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From Paper: Coherent control of the noninstantaneous nonlinear power-law response in resonant nanostructures

Published: Jan 2020

From Paper: Coherent control of the noninstantaneous nonlinear power-law response in resonant nanostructures

Published: Jan 2020

- #HarmonicGenerations #nanostructures #SHG #StrongIllumination #law

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From Paper: Adiabatic four-wave mixing frequency conversion

Published: Sep 2018

From Paper: Adiabatic four-wave mixing frequency conversion

Published: Sep 2018

- By using a method from atomic physics to adiabatically excite a two level system, we predict and later show aseveral methods to achieve such desing in a multiple mediums including silicon photonics which enables full 100 % efficinecy of nonlinear frequency conversion by wave mixing frequnecy conversion

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Authors: Emiko Hiyama, Masayasu Kamimura

Published: Sep 2018

Authors: Emiko Hiyama, Masayasu Kamimura

Published: Sep 2018

We review our calculation method, Gaussian expansion method (GEM), and itsapplications to various few-body (3- to 5-body) systems such as 1) few-nucleonsystems, 2) few-body structure of hypernuclei, 3) clustering structure of lightnuclei and unstable nuclei, 4) exotic atoms/molecules, 5) cold atoms, 6)nuclear astrophysics and 7) structure of exotic hadrons. Showing examples inour published papers, we explain i) high accuracy of GEM calculations and itsreason, ii) wide applicability of GEM and iii) successful predictions by GEMcalculations before measurements. GEM was proposed 30 years ago and has beenapplied to a variety of subjects. To solve few-body Schroedinger equationsaccurately, use is made of the Rayleigh-Ritz variational method for boundstates, the complex-scaling method for resonant states and the Kohn-typevariational principle to S-matrix for scattering states. The total wavefunction is expanded in terms of few-body Gaussian basis functions spanned overall the sets of rearrangement Jacobi coordinates. Gaussians with ranges ingeometric progression work very well both for short-range and long-rangebehavior of the few-body wave functions. Use of Gaussians with complex rangesgives much more accurate solution when the wave function has many oscillations.

Retrieved from arxiv

Retrieved from arxiv

Authors: Ajoy, A., et al

Published: Aug 2018

Authors: Ajoy, A., et al

Published: Aug 2018

We describe the construction of a fast field cycling device capable ofsweeping a 4-order-of-magnitude range of magnetic fields, from ~1mT to 7T, inunder 700ms. Central to this system is a high-speed sample shuttling mechanismbetween a superconducting magnet and a magnetic shield, with the capability toaccess arbitrary fields in between with high resolution. Our instrument servesas a versatile platform to harness the inherent dichotomy of spin dynamics onoffer at low and high fields - in particular, the low anisotropy, fast spinmanipulation, and rapid entanglement growth at low field as well as the longspin lifetimes, spin specific control, and efficient inductive measurementpossible at high fields. Exploiting these complementary capabilities in asingle device open up applications in a host of problems in quantum control,sensing, and information storage, besides in nuclear hypepolarization,relaxometry and imaging. In particular, in this paper, we focus on the abilityof the device to enable low-field hyperpolarization of 13C nuclei in diamondvia optically pumped electronic spins associated with Nitrogen Vacancy (NV)defect centers.

Retrieved from arxiv

Retrieved from arxiv

Authors: Sajad Taghipour, Mohsen Vafaee

Published: Aug 2018

Authors: Sajad Taghipour, Mohsen Vafaee

Published: Aug 2018

We numerically solved the full-dimensional electronic time-dependentSchr\"{o}dinger equation for H$_2^+$ with Born-Oppenheimer approximation underdifferent sin$^2$-shaped and trapezoidal laser pulses at some differentwavelengths, with $I=$1 $\times 10^{13}$ Wcm$^{-2}$, 3 $\times 10^{13}$Wcm$^{-2}$, and 6 $\times 10^{13}$ Wcm$^{-2}$ intensity at 4.73 a.u. and 7.0a.u. internuclear distances. Some structures such as complexity, minima, andoscillatory patterns appeared in the high-order harmonic generation (HHG)spectra are investigated in this work by considering the electron localization,electron nonadiabatic dynamics, spatially asymmetric of the HHG, and the Rabifrequency of the population of the ground and excited electronic states tobetter understand the origins of these structures in the HHG spectrum. We willclear that the origin of complicated patterns of the HHG spectra insin$^2$-shaped laser pulse is due to that the most portion of the HHG emissionoccurs at the falling part of the laser pulse. We explore that the oscillatorypattern in the HHG spectra originate from an oscillatory pattern in the $S_g$and $S_u$ spectra and these oscillatory patterns in turn are due to thenonadiabatic electronic behavior appeared as the slow oscillation pattern inthe ground and first excited electronic states populations. Also, our resultshows that the minima of the HHG are related to the oscillatory patterns in$S_g$ and $S_u$ spectra.

Retrieved from arxiv

Retrieved from arxiv

Authors: Prateek Puri, Michael Mills, Elizabeth P. West, Christian Schneider, Eric. R. Hudson

Published: Aug 2018

Authors: Prateek Puri, Michael Mills, Elizabeth P. West, Christian Schneider, Eric. R. Hudson

Published: Aug 2018

We demonstrate an ion shuttling technique for high-resolution control ofatom-ion collision energy by translating an ion held within a radio-frequencytrap through a magneto-optical atom trap. The technique is demonstrated bothexperimentally and through numerical simulations, with the experimental resultsindicating control of ion kinetic energies from $0.05-1$ K with a fractionalresolution of $\sim10$ and the simulations demonstrating that kinetic energycontrol up to $120$ K with a maximum predicted resolution of $\sim100$ ispossible, offering order-of-magnitude improvements over most alternativetechniques. Lastly, we perform a proof-of-principle chemistry experiment usingthis technique and outline how the method may be refined in the future andapplied to the study of molecular ion chemistry.

Retrieved from arxiv

Retrieved from arxiv

Authors: Alec Owens, Sergei N. Yurchenko, Vladimir Špirko

Published: Aug 2018

Authors: Alec Owens, Sergei N. Yurchenko, Vladimir Špirko

Published: Aug 2018

A robust variational approach is used to investigate the sensitivity of therotation-vibration spectrum of phosphine (PH$_3$) to a possible cosmologicalvariation of the proton-to-electron mass ratio, $\mu$. Whilst the majority ofcomputed sensitivity coefficients, $T$, involving the low-lying vibrationalstates acquire the expected values of $T\approx-1$ and $T\approx-1/2$ forrotational and ro-vibrational transitions, respectively, anomaloussensitivities are uncovered for the $A_1\!-\!A_2$ splittings in the$\nu_2/\nu_4$, $\nu_1/\nu_3$ and $2\nu_4^{\ell=0}/2\nu_4^{\ell=2}$ manifolds ofPH$_3$. A pronounced Coriolis interaction between these states in conjunctionwith accidentally degenerate $A_1$ and $A_2$ energy levels produces a series ofenhanced sensitivity coefficients. Phosphine is expected to occur in a numberof different astrophysical environments and has potential for investigating adrifting constant. Furthermore, the displayed behaviour hints at a wider trendin molecules of ${\bf C}_{3\mathrm{v}}\mathrm{(M)}$ symmetry, thusdemonstrating that the splittings induced by higher-order ro-vibrationalinteractions are well suited for probing $\mu$ in other symmetric top moleculesin space, since these low-frequency transitions can be straightforwardlydetected by radio telescopes.

Retrieved from arxiv

Retrieved from arxiv

Authors: U. D. Jentschura

Published: Oct 2004

Authors: U. D. Jentschura

Published: Oct 2004

We investigate the gauge invariance of the leading logarithmic radiativecorrection to the two-photon decay width in hydrogenlike atoms. It is shownthat an effective treatment of the correction using a Lamb-shift "potential"leads to equivalent results in both the length as well as the velocity gaugesprovided all relevant correction terms are taken into account. Specifically,the relevant radiative corrections are related to the energies that enter intothe propagator denominators, to the Hamiltonian, to the wave functions, and tothe energy conservation condition that holds between the two photons; the formof all of these effects is different in the two gauges, but the final result isshown to be gauge invariant, as it should be. Although the actual calculationonly involves integrations over nonrelativistic hydrogenic Green functions, thederivation of the leading logarithmic correction can be regarded as slightlymore complex than that of other typical logarithmic terms. The dominantradiative correction to the 2S two-photon decay width is found to be -2.020536(alpha/pi) (Zalpha)^2 ln[(Zalpha)^-2] in units of the leading nonrelativisticexpression. This result is in agreement with a length-gauge calculation [S. G.Karshenboim and V. G. Ivanov, e-print physics/9702027], where the coefficientwas given as -2.025(1).

Retrieved from arxiv

Retrieved from arxiv

Authors: Paul E. Grabowski, David F. Chernoff

Published: Sep 2009

Authors: Paul E. Grabowski, David F. Chernoff

Published: Sep 2009

- nice

Retrieved from arxiv

Retrieved from arxiv

Authors: David Alexander Anderson, Rachel Elizabeth Sapiro, Georg Raithel

Published: Oct 2019

Authors: David Alexander Anderson, Rachel Elizabeth Sapiro, Georg Raithel

Published: Oct 2019

We present a self-calibrating, SI-traceable broadband Rydberg-atom-basedradio-frequency (RF) electric field probe (the Rydberg Field Probe or RFP) andmeasurement instrument (Rydberg Field Measurement System or RFMS). The RFMScomprises an atomic RF field probe (RFP), connected by a ruggedized fiber-opticpatch cord to a portable mainframe control unit with a software interface forRF measurement and analysis including real-time field readout and RF waveformvisualization. The instrument employs electromagnetically induced transparency(EIT) readout of spectral signatures from RF-sensitive Rydberg states of anatomic vapor for continuous, pulsed, and modulated RF field measurement. TheRFP exploits resonant and off-resonant Rydberg-field interactions to realizebroadband RF measurements at frequencies ranging from ~10 MHz to sub-THz over awide dynamic range. The RFMS incorporates an RF-field-free atomic reference anda laser-frequency tracker to ensure reliability and accuracy of the RFmeasurement. We characterize the RFP and measure polar field and polarizationpatterns of the RFP at 12.6 GHz RF in the far-field of a standard gain hornantenna. Measurements at 2.5 GHz are also performed. Measured patterns are ingood agreement with simulations. A detailed calibration procedure anduncertainty analysis are presented that account for deviations from anisotropic response over a $4\pi$ solid angle, arising from dielectricstructures external to the atomic measurement volume. Contributions to themeasurement uncertainty from the fundamental atomic measurement method andassociated analysis as well as material, geometry, and hardware design choicesare accounted for. A calibration (C) factor is used to establishabsolute-standard SI-traceable calibration of the RFP. Pulsed and modulated RFfield measurement, and time-domain RF-pulse waveform imaging are alsodemonstrated.

Retrieved from arxiv

Retrieved from arxiv

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