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Articles 1  30 of 47
FullText Articles in Physical Sciences and Mathematics
TwoLoop Bethe Logarithms For Non S Levels, Ulrich D. Jentschura
TwoLoop Bethe Logarithms For Non S Levels, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
Twoloop Bethe logarithms are calculated for excited P and D states in hydrogenlike systems, and estimates are presented for all states with higher angular momenta. These results complete our knowledge of the P and D energy levels in hydrogen at the order of α^{8} m_{e}c^{2}, where me is the electron mass and c is the speed of light, and scale as Z^{6}, where Z is the nuclear charge number. Our analytic and numerical calculations are consistent with the complete absence of logarithmic terms of order (απ)^{2} (Zα)^{6} ln [(Zα)^{2}] m_{e}c ...
Differential Electron Emission For Single And Multiple Ionization Of Argon By 500 Ev Positrons, Jared M. Gavin, Robert D. Dubois, O. G. De Lucio
Differential Electron Emission For Single And Multiple Ionization Of Argon By 500 Ev Positrons, Jared M. Gavin, Robert D. Dubois, O. G. De Lucio
Physics Faculty Research & Creative Works
Triply differential electron emission cross sections are measured for single ionization of argon by 500 eV positrons. Data are presented for coincidences between projectiles scattered into angles of 3° and electrons with emission energies less than 10 eV that are observed between 45 and 135° along the beam direction. For interpretation, these are compared to cosine squared representations of the binary and recoil lobes which are convoluted over experimental parameters. Singly differential electron emission data for double and triple ionization by positrons are also presented.
K Α₁ Radiation From Heavy, Heliumlike Ions Produced In Relativistic Collisions, Andrey S. Surzhykov, Ulrich D. Jentschura, Th H. Stohlker, Stephan Fritzsche
K Α₁ Radiation From Heavy, Heliumlike Ions Produced In Relativistic Collisions, Andrey S. Surzhykov, Ulrich D. Jentschura, Th H. Stohlker, Stephan Fritzsche
Physics Faculty Research & Creative Works
Boundstate transitions in fewelectron, heavy ions following radiative electron capture are studied within the framework of the density matrix theory and the multiconfiguration DiracFock approach. Special attention is paid to the K α_{1} (1 s_{1/2} 2 p_{3/2} ^{1.3}P_{J=1,2}→1s^{2}_{1/2} ^{1}S_{J=0}) radiative decay of heliumlike uranium U^{90+} projectiles. This decay has recently been observed at the GSI facility in Darmstadt, giving rise to a surprisingly isotropic angular distribution, which is inconsistent with previous experiments and calculations based on a "oneparticle" model. We show that ...
Analysis Of TwoDimensional Photoelectron Momentum Spectra And The Effect Of The LongRange Coulomb Potential In Single Ionization Of Atoms By Intense Lasers, Zhangjin Chen, Toru Morishita, AnhThu Le, M. Wickenhauser, X. M. Tong, C. D. Lin
Analysis Of TwoDimensional Photoelectron Momentum Spectra And The Effect Of The LongRange Coulomb Potential In Single Ionization Of Atoms By Intense Lasers, Zhangjin Chen, Toru Morishita, AnhThu Le, M. Wickenhauser, X. M. Tong, C. D. Lin
Physics Faculty Research & Creative Works
Twodimensional (2D) electron momentum distributions and energy spectra for multiphoton ionization of atoms by intense laser pulses, calculated by solving the timedependent Schrödinger equation (TDSE) for different wavelengths and intensities, are compared to those predicted by the strongfield approximation (SFA). It is shown that the momentum spectra at low energies between the TDSE and SFA are quite different and the differences arise largely from the absence of a longrange Coulomb interaction in the SFA. We further found that the lowenergy 2D momentum spectra from the TDSE exhibit ubiquitous fanlike features where the number of stripes is due to a single ...
Quantum Dot Potentials: Symanzik Scaling, Resurgent Expansions, And Quantum Dynamics, Andrey S. Surzhykov, Michael Lubasch, Jean ZinnJustin, Ulrich D. Jentschura
Quantum Dot Potentials: Symanzik Scaling, Resurgent Expansions, And Quantum Dynamics, Andrey S. Surzhykov, Michael Lubasch, Jean ZinnJustin, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
This article is concerned with a special class of the "doublewell like" potentials that occur naturally in the analysis of finite quantum systems. Special attention is paid, in particular, to the socalled FokkerPlanck potential, which has a particular property: the perturbation series for the groundstate energy vanishes to all orders in the coupling parameter, but the actual groundstate energy is positive and dominated by instanton configurations of the form exp (a g), where a is the instanton action. The instanton effects are most naturally taken into account within the modified BohrSommerfeld quantization conditions whose expansion leads to the generalized perturbative ...
Gravitational Diffraction Radiation, Vitor Cardoso, Marco Cavaglia, Mario Pimenta
Gravitational Diffraction Radiation, Vitor Cardoso, Marco Cavaglia, Mario Pimenta
Physics Faculty Research & Creative Works
We show that if the visible universe is a membrane embedded in a higherdimensional space, particles in uniform motion radiate gravitational waves because of spacetime lumpiness. This phenomenon is analogous to the electromagnetic diffraction radiation of a charge moving near to a metallic grating. In the gravitational case, the role of the metallic grating is played by the inhomogeneities of the extradimensional space, such as a hidden brane. We derive a general formula for gravitational diffraction radiation and apply it to a higherdimensional scenario with flat compact extra dimensions. Gravitational diffraction radiation may carry away a significant portion of the ...
Multiple Scattering Mechanisms In Simultaneous ProjectileElectron And TargetElectron Ejection In H⁻ + He Collisions, Michael Schulz, T. Ferger, Daniel Fischer, R. Moshammer, J. D. Ullrich
Multiple Scattering Mechanisms In Simultaneous ProjectileElectron And TargetElectron Ejection In H⁻ + He Collisions, Michael Schulz, T. Ferger, Daniel Fischer, R. Moshammer, J. D. Ullrich
Physics Faculty Research & Creative Works
We studied simultaneous electron ejection from both collision partners in 200keV H^{}+He collisions in a kinematically complete experiment by measuring the fully momentumanalyzed recoil ions and both active electrons in coincidence. The data were analyzed in terms of Dalitz spectra, in which the momentum exchange between three particles is plotted simultaneously in a single spectrum. We found that the energy transfer occurs predominantly between the active electrons, but most of the momentum is exchanged in elastic scattering between the cores of the collision partners.
Volumes Of Critical Bubbles From The Nucleation Theorem, Gerald Wilemski
Volumes Of Critical Bubbles From The Nucleation Theorem, Gerald Wilemski
Physics Faculty Research & Creative Works
A corollary of the nucleation theorem due to Kashchiev [Nucleation: Basic Theory with Applications (ButterworthHeinemann, Oxford, 2000)] allows the volume V* of a critical bubble to be determined from nucleation rate measurements. The original derivation was limited to onecomponent, ideal gas bubbles with a vapor density much smaller than that of the ambient liquid. Here, an exact result is found for multicomponent, nonideal gas bubbles. Provided a weak density inequality holds, this result reduces to Kashchiev's simple form which thus has a much broader range of applicability than originally expected. Limited applications to droplets are also mentioned, and the ...
Exploring Relativistic ManyBody Recoil Effects In Highly Charged Ions, R. Soria Orts, Zoltan Harman, Jose R. Crespo LopezUrrutia, Anton N. Artemyev, Hjalmar Bruhns, Antonio J. Gonzalez, Ulrich D. Jentschura, Christoph H. Keitel, Alain Lapierre, Vladimir Sergeyevich Mironov, Vladimir M. Shabaev, Hiroyuki Tawara, I. I. Tupitsyn, Joachim Hermann Ullrich, Andrey V. Volotka
Exploring Relativistic ManyBody Recoil Effects In Highly Charged Ions, R. Soria Orts, Zoltan Harman, Jose R. Crespo LopezUrrutia, Anton N. Artemyev, Hjalmar Bruhns, Antonio J. Gonzalez, Ulrich D. Jentschura, Christoph H. Keitel, Alain Lapierre, Vladimir Sergeyevich Mironov, Vladimir M. Shabaev, Hiroyuki Tawara, I. I. Tupitsyn, Joachim Hermann Ullrich, Andrey V. Volotka
Physics Faculty Research & Creative Works
The relativistic recoil effect has been the object of experimental investigations using highly charged ions at the Heidelberg electron beam ion trap. Its scaling with the nuclear charge Z boosts its contribution to a measurable level in the magneticdipole (M1) transitions of B and Belike Ar ions. The isotope shifts of ^{36}Ar versus ^{40}Ar have been detected with subppm accuracy, and the recoil effect contribution was extracted from the 1s^{2}2s^{2}2p ^{2}P_{1/2}^{2}P_{3/2} transition in Ar^{13+} and the 1s^{2}2s2p ^{3}P_{1}^{3}P_{2} transition ...
Hyperspherical CloseCoupling Calculations For ElectronCapture Cross Sections In LowEnergy Ne¹⁰⁺ +H (1s) Collisions, P. Barragan, AnhThu Le, C. D. Lin
Hyperspherical CloseCoupling Calculations For ElectronCapture Cross Sections In LowEnergy Ne¹⁰⁺ +H (1s) Collisions, P. Barragan, AnhThu Le, C. D. Lin
Physics Faculty Research & Creative Works
We present total and partial electroncapture cross sections for Ne¹⁰⁺ +H (1s) collisions at energies from 0.01 eV to 1 keV using the hyperspherical closecoupling method. Good agreements with the previous calculations by the classicaltrajectory MonteCarlo method are found for total capture cross section, but not for partial cross sections, especially below about 200 eV/amu. We found that the total cross section is mainly due to the population of n=7 channels and only at energies above 50 eV/amu n = 5,6 channels begin to contribute to the total cross section.
Quantum Electrodynamic Corrections To The Hyperfine Structure Of Excited S States, Ulrich D. Jentschura, Vladimir A. Yerokhin
Quantum Electrodynamic Corrections To The Hyperfine Structure Of Excited S States, Ulrich D. Jentschura, Vladimir A. Yerokhin
Physics Faculty Research & Creative Works
Statedependent quantum electrodynamic corrections are evaluated for the hyperfine splitting of nS states for arbitrary principal quantum number n. The calculations comprise both the selfenergy and the vacuumpolarization correction of order α(Zα) 2 EF and the recoil correction of order (Zα)^{2} (m/M) E_{F}. Higherorder corrections are summarized and partly reevaluated as well. Accurate predictions for hydrogen hyperfine splitting intervals of nS states with n=2,...,8 are presented. The results obtained are important due to steady progress in hydrogen spectroscopy for transitions involving highly excited S states.
YoungType Interference In (E, 2e) Ionization Of H₂, D. S. MilneBrownlie, Matthew S. Foster, Junfang Gao, B. Lohmann, Don H. Madison
YoungType Interference In (E, 2e) Ionization Of H₂, D. S. MilneBrownlie, Matthew S. Foster, Junfang Gao, B. Lohmann, Don H. Madison
Physics Faculty Research & Creative Works
We have investigated the electron impact single ionization of the hydrogen molecule, with fully determined kinematics. The experimental and theoretical results are compared with He ionization under the same conditions. The results indicate that the ejected electron angular distribution for H_{2} is modified due to Youngtype interference between ionization amplitudes for scattering from the two centers in the hydrogen molecule. The observable result is a suppression of the backward scattering (recoil) peak compared with the binary peak.
PolarizationOperator Approach To ElectronPositron Pair Production In Combined Laser And Coulomb Fields, A. I. Milstein, Carsten Muller, Karen Z. Hatsagortsyan, Ulrich D. Jentschura, Christoph H. Keitel
PolarizationOperator Approach To ElectronPositron Pair Production In Combined Laser And Coulomb Fields, A. I. Milstein, Carsten Muller, Karen Z. Hatsagortsyan, Ulrich D. Jentschura, Christoph H. Keitel
Physics Faculty Research & Creative Works
The optical theorem is applied to the process of electronpositron pair creation in the superposition of a nuclear Coulomb and a strong laser field. We derive representations for the total production rate as twofold integrals, both for circular laser polarization and for the general case of elliptic polarization. Our approach allows us to obtain, by analytical means, the asymptotic behavior of the pair creation rate for various limits of interest. In particular, we consider pair production by twophoton absorption and show that, close to the energetic threshold of this process, the rate obeys a power law in the laser frequency ...
TwoPhoton Excitation Dynamics In Bound TwoBody Coulomb Systems Including Ac Stark Shift And Ionization, Martin K. Haas, Ulrich D. Jentschura, Christoph H. Keitel, Nikolai N. Kolachevsky, Maximilian Herrmann, Peter Fendel, Marc P. Fischer, Th H. Udem, Ronald Holzwarth, Theodor Wolfgang Hansch, Marlan O. Scully, Girish S. Agarwal
TwoPhoton Excitation Dynamics In Bound TwoBody Coulomb Systems Including Ac Stark Shift And Ionization, Martin K. Haas, Ulrich D. Jentschura, Christoph H. Keitel, Nikolai N. Kolachevsky, Maximilian Herrmann, Peter Fendel, Marc P. Fischer, Th H. Udem, Ronald Holzwarth, Theodor Wolfgang Hansch, Marlan O. Scully, Girish S. Agarwal
Physics Faculty Research & Creative Works
One of the dominant systematic effects that shift resonance lines in highprecision measurements of twophoton transitions is the dynamic (ac) Stark shift. For suitable laser frequencies, the ac Stark shift acquires an imaginary part which corresponds to the rate of resonant onephoton ionization of electrons into a continuum state. At the current level of spectroscopic accuracy, the underlying timedependent quantum dynamics governing the atomic twophoton excitation process must be well understood, and related considerations are the subject of the present paper. In order to illustrate the basic mechanisms in the transient regime, we investigate an analytically solvable model scenario for ...
Benchmarking HighField FewElectron Correlation And Qed Contributions In Hg⁷⁵⁺ To Hg⁷⁸⁺ Ions. Ii. Theory, Zoltan Harman, I. I. Tupitsyn, Anton N. Artemyev, Ulrich D. Jentschura, Christoph H. Keitel, Jose R. Crespo LopezUrrutia, Antonio J. Gonzalez, Hiroyuki Tawara, Joachim Hermann Ullrich
Benchmarking HighField FewElectron Correlation And Qed Contributions In Hg⁷⁵⁺ To Hg⁷⁸⁺ Ions. Ii. Theory, Zoltan Harman, I. I. Tupitsyn, Anton N. Artemyev, Ulrich D. Jentschura, Christoph H. Keitel, Jose R. Crespo LopezUrrutia, Antonio J. Gonzalez, Hiroyuki Tawara, Joachim Hermann Ullrich
Physics Faculty Research & Creative Works
Theoretical resonance energies for KLL dielectronic recombination into He, Li, Be, and Blike Hg ions are calculated by various means and discussed in detail. We apply the multiconfiguration DiracFock and the configuration interaction DiracFockSturmian methods, and quantum electrodynamic manybody theory. The different contributions such as relativistic electron interaction, quantum electrodynamic contributions, and finite nuclear size and mass corrections are calculated and their respective theoretical uncertainties are estimated. Our final results are compared to experimental data from the preceding paper. The comparison of theoretical values with the experimental energies shows a good overall agreement for most transitions and illustrates the significance ...
(E,2e) Measurements On Xenon: Reexamination Of The FineStructure Effect, Radmila Panajotovic, Julian C A Lower, Erich Weigold, A. Prideaux, Don H. Madison
(E,2e) Measurements On Xenon: Reexamination Of The FineStructure Effect, Radmila Panajotovic, Julian C A Lower, Erich Weigold, A. Prideaux, Don H. Madison
Physics Faculty Research & Creative Works
The process of electron scattering from heavy target atoms is of considerable interest due to the enhanced role of relativistic effects and distortion of the electron trajectories resulting from the large value of nuclear charge. Here we present (e,2e) ionization measurements and distortedwave Born approximation calculations for the scattering of spinpolarized electrons from xenon atoms in which the finestructure levels of the residual ion are resolved. Comparison of measurements performed using a highsensitivity toroidal analyzer spectrometer with the predictions of sophisticated calculations provide an improved understanding of the ionization dynamics of heavy target atoms and the treatment of electron ...
Benchmarking HighField FewElectron Correlation And Qed Contributions In Hg⁷⁵⁺ To Hg⁷⁸⁺ Ions. I. Experiment, Antonio J. Gonzalez, Jose R. Crespo LopezUrrutia, Jean Pierre Braun, Gunter Brenner, Hjalmar Bruhns, Alain Lapierre, Vladimir Sergeyevich Mironov, R. Soria Orts, Hiroyuki Tawara, Michael Trinczek, Joachim Hermann Ullrich, Anton N. Artemyev, Zoltan Harman, Ulrich D. Jentschura, Christoph H. Keitel, James H. Scofield, I. I. Tupitsyn
Benchmarking HighField FewElectron Correlation And Qed Contributions In Hg⁷⁵⁺ To Hg⁷⁸⁺ Ions. I. Experiment, Antonio J. Gonzalez, Jose R. Crespo LopezUrrutia, Jean Pierre Braun, Gunter Brenner, Hjalmar Bruhns, Alain Lapierre, Vladimir Sergeyevich Mironov, R. Soria Orts, Hiroyuki Tawara, Michael Trinczek, Joachim Hermann Ullrich, Anton N. Artemyev, Zoltan Harman, Ulrich D. Jentschura, Christoph H. Keitel, James H. Scofield, I. I. Tupitsyn
Physics Faculty Research & Creative Works
The photorecombination of highly charged fewelectron mercury ions Hg^{75+} to Hg^{78+} has been explored with the Heidelberg electron beam ion trap. By monitoring the emitted x rays (6576 keV) and scanning the electron beam energy (4554 keV) over the KLL dielectronic recombination (DR) region, the energies of stateselected DR resonances were determined to within ±4 eV (relative) and ±14 eV (absolute). At this level of experimental accuracy, it becomes possible to make a detailed comparison to various theoretical approaches and methods, all of which include quantum electrodynamic (QED) effects and finite nuclear size contributions (for a 1s electron ...
Evidence Of TwoCenter Interference In HighOrder Harmonic Generation From Co₂, AnhThu Le, XiaoMin Tong, C. D. Lin
Evidence Of TwoCenter Interference In HighOrder Harmonic Generation From Co₂, AnhThu Le, XiaoMin Tong, C. D. Lin
Physics Faculty Research & Creative Works
Two recent pumpprobe experiments on the highorder harmonic generation (HHG) from partially aligned CO₂ molecules have shown that the HHG yields versus the ionization rates as functions of the pumpprobe delay time exhibit inverted modulation. The inversion has been attributed to the quantum interference in the recombination process from the two oxygen centers. Using the Lewenstein model to calculate HHG from fixed CO₂ molecules and taking into account the partial alignment of the molecules versus the time delay, we interpret that the inversion is due to the degree of overlap between the partially aligned molecules and the angular dependence of ...
Radiative Electron Capture Into High Z FewElectron Ions: Alignment Of The Excited Ionic States, Andrey S. Surzhykov, Ulrich D. Jentschura, Th H. Stohlker, Stephan Fritzsche
Radiative Electron Capture Into High Z FewElectron Ions: Alignment Of The Excited Ionic States, Andrey S. Surzhykov, Ulrich D. Jentschura, Th H. Stohlker, Stephan Fritzsche
Physics Faculty Research & Creative Works
We lay out a unified formalism for the description of radiative electron capture into excited states of heavy, fewelectron ions and their subsequent decay, including a full account of manyelectron effects and higherorder multipoles of the radiation field. In particular, the densitymatrix theory is applied to explore the magnetic sublevel population of the residual ions, as described in terms of alignment parameters. For the electron capture into the initially hydrogenlike U^{91+} and lithiumlike U^{89+} uranium projectiles, the alignment parameters are calculated, within the multiconfiguration DiracFock approach, as a function of the collision energy and for different ionic states ...
Modeling Study Of The DipHump Feature In Bi₂ Sr₂ Cacu₂ O_{8+Δ} Tunneling Spectroscopy, Pierom Romano, Lutfi Ozyuzer, Zikri M. Yusof, Cihan Kurter, John F. Zasadzinski
Modeling Study Of The DipHump Feature In Bi₂ Sr₂ Cacu₂ O8+Δ Tunneling Spectroscopy, Pierom Romano, Lutfi Ozyuzer, Zikri M. Yusof, Cihan Kurter, John F. Zasadzinski
Physics Faculty Research & Creative Works
The tunneling spectra of hightemperature superconductors on Bi_{2} Sr_{2} CaCu_{2} O_{8+δ} (Bi2212) reproducibly show a highbias structure in the form of a diphump at voltages higher than the gap voltage. Of central concern is whether this feature originates from the normal state background or is intrinsic to the superconducting mechanism. We address this issue by generating a set of model conductance curvesa "normal state" conductance that takes into account effects such as the band structure and a possible pseudogap, and a pure superconducting state conductance. When combined, the result shows that the diphump feature present ...
XRay Emission Cross Sections Following Charge Exchange By Multiply Charged Ions Of Astrophysical Interest, Sebastian Otranto, Ronald E. Olson, P. Beiersdorfer
XRay Emission Cross Sections Following Charge Exchange By Multiply Charged Ions Of Astrophysical Interest, Sebastian Otranto, Ronald E. Olson, P. Beiersdorfer
Physics Faculty Research & Creative Works
State selective nlelectron capture cross sections are presented for highly charged ions with Z=610 colliding with atoms and molecules. The energy range investigated was from 1 eV/amu(v=0.006 a.u.)to 100 keV/amu(v=2.0 a.u.). The energy dependence of the llevel populations is investigated. The K shell xray emission cross sections are determined by using the calculated stateselective electron capture results as input and then applying hydrogenic branching and cascading values for the photon emission. A major shift in the line emission from being almost solely Lymanalpha transitions at the highest collisions ...
Simulations Of Black Hole Air Showers In Cosmic Ray Detectors, EunJoo Ahn, Marco Cavaglia
Simulations Of Black Hole Air Showers In Cosmic Ray Detectors, EunJoo Ahn, Marco Cavaglia
Physics Faculty Research & Creative Works
We present a comprehensive study of TeV black hole events in Earth's atmosphere originated by cosmic rays of very high energy. An advanced fortran Monte Carlo code is developed and used to simulate black hole extensive air showers from ultrahighenergy neutrinonucleon interactions. We investigate the characteristics of these events, compare the black hole air showers to standard model air showers, and test different theoretical and phenomenological models of black hole formation and evolution. The main features of black hole air showers are found to be independent of the model considered. No significant differences between models are likely to be ...
Black Hole Particle Emission In HigherDimensional Spacetimes, Vitor Cardoso, Marco Cavaglia, Leonardo Gualtieri
Black Hole Particle Emission In HigherDimensional Spacetimes, Vitor Cardoso, Marco Cavaglia, Leonardo Gualtieri
Physics Faculty Research & Creative Works
In models with extra dimensions, a black hole evaporates both in the bulk and on the visible brane, where standard model fields live. The exact emissivities of each particle species are needed to determine how the black hole decay proceeds. We compute and discuss the absorption cross sections, the relative emissivities, and the total power output of all known fields in the evaporation phase. Graviton emissivity is highly enhanced as the spacetime dimensionality increases. Therefore, a black hole loses a significant fraction of its mass in the bulk. This result has important consequences for the phenomenology of black holes in ...
ƑElectron Correlations In Nonmagnetic Ce Studied By Means Of SpinResolved Resonant Photoemission, S. W. Yu, Takashi Komesu, B. W. Chung, Simon A. Morton, James G. Tobin, George Daniel Waddill
ƑElectron Correlations In Nonmagnetic Ce Studied By Means Of SpinResolved Resonant Photoemission, S. W. Yu, Takashi Komesu, B. W. Chung, Simon A. Morton, James G. Tobin, George Daniel Waddill
Physics Faculty Research & Creative Works
We have studied the spinspin coupling between two f electrons of nonmagnetic Ce by means of spinresolved resonant photoemission using circularly polarized synchrotron radiation. The two f electrons participating in the 3d5/2>4f resonance process are coupled in a singlet while the coupling is veiled in the 3d3/2>4f process due to an additional CosterKronig decay channel. The identical singlet coupling is observed in the 4d>4f resonance process. Based on the Ce measurements, it is argued that spinresolved resonant photoemission is one approach to study the correlation effects, particularly in the form of spin, in the rare ...
Erratum: Black Hole Particle Emission In HigherDimensional Spacetimes (Physical Review Letters (2006) 96 (071301)), Vitor Cardoso, Marco Cavaglia, Leonardo Gualtieri
Erratum: Black Hole Particle Emission In HigherDimensional Spacetimes (Physical Review Letters (2006) 96 (071301)), Vitor Cardoso, Marco Cavaglia, Leonardo Gualtieri
Physics Faculty Research & Creative Works
No abstract provided.
Magnetically Mediated Transparent Conductors: In₂O₃ Doped With Mo, Julia E. Medvedeva
Magnetically Mediated Transparent Conductors: In₂O₃ Doped With Mo, Julia E. Medvedeva
Physics Faculty Research & Creative Works
Firstprinciples band structure investigations of the electronic, optical, and magnetic properties of Modoped In2O3 reveal the vital role of magnetic interactions in determining both the electrical conductivity and the BursteinMoss shift which governs optical absorption. We demonstrate the advantages of the transition metal doping which results in smaller effective mass, larger fundamental band gap, and better overall optical transmission in the visible as compared to commercial Sndoped In2O3. Similar behavior is expected upon doping with other transition metals opening up an avenue for the family of efficient transparent conductors mediated by magnetic interactions.
Kinetic Correlation In PhotoDoubleIonization Processes: The HeIsoelectronic Sequence, Sebastian Otranto, C. R. Garibotti
Kinetic Correlation In PhotoDoubleIonization Processes: The HeIsoelectronic Sequence, Sebastian Otranto, C. R. Garibotti
Physics Faculty Research & Creative Works
Analytical models proposed to represent the twoelectron continuum are revisited. Main results obtained with these models are summarized. Recent studies of the photodoubleionization (PDI) of the Heisoelectronic sequence by means of the recently introduced SC3 model are shown and compared with the results predicted by classical and semiclassical Wannier approaches. By fitting the triply differential cross sections (TDCSs) with the usual dipolar Gaussian form we find that the width has a power dependence on excess energy with exponent 0.25 in the near threshold region and departs from this law with increasing energy
Quantum Phase Transitions Of The Diluted O(3) Rotor Model, Thomas Vojta, Rastko Sknepnek
Quantum Phase Transitions Of The Diluted O(3) Rotor Model, Thomas Vojta, Rastko Sknepnek
Physics Faculty Research & Creative Works
We study the phase diagram and the quantum phase transitions of a sitediluted twodimensional O(3) quantum rotor model by means of largescale Monte Carlo simulations. This system has two quantum phase transitions: a generic one for small dilutions and a percolation transition across the lattice percolation threshold. We determine the critical behavior for both transitions and for the multicritical point that separates them. In contrast to the exotic scaling scenarios found in other random quantum systems, all these transitions are characterized by finitedisorder fixed points with powerlaw scaling. We relate our findings to a recent classification of phase transitions ...
Spin Excitations In Fluctuating Stripe Phases Of Doped Cuprate Superconductors, Matthias Vojta, Thomas Vojta, Ribhu K. Kaul
Spin Excitations In Fluctuating Stripe Phases Of Doped Cuprate Superconductors, Matthias Vojta, Thomas Vojta, Ribhu K. Kaul
Physics Faculty Research & Creative Works
Using a phenomenological lattice model of coupled spin and charge modes, we determine the spin susceptibility in the presence of fluctuating stripe charge order. We assume the charge fluctuations to be slow compared to those of the spins, and combine Monte Carlo simulations for the charge order parameter with exact diagonalization of the spin sector. Our calculations unify the spin dynamics of both static and fluctuating stripe phases and support the notion of a universal spin excitation spectrum in doped cuprate superconductors.
SelfOptimization Of Optical Confinement In An Ultraviolet Photonic Crystal Slab Laser, Alexey Yamilov, X. Wu, X. Liu, Hui Cao, Robert P. H. Chang
SelfOptimization Of Optical Confinement In An Ultraviolet Photonic Crystal Slab Laser, Alexey Yamilov, X. Wu, X. Liu, Hui Cao, Robert P. H. Chang
Physics Faculty Research & Creative Works
We studied numerically and experimentally the effects of structural disorder on the performance of ultraviolet photonic crystal slab lasers. Optical gain selectively amplifies the highquality modes of the passive system. For these modes, the inplane and outofplane leakage rates may be automatically balanced in the presence of disorder. The spontaneous optimization of inplane and outofplane confinement of light in a photonic crystal slab may lead to a reduction of the lasing threshold.