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Full-Text Articles in Physical Sciences and Mathematics

On The Progenitor Of Binary Neutron Star Merger Gw170817, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Dec 2017

On The Progenitor Of Binary Neutron Star Merger Gw170817, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

On 2017 August 17 the merger of two compact objects with masses consistent with two neutron stars was discovered through gravitational-wave (GW170817), gamma-ray (GRB 170817A), and optical (SSS17a/AT 2017gfo) observations. The optical source was associated with the early-type galaxy NGC 4993 at a distance of just ∼40 Mpc, consistent with the gravitational-wave measurement, and the merger was localized to be at a projected distance of ∼2 kpc away from the galaxy's center. We use this minimal set of facts and the mass posteriors of the two neutron stars to derive the first constraints on the progenitor of GW170817 ...


Nematic Topological Superconducting Phase In Nb-Doped Bi₂Se₃, Junying Shen, Wen-Yu He, Noah Fan Qi Yuan, Zengle Huang, Chang-Woo Cho, Seng Huat Lee, Yew San Hor, Kam Tuen Law, Rolf Lortz Dec 2017

Nematic Topological Superconducting Phase In Nb-Doped Bi₂Se₃, Junying Shen, Wen-Yu He, Noah Fan Qi Yuan, Zengle Huang, Chang-Woo Cho, Seng Huat Lee, Yew San Hor, Kam Tuen Law, Rolf Lortz

Physics Faculty Research & Creative Works

A nematic topological superconductor has an order parameter symmetry, which spontaneously breaks the crystalline symmetry in its superconducting state. This state can be observed, for example, by thermodynamic or upper critical field experiments in which a magnetic field is rotated with respect to the crystalline axes. The corresponding physical quantity then directly reflects the symmetry of the order parameter. We present a study on the superconducting upper critical field of the Nb-doped topological insulator NbxBi2Se3 for various magnetic field orientations parallel and perpendicular to the basal plane of the Bi2Se3 layers. The ...


First Low-Frequency Einstein@Home All-Sky Search For Continuous Gravitational Waves In Advanced Ligo Data, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Dec 2017

First Low-Frequency Einstein@Home All-Sky Search For Continuous Gravitational Waves In Advanced Ligo Data, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We report results of a deep all-sky search for periodic gravitational waves from isolated neutron stars in data from the first Advanced LIGO observing run. This search investigates the low frequency range of Advanced LIGO data, between 20 and 100 Hz, much of which was not explored in initial LIGO. The search was made possible by the computing power provided by the volunteers of the Einstein@Home project. We find no significant signal candidate and set the most stringent upper limits to date on the amplitude of gravitational wave signals from the target population, corresponding to a sensitivity depth of ...


Long-Range Interactions For Hydrogen: 6p-1s And 6p-2s Systems, Ulrich D. Jentschura, Chandra M. Adhikari Dec 2017

Long-Range Interactions For Hydrogen: 6p-1s And 6p-2s Systems, Ulrich D. Jentschura, Chandra M. Adhikari

Physics Faculty Research & Creative Works

The collisional shift of a transition constitutes an important systematic effect in highprecision spectroscopy. Accurate values for van der Waals interaction coefficients are required in order to evaluate the distance-dependent frequency shift. We here consider the interaction of excited hydrogen 6P atoms with metastable atoms (in the 2S state), in order to explore the influence of quasi-degenerate 2P and 6S states on the dipole-dipole interaction. The motivation for the calculation is given by planned high-precision measurements of the transition. Due to the presence of quasi-degenerate levels, one can use the non-retarded approximation for the interaction terms over wide distance ranges.


Estimating The Contribution Of Dynamical Ejecta In The Kilonova Associated With Gw170817, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Dec 2017

Estimating The Contribution Of Dynamical Ejecta In The Kilonova Associated With Gw170817, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

The source of the gravitational-wave (GW) signal GW170817, very likely a binary neutron star merger, was also observed electromagnetically, providing the first multi-messenger observations of this type. The two-week-long electromagnetic (EM) counterpart had a signature indicative of an r-process-induced optical transient known as a kilonova. This Letter examines how the mass of the dynamical ejecta can be estimated without a direct electromagnetic observation of the kilonova, using GW measurements and a phenomenological model calibrated to numerical simulations of mergers with dynamical ejecta. Specifically, we apply the model to the binary masses inferred from the GW measurements, and use the ...


The Stripe 82 Massive Galaxy Project. Iii. A Lack Of Growth Among Massive Galaxies, Kevin Bundy, Alexie Leauthaud, Shun Saito, Claudia Maraston, David A. Wake, Daniel Thomas Dec 2017

The Stripe 82 Massive Galaxy Project. Iii. A Lack Of Growth Among Massive Galaxies, Kevin Bundy, Alexie Leauthaud, Shun Saito, Claudia Maraston, David A. Wake, Daniel Thomas

Physics Faculty Research & Creative Works

The average stellar mass (M*) of high-mass galaxies (log M*/M > 11.5) is expected to grow by ∼30% since z ~ 1, largely through ongoing mergers that are also invoked to explain the observed increase in galaxy sizes. Direct evidence for the corresponding growth in stellar mass has been elusive, however, in part because the volumes sampled by previous redshift surveys have been too small to yield reliable statistics. In this work, we make use of the Stripe 82 Massive Galaxy Catalog (S82-MGC) to build a mass-limited sample of 41,770 galaxies log M*/M > 11.2) with optical-to-near-IR photometry ...


First Narrow-Band Search For Continuous Gravitational Waves From Known Pulsars In Advanced Detector Data, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Dec 2017

First Narrow-Band Search For Continuous Gravitational Waves From Known Pulsars In Advanced Detector Data, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signal-to-noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have been developed, allowing a fully coherent search for gravitational waves from known pulsars ...


Gw170608: Observation Of A 19 Solar-Mass Binary Black Hole Coalescence, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Dec 2017

Gw170608: Observation Of A 19 Solar-Mass Binary Black Hole Coalescence, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

On 2017 June 8 at 02:01:16.49 UTC, a gravitational-wave (GW) signal from the merger of two stellar-mass blackholes was observed by the two Advanced Laser Interferometer Gravitational-Wave Observatory detectors with a network signal-to-noise ratio of 13. This system is the lightest black hole binary so far observed, with component masses of 12+7 -2M⊙+2-2M⊙ (90% credible intervals). These lie in the range of measured black hole masses in low-mass X-ray binaries, thus allowing us to compare black holes detected through GWs with electromagnetic observations. The source's luminosity distance is 340+140 -140 ...


Neutrino Pair Cerenkov Radiation For Tachyonic Neutrinos, Ulrich D. Jentschura, Istvan Nandori Nov 2017

Neutrino Pair Cerenkov Radiation For Tachyonic Neutrinos, Ulrich D. Jentschura, Istvan Nandori

Physics Faculty Research & Creative Works

The emission of a charged light lepton pair by a superluminal neutrino has been identified as a major factor in the energy loss of highly energetic neutrinos. The observation of PeV neutrinos by IceCube implies their stability against lepton pair Cerenkov radiation. Under the assumption of a Lorentz-violating dispersion relation for highly energetic superluminal neutrinos, one may thus constrain the Lorentz-violating parameters. A kinematically different situation arises when one assumes a Lorentz-covariant, space-like dispersion relation for hypothetical tachyonic neutrinos, as an alternative to Lorentz-violating theories. We here discuss a hitherto neglected decay process, where a highly energetic tachyonic neutrino may ...


Search For High-Energy Neutrinos From Binary Neutron Star Merger Gw170817 With Antares, Icecube, And The Pierre Auger Observatory, A. Albert, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Nov 2017

Search For High-Energy Neutrinos From Binary Neutron Star Merger Gw170817 With Antares, Icecube, And The Pierre Auger Observatory, A. Albert, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

The Advanced LIGO and Advanced Virgo observatories recently discovered gravitational waves from a binary neutron star inspiral. A short gamma-ray burst (GRB) that followed the merger of this binary was also recorded by the Fermi Gamma-ray Burst Monitor (Fermi-GBM), and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory (INTEGRAL), indicating particle acceleration by the source. The precise location of the event was determined by optical detections of emission following the merger. We searched for high-energy neutrinos from the merger in the GeV-EeV energy range using the Antares, IceCube, and Pierre Auger Observatories. No neutrinos directionally ...


Enhanced Optical Coupling And Raman Scattering Via Microscopic Interface Engineering, Jonathan V. Thompson, Brett H. Hokr, Wihan Kim, Charles W. Ballmann, Brian E. Applegate, Javier Jo, Alexey Yamilov, Hui Cao, Marlan O. Scully, Vladislav V. Yakovlev Nov 2017

Enhanced Optical Coupling And Raman Scattering Via Microscopic Interface Engineering, Jonathan V. Thompson, Brett H. Hokr, Wihan Kim, Charles W. Ballmann, Brian E. Applegate, Javier Jo, Alexey Yamilov, Hui Cao, Marlan O. Scully, Vladislav V. Yakovlev

Physics Faculty Research & Creative Works

Spontaneous Raman scattering is an extremely powerful tool for the remote detection and identification of various chemical materials. However, when those materials are contained within strongly scattering or turbid media, as is the case in many biological and security related systems, the sensitivity and range of Raman signal generation and detection is severely limited. Here, we demonstrate that through microscopic engineering of the optical interface, the optical coupling of light into a turbid material can be substantially enhanced. This improved coupling facilitates the enhancement of the Raman scattering signal generated by molecules within the medium. In particular, we detect at ...


Gw170814: A Three-Detector Observation Of Gravitational Waves From A Binary Black Hole Coalescence, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Oct 2017

Gw170814: A Three-Detector Observation Of Gravitational Waves From A Binary Black Hole Coalescence, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

On August 14, 2017 at 10 30:43 UTC, the Advanced Virgo detector and the two Advanced LIGO detectors coherently observed a transient gravitational-wave signal produced by the coalescence of two stellar mass black holes, with a false-alarm rate of ≲1 in 27 000 years. The signal was observed with a three-detector network matched-filter signal-to-noise ratio of 18. The inferred masses of the initial black holes are 30.5-3.0+5.7M⊙ and 25.3-4.2+2.8M⊙ (at the 90% credible level). The luminosity distance of the source is 540-210+130 Mpc, corresponding to ...


Multi-Messenger Observations Of A Binary Neutron Star Merger, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Oct 2017

Multi-Messenger Observations Of A Binary Neutron Star Merger, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+ 8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to ...


Gw170817: Observation Of Gravitational Waves From A Binary Neutron Star Inspiral, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Oct 2017

Gw170817: Observation Of Gravitational Waves From A Binary Neutron Star Inspiral, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

On August 17, 2017 at 12-41:04 UTC the Advanced LIGO and Advanced Virgo gravitational-wave detectors made their first observation of a binary neutron star inspiral. The signal, GW170817, was detected with a combined signal-to-noise ratio of 32.4 and a false-alarm-rate estimate of less than one per 8.0 x 104 years. We infer the component masses of the binary to be between 0.86 and 2.26 M, in agreement with masses of known neutron stars. Restricting the component spins to the range inferred in binary neutron stars, we find the component masses to be in the ...


Upper Limits On Gravitational Waves From Scorpius X-1 From A Model-Based Cross-Correlation Search In Advanced Ligo Data, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Sep 2017

Upper Limits On Gravitational Waves From Scorpius X-1 From A Model-Based Cross-Correlation Search In Advanced Ligo Data, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We present the results of a semicoherent search for continuous gravitational waves from the low-mass X-ray binary Scorpius X-1, using data from the first Advanced LIGO observing run. The search method uses details of the modeled, parametrized continuous signal to combine coherently data separated by less than a specified coherence time, which can be adjusted to trade off sensitivity against computational cost. A search was conducted over the frequency range 25-2000 Hz, spanning the current observationally constrained range of binary orbital parameters. No significant detection candidates were found, and frequency-dependent upper limits were set using a combination of sensitivity estimates ...


Robust Odd-Parity Superconductivity In The Doped Topological Insulator NbₓBi₂Se₃, M. P. Smylie, K. Willa, H. Claus, A. Snezhko, I. Martin, W.-K. Kwok, Y. Qiu, Yew San Hor, E. Bokari, P. Niraula, A. Kayani, V. Mishra, U. Welp Sep 2017

Robust Odd-Parity Superconductivity In The Doped Topological Insulator NbₓBi₂Se₃, M. P. Smylie, K. Willa, H. Claus, A. Snezhko, I. Martin, W.-K. Kwok, Y. Qiu, Yew San Hor, E. Bokari, P. Niraula, A. Kayani, V. Mishra, U. Welp

Physics Faculty Research & Creative Works

We present resistivity and magnetization measurements on proton-irradiated crystals demonstrating that the superconducting state in the doped topological insulator NbxBi2Se3 (x=0.25) is surprisingly robust against disorder-induced electron scattering. The superconducting transition temperature TC decreases without indication of saturation with increasing defect concentration, and the corresponding scattering rates far surpass expectations based on conventional theory. The low-temperature variation of the London penetration depth Δλ(T) follows a power law [Δλ(T)T2] indicating the presence of symmetry-protected point nodes. Our results are consistent with the proposed robust nematic Eu pairing state ...


Long-Range Interactions Of Hydrogen Atoms In Excited States. Iii. Ns−1s Interactions For N ≥ 3, Chandra M. Adhikari, V. Debierre, Ulrich D. Jentschura Sep 2017

Long-Range Interactions Of Hydrogen Atoms In Excited States. Iii. Ns−1s Interactions For N ≥ 3, Chandra M. Adhikari, V. Debierre, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

The long-range interaction of excited neutral atoms has a number of interesting and surprising properties such as the prevalence of long-range oscillatory tails and the emergence of numerically large van der Waals C6 coefficients. Furthermore, the energetically quasidegenerate nP states require special attention and lead to mathematical subtleties. Here we analyze the interaction of excited hydrogen atoms in nS states (3 ≤ n ≤ 12) with ground-state hydrogen atoms and find that the C6 coefficients roughly grow with the fourth power of the principal quantum number and can reach values in excess of 240000 (in atomic units) for states with n ...


Recent Advances In Understanding The Structure And Properties Of Amorphous Oxide Semiconductors, Julia E. Medvedeva, D. B. Buchholz, Robert P. H. Chang Sep 2017

Recent Advances In Understanding The Structure And Properties Of Amorphous Oxide Semiconductors, Julia E. Medvedeva, D. B. Buchholz, Robert P. H. Chang

Physics Faculty Research & Creative Works

Amorphous oxide semiconductors (AOSs)--ternary or quaternary oxides of post-transition metals such as In-Sn-O, Zn-Sn-O, or In-Ga-Zn-O–have been known for a decade and have attracted a great deal of attention as they possess several technological advantages, including low-temperature large-area deposition, mechanical flexibility, smooth surfaces, and high carrier mobility that is an order of magnitude larger than that of amorphous silicon (a-Si:H). Compared to their crystalline counterparts, the structure of AOSs is extremely sensitive to deposition conditions, stoichiometry, and composition, giving rise to a wide range of tunable optical and electrical properties. The large parameter space and the resulting ...


All-Sky Search For Periodic Gravitational Waves In The O1 Ligo Data, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Sep 2017

All-Sky Search For Periodic Gravitational Waves In The O1 Ligo Data, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We report on an all-sky search for periodic gravitational waves in the frequency band 20-475 Hz and with a frequency time derivative in the range of [-1.0,+0.1] x 10-8 Hz/s. Such a signal could be produced by a nearby spinning and slightly nonaxisymmetric isolated neutron star in our galaxy. This search uses the data from Advanced LIGO's first observational run, O1. No periodic gravitational wave signals were observed, and upper limits were placed on their strengths. The lowest upper limits on worst-case (linearly polarized) strain amplitude h0 are ∼4 x 10-25 near ...


Electron-Impact Ionization Of Laser-Aligned Atoms -- Contributions From Both Natural And Unnatural-Parity States, Andrew James Murray, James Colgan, Don H. Madison, Matthew Harvey, Ahmad Sakaamini Aug 2017

Electron-Impact Ionization Of Laser-Aligned Atoms -- Contributions From Both Natural And Unnatural-Parity States, Andrew James Murray, James Colgan, Don H. Madison, Matthew Harvey, Ahmad Sakaamini

Physics Faculty Research & Creative Works

Synopsis. The progress of experimental and theoretical measurements for (e,2e) ionization cross sections from laser-aligned atoms is presented here. It is found that both natural and unnatural parity contributions must be included in the models to emulate the experimental data.


(E,2e) Ionization Studies Of N₂ At Low To Intermediate Energies From A Coplanar Geometry To The Perpendicular Plane, Ahmad Sakaamini, Matthew Harvey, Sadek Amami, Andrew James Murray, Don H. Madison, Chuangang Ning Aug 2017

(E,2e) Ionization Studies Of N₂ At Low To Intermediate Energies From A Coplanar Geometry To The Perpendicular Plane, Ahmad Sakaamini, Matthew Harvey, Sadek Amami, Andrew James Murray, Don H. Madison, Chuangang Ning

Physics Faculty Research & Creative Works

Synopsis. The progress of experimental and theoretical measurements for (e,2e) ionization cross sections from Nitrogen molecules is presented. Results are given for energies from ~10 eV above the ionization potential (IP) through to ~100 eV above the IP for the 3σg, 1πu and 2σg states.


Inverse Design Of Perfectly Transmitting Eigenchannels In Scattering Media, Milan Koirala, Raktim Sarma, Hui Cao, Alexey Yamilov Aug 2017

Inverse Design Of Perfectly Transmitting Eigenchannels In Scattering Media, Milan Koirala, Raktim Sarma, Hui Cao, Alexey Yamilov

Physics Faculty Research & Creative Works

Light-matter interactions inside a turbid medium can be controlled by tailoring the spatial distribution of energy density throughout the system. Wavefront shaping allows selective coupling of incident light to different transmission eigenchannels, producing dramatically different spatial intensity profiles. In contrast to the density of transmission eigenvalues that is dictated by the universal bimodal distribution, the spatial structures of the eigenchannels are not universal and depend on the confinement geometry of the system. Here, we develop and verify a model for the transmission eigenchannel with the corresponding eigenvalue close to unity. By projecting the original problem of two-dimensional diffusion in a ...


Theory Of Retrieving Orientation-Resolved Molecular Information Using Time-Domain Rotational Coherence Spectroscopy, Xu Wang, Anh-Thu Le, Zhaoyan Zhou, Hui Wei, C. D. Lin Aug 2017

Theory Of Retrieving Orientation-Resolved Molecular Information Using Time-Domain Rotational Coherence Spectroscopy, Xu Wang, Anh-Thu Le, Zhaoyan Zhou, Hui Wei, C. D. Lin

Physics Faculty Research & Creative Works

We provide a unified theoretical framework for recently emerging experiments that retrieve fixed-in-space molecular information through time-domain rotational coherence spectroscopy. Unlike a previous approach by Makhija et al. (V. Makhija, arXiv:1611.06476), our method can be applied to the retrieval of both real-valued (e.g., ionization yield) and complex-valued (e.g., induced dipole moment) molecular response information. It is also a direct retrieval method without using iterations. We also demonstrate that experimental parameters, such as the fluence of the aligning laser pulse and the rotational temperature of the molecular ensemble, can be quite accurately determined using a statistical method.


Natural & Unnatural-Parity Contributions In Electron-Impact Ionization Of Laser-Aligned Atoms, Andrew James Murray, James Colgan, Don H. Madison, Matthew Harvey, Ahmad Sakaamini, James Pursehouse, Kate Nixon, Al Stauffer Aug 2017

Natural & Unnatural-Parity Contributions In Electron-Impact Ionization Of Laser-Aligned Atoms, Andrew James Murray, James Colgan, Don H. Madison, Matthew Harvey, Ahmad Sakaamini, James Pursehouse, Kate Nixon, Al Stauffer

Physics Faculty Research & Creative Works

Differential cross section measurements from laser-aligned Mg atoms are compared to theoretical calculations using both time dependent and time-independent formalisms. It is found that both natural and unnatural parity contributions to the calculated cross sections are required to emulate the data when the state is aligned out of the scattering plane.


Determination Of The Energy Band Gap Of Bi₂Se₃, G. Martinez, B. A. Piot, M. Hakl, M. Potemski, Yew San Hor Jul 2017

Determination Of The Energy Band Gap Of Bi₂Se₃, G. Martinez, B. A. Piot, M. Hakl, M. Potemski, Yew San Hor

Physics Faculty Research & Creative Works

Despite intensive investigations of Bi2Se3 in past few years, the size and nature of the bulk energy band gap of this well-known 3D topological insulator still remain unclear. Here we report on a combined magneto-transport, photoluminescence and infrared transmission study of Bi2Se3, which unambiguously shows that the energy band gap of this material is direct and reaches Eg = (220 ± 5) meV at low temperatures.


Enhanced Coupling Of Light Into A Turbid Medium Through Microscopic Interface Engineering, Jonathan V. Thompson, Brett H. Hokr, Wihan Kim, Charles W. Ballmann, Brian E. Applegate, Javier Jo, Alexey Yamilov, Hui Cao, Marlan O. Scully, Vladislav V. Yakovlev Jul 2017

Enhanced Coupling Of Light Into A Turbid Medium Through Microscopic Interface Engineering, Jonathan V. Thompson, Brett H. Hokr, Wihan Kim, Charles W. Ballmann, Brian E. Applegate, Javier Jo, Alexey Yamilov, Hui Cao, Marlan O. Scully, Vladislav V. Yakovlev

Physics Faculty Research & Creative Works

There are many optical detection and sensing methods used today that provide powerful ways to diagnose, characterize, and study materials. For example, the measurement of spontaneous Raman scattering allows for remote detection and identification of chemicals. Many other optical techniques provide unique solutions to learn about biological, chemical, and even structural systems. However, when these systems exist in a highly scattering or turbid medium, the optical scattering effects reduce the effectiveness of these methods. In this article, we demonstrate a method to engineer the geometry of the optical interface of a turbid medium, thereby drastically enhancing the coupling efficiency of ...


Superfluid-Mott Glass Quantum Multicritical Point On A Percolating Lattice, Martin Puschmann, Thomas Vojta Jul 2017

Superfluid-Mott Glass Quantum Multicritical Point On A Percolating Lattice, Martin Puschmann, Thomas Vojta

Physics Faculty Research & Creative Works

We employ large-scale Monte Carlo simulations to study a particle-hole symmetric site-diluted quantum rotor model in two dimensions. The ground state phase diagram of this system features two distinct quantum phase transitions between the superuid and the insulating (Mott glass) phases. They are separated by a multicritical point. The generic transition for dilutions below the lattice percolation threshold is driven by quantum uctuations while thetransition across the percolation threshold is due to the geometric uctuations of the lattice. We determine the location of the multicritical point between these two transitions and find its critical behavior. The multicritical exponents read z ...


Search For High-Energy Neutrinos From Gravitational Wave Event Gw151226 And Candidate Lvt151012 With Antares And Icecube, A. Albert, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Jul 2017

Search For High-Energy Neutrinos From Gravitational Wave Event Gw151226 And Candidate Lvt151012 With Antares And Icecube, A. Albert, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

The Advanced LIGO observatories detected gravitational waves from two binary black hole mergers during their first observation run (O1). We present a high-energy neutrino follow-up search for the second gravitational wave event, GW151226, as well as for gravitational wave candidate LVT151012. We find two and four neutrino candidates detected by IceCube, and one and zero detected by Antares, within ±500 s around the respective gravitational wave signals, consistent with the expected background rate. None of these neutrino candidates are found to be directionally coincident with GW151226 or LVT151012. We use nondetection to constrain isotropic-equivalent high-energy neutrino emission from GW151226, adopting ...


Search For Intermediate Mass Black Hole Binaries In The First Observing Run Of Advanced Ligo, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Jul 2017

Search For Intermediate Mass Black Hole Binaries In The First Observing Run Of Advanced Ligo, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

During their first observational run, the two Advanced LIGO detectors attained an unprecedented sensitivity, resulting in the first direct detections of gravitational-wave signals produced by stellar-mass binary black hole systems. This paper reports on an all-sky search for gravitational waves (GWs) from merging intermediate mass black hole binaries (IMBHBs). The combined results from two independent search techniques were used in this study: the first employs a matched-filter algorithm that uses a bank of filters covering the GW signal parameter space, while the second is a generic search for GW transients (bursts). No GWs from IMBHBs were detected; therefore, we constrain ...


Quantum Percolation Phase Transition And Magnetoelectric Dipole Glass In Hexagonal Ferrites, S. E. Rowley, Thomas Vojta, A. T. Jones, W. Guo, J. Oliveira, For Full List Of Authors, See Publisher's Website. Jul 2017

Quantum Percolation Phase Transition And Magnetoelectric Dipole Glass In Hexagonal Ferrites, S. E. Rowley, Thomas Vojta, A. T. Jones, W. Guo, J. Oliveira, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

Hexagonal ferrites not only have enormous commercial impact (£2 billion/year in sales) due to applications that include ultrahigh-density memories, credit-card stripes, magnetic bar codes, small motors, and low-loss microwave devices, they also have fascinating magnetic and ferroelectric quantum properties at low temperatures. Here we report the results of tuning the magnetic ordering temperature in PbFe12-xGaxO19 to zero by chemical substitution x. The phase transition boundary is found to vary as TN ∼ (1-x/xc)2/3 with xc very close to the calculated spin percolation threshold, which we determine by Monte Carlo ...