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Physics

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Displaying 926 - 950 of 2466

Cooperative Dynamics in a Model DPPC Membrane Arise from Membrane Layer Interactions

December 19, 2018
Author(s)
Kiley Kennedy, Neha Shafique, Jack F. Douglas, Francis W. Starr
The dynamics of model membranes can be highly heterogeneous, especially in more ordered dense phases. Experimentally, monolayers are often studied as a model system to infer the properties of membranes. To better understand the origins of this

Combined error signal in Ramsey spectroscopy of clock transitions

December 18, 2018
Author(s)
V. I. Yudin, A. V. Taichenachev, M. Y. Basalaev, T. Zanon-Willette, Juniper Wren Y. Pollock, Moshe Shuker, Elizabeth Donley, John Kitching
We have developed a universal method to form the reference signal for the stabilization of arbitrary atomic clocks based on Ramsey spectroscopy that uses an interrogation scheme of the atomic system with two different Ramsey periods and a specially

Quantum optimal control of the dissipative production of a maximally entangled state

December 14, 2018
Author(s)
Karl P. Horn, Florentin Reiter, Yiheng Lin, Dietrich Leibfried, Christiane P. Koch
Entanglement generation can be robust against noise in approaches that deliberately incorporate dissipation into the system dynamics. The presence of additional dissipation channels may, however, limit fidelity and speed of the process. Here we show how

Diagonal Slice Four-Wave Mixing: Natural Separation of Coherent Broadening Mechanisms

December 13, 2018
Author(s)
Travis M. Autry, Geoffrey M. Diederich, Mark E. Siemens
We present an ultrafast coherent spectroscopy data acquisition scheme that samples slices of the time domain used in multidimensional coherent spectroscopy to achieve faster data collection than full spectra. We derive analytical expressions for resonance

Atomic clock performance beyond Earths gravitational limit

December 6, 2018
Author(s)
William F. McGrew, Xiaogang Zhang, Robert J. Fasano, Stefan A. Schaeffer, Kyle P. Beloy, Daniele Nicolodi, Roger C. Brown, N. Hinkley, G. Milani, Marco Schioppo, T. H. Yoon, Andrew D. Ludlow
The passage of time is tracked by counting oscillations of a suitable frequency reference (e.g., the number of revolutions of Earth around the sun or the number of swings of a pendulum of a grandfather clock). By referencing the oscillations arising from

Approximating vibronic spectroscopy with imperfect quantum optics

November 23, 2018
Author(s)
W.R. Clements, Jelmer Renema, Andreas Eckstein, Antonio A. Valido, Adriana Lita, Thomas Gerrits, Sae Woo Nam, Steven Kolthammer, Joonsuk Huh
We study the impact of experimental imperfections on a recently proposed protocol for performing quantum simulations of vibronic spectroscopy. Specifically, we propose a method for quantifying the impact of these imperfections, optimizing an experiment to

Recommended electron-impact excitation and ionization cross sections for Be I

November 23, 2018
Author(s)
FNU Dipti, Tapasi Das, klaus Bartschat, I Bray, D Fursa, O Zatsarinny, C Ballance, H-K Chung, Yuri Ralchenko
Analytic fits to the recommended electron-impact excitation and ionization cross sections for Be I are presented. The lowest 19 terms of configurations 2snl (n 4) and 2p2 terms below the first ionization limit are considered. The fits are based on the

Quantum Process Fidelity Bounds from Sets of Input States

November 21, 2018
Author(s)
Emanuel H. Knill, Karl H. Mayer
We investigate the problem of bounding the quantum process fidelity given bounds on the fidelities between target states and the action of a process on a set of pure input states. We formulate the problem as a semidefinite program and prove convexity of

AC stark shifts of dark resonances probed with Ramsey spectroscopy

November 16, 2018
Author(s)
James Wesley Y. Pollock, V. I. Yudin, Moshe Shuker, M. Y. Basalaev, A. V. Taichenachev, Xiaochi Liu, John E. Kitching, Elizabeth A. Donley
The off-resonant AC Stark shift for coherent population trapping (CPT) resonances probed with Ramsey spectroscopy is investigated experimentally and theoretically. Measurements with laser- cooled 87Rb atoms show excellent quantitative agreement with a

Hierarchically Patterned Elastomeric and Thermoplastic Polymer Films through Nanoimprinting and Ultraviolet Light Exposure

November 13, 2018
Author(s)
Jack F. Douglas, Ying Chen, Manish Kulkarni, Allan Marshall, Alamgir Karim, ZiLu Wang, Xiaoteng Wang, Abdullah Al-Enizi, Ahmed Elzatahry, Andrey V. Dobrynin
We develop a simple and generally applicable method to fabricate hierarchical interfacial patterns in elastomer and thermoplastic polymer films through a combination of nanoimprinting and UVO microlithography. Using this method, tunable and hierarchically

Optimizing linearity in high-speed photodiodes

November 7, 2018
Author(s)
Josue Davila-Rodriguez, X. Xie, J. Zang, Christian J. Long, Tara M. Fortier, Holly F. Leopardi, Takuma Nakamura, J. C. Campbell, Scott A. Diddams, Franklyn J. Quinlan
Analog photonic links require high fidelity, high speed optical-to-electrical conversion for applications such as radio-over-fiber, synchronization at kilometer-scale facilities, and low- noise electronic signal generation. Nonlinearity is a particularly

Tuning the Relaxation of Nanopatterned Polymer Films with Polymer-Grafted Nanoparticles: Observation of EntropyEnthalpy Compensation

November 6, 2018
Author(s)
Jack F. Douglas, Xiaoteng Wang, Sonal Bhadauriya, Ren Zhang, Praveen Pitliya, Dharmaraj Raghavan, Alamgir Karim
We show that the previously observed polymeric clustering of nanoparticles (NPs) with grafted chains within polymer matrices can be pattern-directed by nanoimprinting ultrathin nanocomposite films so that the NPs segregate to thicker film regions where

Measuring the difference in nuclear charge radius of Xe isotopes by EUV spectroscopy of highly charged Na-like ions

November 5, 2018
Author(s)
Roshani Silwal, A. Lapierre, John D. Gillaspy, Joan M. Dreiling, S A. Blundell, Dipti Goyal, A. Borovik, Jr., G Gwinner, A.C.C. Villari, Yuri Ralchenko, Endre Takacs
The difference in the mean-square nuclear charge radius of xenon isotopes was measured utilizing a method based on extreme ultraviolet spectroscopy of highly charged Na-like ions. The isotope shift of the Na-like D1 (3s 2S1/2 − 3p 2P1/2) transition between

Modulated Photocurrent Measurements in Double Junction Solar Cells

November 4, 2018
Author(s)
Nicolas Marquez Peraca, Behrang Hamadani
Frequency dependent external quantum efficiency (EQE) measurements were performed on double junction solar cells by a custom-designed system consisting of an array of various monochromatic LEDs. Some LEDs were pulsed as a function of frequency while others

Periodic Table of the Elements

November 3, 2018
Author(s)
Karen Olsen
The periodic table contains NIST's latest critically evaluated data for atomic properties of the elements.

Certifying Quantum Randomness by Probability Estimation

October 31, 2018
Author(s)
Emanuel H. Knill, Yanbao Zhang, Peter L. Bierhorst
We introduce probability estimation, a broadly applicable frameworkto certify randomness in a finite sequence of measurements subject to verifiable physical constraints and with respect to classical side information. Examples include randomness from single

Reversible Kerr-soliton generation

October 16, 2018
Author(s)
Daniel C. Cole, Jordan R. Stone, Scott B. Papp
We demonstrate deterministic and reversible generation of single Kerr-microresonator solitons using a phase-modulated pump laser. In agreement with simulations, modulation enables soliton generation from a below-threshold background and provides control of

Monte Carlo Simulation of Cylinders with Short-Range Attractions

September 12, 2018
Author(s)
Harold W. Hatch, Nathan Mahynski, R. P. Murphy, Marco Blanco, Vincent K. Shen
Cylindrical or rod-like particles are promising materials for the applications of fillers in nanocomposite ma- terials and additives to control rheological properties of colloidal suspensions. Recent advances in particle synthesis allows for cylinders to

Lifetime of the metastable 2 P 1/2 state of F-like Ar 9+ isolated in a compact Penning trap

September 6, 2018
Author(s)
Samuel M. Brewer, Joan M. Dreiling, Nicholas D. Guise, Shannon M. Hoogerheide, Aung Naing, Joseph N. Tan
Multiple-ionized atoms can be captured at low energy in a compact Penning trap, allowing the isolation of a single charge state to measure the radiative lifetime of an atomic state that decays via weakly allowed transitions. Such a measurement is reported

Transition probabilities of Co II, weak lines to the ground and low metastable levels

September 5, 2018
Author(s)
James E. Lawler, T. Feigenson, Chris Sneden, John J. Cowan, Gillian Nave
New branching fraction measurements based primarily on data from a cross dispersed echelle spectrometer are reported for 84 lines of Co II. The branching fractions for 82 lines are converted to absolute atomic transition probabilities using radiative
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