancy (NV) color centers near the top surface of the diamond crystal. Individual NV centers are then isolated mechanically by dry etching a regular array of nanopillars in the diamond surface. Photon anti-bunching measurements indicate that a high yield (>10%) of the devices contain a single NV center. The second device demonstrates 'deep' (~1\mu m) implantation of individual NV centers into pre-fabricated diamond nanowire. The high single photon flux of the nanowire geometry, combined with the low background fluorescence of the ultrapure diamond, allows us to sustain strong photon anti-bunching even at high pump powers.

 Title: Cold N+NH Collisions in a Magnetic Trap Authors: Hummon, Matthew T.; Tscherbul, Timur V.; Kłos, Jacek; Lu, Hsin-I; Tsikata, Edem; Campbell, Wesley C.; Dalgarno, Alexander; Doyle, John M. Publication: eprint arXiv:1009.2513 Publication Date: 09/2010 Origin: ARXIV Keywords: Physics - Atomic Physics, Physics - Chemical Physics Bibliographic Code: 2010arXiv1009.2513H

### Abstract

We present an experimental and theoretical study of atom-molecule collisions in a mixture of cold, trapped atomic nitrogen and NH molecules at a temperature of $\sim 600$~mK. We measure a small N+NH trap loss rate coefficient of $k^{(\mathrm{N+NH})}_\mathrm{loss} = 8(4) \times 10^{-13}$~cm$^{3}$s$^{-1}$. Accurate quantum scattering calculations based on {\it ab initio} interaction potentials are in agreement with experiment and indicate the magnetic dipole interaction to be the dominant loss mechanism. Our theory further indicates the ratio of N+NH elastic to inelastic collisions remains large ($>100$) into the mK regime.

 Title: Local Compressibility Measurements of Correlated States in Suspended Bilayer Graphene Authors: Martin, Jens; Feldman, Benjamin E.; Weitz, R. Thomas; Allen, Monica T.; Yacoby, Amir Publication: eprint arXiv:1009.2069 Publication Date: 09/2010 Origin: ARXIV Keywords: Condensed Matter - Mesoscale and Nanoscale Physics Comment: 9 pages, including 4 figures and supplementary materials Bibliographic Code: 2010arXiv1009.2069M

### Abstract

Bilayer graphene has attracted considerable interest due to the important role played by many-body effects, particularly at low energies. Here we report local compressibility measurements of a suspended graphene bilayer. We find that the energy gaps at filling factors v = 4 do not vanish at low fields, but instead merge into an incompressible region near the charge neutrality point at zero electric and magnetic field. These results indicate the existence of a zero-field ordered state and are consistent with the formation of either an anomalous quantum Hall state or a nematic phase with broken rotational symmetry. At higher fields, we measure the intrinsic energy gaps of broken-symmetry states at v = 0, 1 and 2, and find that they scale linearly with magnetic field, yet another manifestation of the strong Coulomb interactions in bilayer graphene.

 Title: Xogenesis Authors: Buckley, Matthew R.; Randall, Lisa Publication: eprint arXiv:1009.0270 Publication Date: 09/2010 Origin: ARXIV Keywords: High Energy Physics - Phenomenology Comment: 11 pages, 4 figures Bibliographic Code: 2010arXiv1009.0270B

### Abstract

We present a new paradigm for dark matter in which a dark matter asymmetry is established in the early universe that is then transferred to ordinary matter. We show this scenario can fit naturally into weak scale physics models, with a dark matter candidate mass of this order. We present several natural suppression mechanisms, including bleeding dark matter number density into lepton number, which occurs naturally in models with lepton-violating operators transferring the asymmetry.

 Title: SPT-CL J0546-5345: A Massive z>1 Galaxy Cluster Selected Via the Sunyaev-Zel'dovich Effect with the South Pole Telescope Authors: Brodwin, M.; Ruel, J.; Ade, P. A. R.;... Stubbs, C. W.; ; and 63 coauthors. Publication: The Astrophysical Journal, Volume 721, Issue 1, pp. 90-97 (2010). (ApJ Homepage) Publication Date: 09/2010 Origin: IOP ApJ Keywords: galaxies: clusters: individual: SPT-CL J0546-5345, galaxies: distances and redshifts, galaxies: evolution DOI: 10.1088/0004-637X/721/1/90 Bibliographic Code: 2010ApJ...721...90B

### Abstract

We report the spectroscopic confirmation of SPT-CL J0546-5345 at langzrang = 1.067. To date this is the most distant cluster to be spectroscopically confirmed from the 2008 South Pole Telescope (SPT) catalog, and indeed the first z>1 cluster discovered by the Sunyaev-Zel'dovich Effect (SZE). We identify 21 secure spectroscopic members within 0.9 Mpc of the SPT cluster position, 18 of which are quiescent, early-type galaxies. From these quiescent galaxies we obtain a velocity dispersion of 1179+232 –167 km s–1, ranking SPT-CL J0546-5345 as the most dynamically massive cluster yet discovered at z>1. Assuming that SPT-CL J0546-5345 is virialized, this implies a dynamical mass of M 200 = 1.0+0.6 –0.4 × 1015 M sun, in agreement with the X-ray and SZE mass measurements. Combining masses from several independent measures leads to a best-estimate mass of M 200 = (7.95 ± 0.92) × 1014 M sun. The spectroscopic confirmation of SPT-CL J0546-5345, discovered in the wide-angle, mass-selected SPT cluster survey, marks the onset of the high-redshift SZE-selected galaxy cluster era.

 Title: GALEX and Pan-STARRS1 Discovery of SN IIP 2010aq: The First Few Days After Shock Breakout in a Red Supergiant Star Authors: Gezari, S.; Rest, A.; Huber, M. E.; ... Stubbs, C. W.; ; and 33 coauthors. Publication: The Astrophysical Journal Letters, Volume 720, Issue 1, pp. L77-L81 (2010). (ApJL Homepage) Publication Date: 09/2010 Origin: IOP ApJ Keywords: supernovae: individual: SN 2010aq, surveys, ultraviolet: general DOI: 10.1088/2041-8205/720/1/L77 Bibliographic Code: 2010ApJ...720L..77G

### Abstract

We present the early UV and optical light curve of Type IIP supernova (SN) 2010aq at z = 0.0862, and compare it to analytical models for thermal emission following SN shock breakout in a red supergiant star. SN 2010aq was discovered in joint monitoring between the Galaxy Evolution Explorer (GALEX) Time Domain Survey (TDS) in the NUV and the Pan-STARRS1 Medium Deep Survey (PS1 MDS) in the g, r, i, and z bands. The GALEX and Pan-STARRS1 observations detect the SN less than 1 day after the shock breakout, measure a diluted blackbody temperature of 31, 000 ± 6000 K 1 day later, and follow the rise in the UV/optical light curve over the next 2 days caused by the expansion and cooling of the SN ejecta. The high signal-to-noise ratio of the simultaneous UV and optical photometry allows us to fit for a progenitor star radius of 700 ± 200R sun, the size of a red supergiant star. An excess in UV emission two weeks after shock breakout compared with SNe well fitted by model atmosphere-code synthetic spectra with solar metallicity is best explained by suppressed line blanketing due to a lower metallicity progenitor star in SN 2010aq. Continued monitoring of PS1 MDS fields by the GALEX TDS will increase the sample of early UV detections of Type II SNe by an order of magnitude and probe the diversity of SN progenitor star properties.

 Title: Precision Determination of Atmospheric Extinction at Optical and Near-infrared Wavelengths Authors: Burke, David L.; Axelrod, T.; Blondin, Stéphane; Claver, Chuck; Ivezić, Željko; Jones, Lynne; Saha, Abhijit; Smith, Allyn; Smith, R. Chris; Stubbs, Christopher W. Publication: The Astrophysical Journal, Volume 720, Issue 1, pp. 811-823 (2010). (ApJ Homepage) Publication Date: 09/2010 Origin: IOP ApJ Keywords: atmospheric effects, methods: observational, surveys, techniques: photometric DOI: 10.1088/0004-637X/720/1/811 Bibliographic Code: 2010ApJ...720..811B

### Abstract

The science goals for future ground-based all-sky surveys, such as the Dark Energy Survey, PanSTARRS, and the Large Synoptic Survey Telescope, require calibration of broadband photometry that is stable in time and uniform over the sky to precisions of 1% or better, and absolute calibration of color measurements that are similarly accurate. This performance will need to be achieved with measurements made from multiple images taken over the course of many years, and these surveys will observe in less than ideal conditions. This paper describes a technique to implement a new strategy to directly measure variations of atmospheric transmittance at optical wavelengths and application of these measurements to calibration of ground-based observations. This strategy makes use of measurements of the spectra of a small catalog of bright "probe" stars as they progress across the sky and back-light the atmosphere. The signatures of optical absorption by different atmospheric constituents are recognized in these spectra by their characteristic dependences on wavelength and airmass. State-of-the-art models of atmospheric radiation transport and modern codes are used to accurately compute atmospheric extinction over a wide range of observing conditions. We present results of an observing campaign that demonstrate that correction for extinction due to molecular constituents and aerosols can be done with precisions of a few millimagnitudes with this technique.

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