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 Quantum electrodynamics (3)
 Quantum mechanics (3)
 Stochastic electrodynamics (3)
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 Harmonic oscillator (2)

 KapitzaDirac effect (2)
 Parametric excitation (2)
 Zeropoint radiation (2)
 Decoding transition (1)
 Electron pulse (1)
 Coherence (1)
 AharonovBohm (1)
 Electronphonon coupling (1)
 Electromagnetic momentum (1)
 Heisenberg (1)
 Fermi surface nesting (1)
 Erasure correction (1)
 Ising (1)
 Distance verification (1)
 KapitzaDirac Effect (1)
 Diffraction (1)
 Electrons (1)
 Derivations (1)
 Functional Analysis (1)
 Interference pattern (1)
 Degeneracy (1)
 Classical relativistic dynamics (1)
 Femtosecond laser (1)
 LDPC codes (1)
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Articles 1  24 of 24
FullText Articles in Physics
Unbounded Derivations Of C*Algebras And The Heisenberg Commutation Relation, Lara M. Ismert
Unbounded Derivations Of C*Algebras And The Heisenberg Commutation Relation, Lara M. Ismert
Dissertations, Theses, and Student Research Papers in Mathematics
This dissertation investigates the properties of unbounded derivations on C*algebras, namely the density of their analytic vectors and a property we refer to as "kernel stabilization." We focus on a weaklydefined derivation δ_{D} which formalizes commutators involving unbounded selfadjoint operators on a Hilbert space. These commutators naturally arise in quantum mechanics, as we briefly describe in the introduction.
A first application of kernel stabilization for δ_{D} shows that a large class of abstract derivations on unbounded C*algebras, defined by O. Bratteli and D. Robinson, also have kernel stabilization. A second application of kernel stabilization provides a ...
Free Electron Sources And Diffraction In Time, Eric R. Jones
Free Electron Sources And Diffraction In Time, Eric R. Jones
Theses, Dissertations, and Student Research: Department of Physics and Astronomy
The quantum revolution of the last century advanced synergistically with technology, for example, with control of the temporal and spatial coherence, and the polarization state of light. Indeed, experimental confirmation of the quirks of quantum theory, as originally highlighted by Einstein, Podolsky, and Rosen, through Bohm, and then Bell, have been performed with photons, i.e., electromagnetic wave packets prepared in the same quantum states. Experimental tests of quantum mechanics with matter wave packets have been limited due to challenges in preparing all of the packets with similar quantum states. While great strides have been made for trapped atoms and ...
Testing Quantum Coherence In Stochastic Electrodynamics With Squeezed Schrödinger Cat States, Wayne ChengWei Huang, Herman Batelaan
Testing Quantum Coherence In Stochastic Electrodynamics With Squeezed Schrödinger Cat States, Wayne ChengWei Huang, Herman Batelaan
Faculty Publications, Department of Physics and Astronomy
The interference pattern in electron doubleslit diffraction is a hallmark of quantum mechanics. A longstanding question for stochastic electrodynamics (SED) is whether or not it is capable of reproducing such effects, as interference is a manifestation of quantum coherence. In this study, we used excited harmonic oscillators to directly test this quantum feature in SED. We used two counterpropagating dichromatic laser pulses to promote a groundstate harmonic oscillator to a squeezed Schrödinger cat state. Upon recombination of the two wellseparated wavepackets, an interference pattern emerges in the quantum probability distribution but is absent in the SED probability distribution. We thus ...
Numerical And Analytical Bounds On Threshold Error Rates For HypergraphProduct Codes, Alexey Kovalev, Sanjay Prabhakar, Ilya Dumer, Leonid P. Pryadko
Numerical And Analytical Bounds On Threshold Error Rates For HypergraphProduct Codes, Alexey Kovalev, Sanjay Prabhakar, Ilya Dumer, Leonid P. Pryadko
Faculty Publications, Department of Physics and Astronomy
We study analytically and numerically decoding properties of finiterate hypergraphproduct quantum low density paritycheck codes obtained from random (3,4)regular Gallager codes, with a simple model of independent X and Z errors. Several nontrivial lower and upper bounds for the decodable region are constructed analytically by analyzing the properties of the homological difference, equal minus the logarithm of the maximumlikelihood decoding probability for a given syndrome. Numerical results include an upper bound for the decodable region from specific heat calculations in associated Ising models and a minimumweight decoding threshold of approximately 7%.
Distance Verification For Classical And Quantum Ldpc Codes, Ilya Dumer, Alexey Kovalev, Leonid P. Pryadko
Distance Verification For Classical And Quantum Ldpc Codes, Ilya Dumer, Alexey Kovalev, Leonid P. Pryadko
Faculty Publications, Department of Physics and Astronomy
The techniques of distance verification known for general linear codes are first applied to the quantum stabilizer codes. Then, these techniques are considered for classical and quantum (stabilizer) lowdensityparitycheck (LDPC) codes. New complexity bounds for distance verification with provable performance are derived using the average weight spectra of the ensembles of LDPC codes. These bounds are expressed in terms of the erasurecorrecting capacity of the corresponding ensemble. We also present a new irreduciblecluster technique that can be applied to any LDPC code and takes advantage of paritychecks’ sparsity for both the classical and quantum LDPC codes. This technique reduces complexity ...
TwoColor Multiphoton Emission From Nanotips, Wayne ChengWei Huang, Maria Becker, Joshua Beck, Herman Batelaan
TwoColor Multiphoton Emission From Nanotips, Wayne ChengWei Huang, Maria Becker, Joshua Beck, Herman Batelaan
Faculty Publications, Department of Physics and Astronomy
Twocolor multiphoton emission from polycrystalline tungsten nanotips has been demonstrated using twocolor laser fields. The twocolor photoemission is assisted by a threephoton multicolor quantum channel, which leads to a twofold increase in quantum efficiency. Weakfield control of two color multiphoton emission was achieved by changing the efficiency of the quantum channel with pulse delay. The result of this study complements twocolor tunneling photoemission in strong fields, and has potential applications for nanowirebased photonic devices. Moreover, the demonstrated twocolor multiphoton emission may be important for realizing ultrafast spinpolarized electron sources via optically injected spin current.
On The Ising Character Of The QuantumPhase Transition In Lihof_{4}, Ralph Skomski
On The Ising Character Of The QuantumPhase Transition In Lihof4, Ralph Skomski
Ralph Skomski Publications
It is investigated how a transverse magnetic field affects the quantummechanical character of LiHoF_{4}, a system generally considered as a textbook example for an Isinglike quantumphase transition. In small magnetic fields, the lowtemperature behavior of the ions is Isinglike, involving the nearly degenerate lowlying J_{z} = ± 8 doublet. However, as the transverse field increases, there is a substantial admixture of states having  J_{z}  < 8. Near the quantumphasetransition field, the system is distinctively nonIsing like, and all J_{z} eigenstates yield groundstate contributions of comparable magnitude. A classical analog to this mechanism is the micromagnetic single point in magnets with uniaxial anisotropy. Since Ho^{3}^{+} has J = 8, the ion’s behavior ...
Event Generator Tunes Obtained From Underlying Event And Multiparton Scattering Measurements, Cms Collaboration, Ekaterina Cms Avdeeva, Kenneth A. Bloom, S. Bose, Daniel Claes, Aaron Dominguez, Caleb Fangmeier, Rebeca Gonzalez Suarez, Rami Kamalieddin, J. Keller, D. Knowlton, Ilya Kravchenko, F. Meier, Jose Monroy, F. Ratnikov, J. E. Siado, Gregory Snow
Event Generator Tunes Obtained From Underlying Event And Multiparton Scattering Measurements, Cms Collaboration, Ekaterina Cms Avdeeva, Kenneth A. Bloom, S. Bose, Daniel Claes, Aaron Dominguez, Caleb Fangmeier, Rebeca Gonzalez Suarez, Rami Kamalieddin, J. Keller, D. Knowlton, Ilya Kravchenko, F. Meier, Jose Monroy, F. Ratnikov, J. E. Siado, Gregory Snow
Kenneth Bloom Publications
New sets of parameters (“tunes”) for the underlyingevent (UE) modelling of the PYTHIA8, PYTHIA6 and HERWIG++ MonteCarlo event generators are constructed using different parton distribution functions. Combined fits to CMS UE proton–proton (pp) data at √s = 7 TeV and to UE proton–antiproton (pp) data from the CDF experiment at lower √s, are used to study the UE models and constrain their parameters, providing thereby improved predictions for proton–proton collisions at 13 TeV. In addition, it is investigated whether the values of the parameters obtained from fits to UE observables are consistent with the values determined from fitting ...
Measurement Of The Differential Cross Section And Charge Asymmetry For Inclusive Pp → W^{±} + X Production At √S = 8 Tev, Ekaterina Avdeeva, Rachel Bartek, Kenneth A. Bloom, Suvadeep Bose, Daniel R. Claes, Aaron Dominguez, Caleb Fangmeier, Rebeca Gonzalez Suarez, Rami Kamalieddin, Daniel Knowlton, Ilya Kravchenko, Jose Monroy, F. Meier, F. Ratnikov, J. E. Siado, Gregory Snow, B. Stieger, Cms Collaboration
Measurement Of The Differential Cross Section And Charge Asymmetry For Inclusive Pp → W± + X Production At √S = 8 Tev, Ekaterina Avdeeva, Rachel Bartek, Kenneth A. Bloom, Suvadeep Bose, Daniel R. Claes, Aaron Dominguez, Caleb Fangmeier, Rebeca Gonzalez Suarez, Rami Kamalieddin, Daniel Knowlton, Ilya Kravchenko, Jose Monroy, F. Meier, F. Ratnikov, J. E. Siado, Gregory Snow, B. Stieger, Cms Collaboration
Faculty Publications, Department of Physics and Astronomy
The differential cross section and charge asymmetry for inclusive pp → W^{±} + X → μ^{±}ν + X production at √s = 8 TeV are measured as a function of muon pseudorapidity. The data sample corresponds to an integrated luminosity of 18.8 fb^{−1} recorded with the CMS detector at the LHC. These results provide important constraints on the parton distribution functions of the proton in the range of the Bjorken scaling variable x from 10^{−3} to 10^{−1}.
Momentum Exchange In The Electron DoubleSlit Experiment, Herman Batelaan, Eric Jones, Wayne ChengWei Huang, Roger Bach
Momentum Exchange In The Electron DoubleSlit Experiment, Herman Batelaan, Eric Jones, Wayne ChengWei Huang, Roger Bach
Faculty Publications, Department of Physics and Astronomy
We provide support for the claim that momentum is conserved for individual events in the electron double slit experiment. The natural consequence is that a physical mechanism is responsible for this momentum exchange, but that even if the fundamental mechanism is known for electron crystal diffraction and the Kapitza–Dirac effect, it is unknown for electron diffraction from nanofabricated double slits. Work towards a proposed explanation in terms of particle trajectories affected by a vacuum field is discussed. The contentious use of trajectories is discussed within the context of oil droplet analogues of double slit diffraction.
SpinDependent TwoColor KapitzaDirac Effects, Scot Mcgregor, Wayne ChengWei Huang, Herman Batelaan, Bradley Allan Shadwick
SpinDependent TwoColor KapitzaDirac Effects, Scot Mcgregor, Wayne ChengWei Huang, Herman Batelaan, Bradley Allan Shadwick
Faculty Publications, Department of Physics and Astronomy
In this paper we present an analysis of the spin behavior of electrons propagating through a laser field. We present an experimentally realizable scenario in which spindependent effects of the interaction between the laser and the electrons are dominant. The laser interaction strength and incident electron velocity are in the nonrelativistic domain. This analysis may thus lead to novel methods of creating and characterizing spinpolarized nonrelativistic femtosecond electron pulses.
Discrete Excitation Spectrum Of A Classical Harmonic Oscillator In ZeroPoint Radiation, Wayne ChengWei Huang, Herman Batelaan
Discrete Excitation Spectrum Of A Classical Harmonic Oscillator In ZeroPoint Radiation, Wayne ChengWei Huang, Herman Batelaan
Faculty Publications, Department of Physics and Astronomy
We report that upon excitation by a single pulse, a classical harmonic oscillator immersed in the classical electromagnetic zeropoint radiation exhibits a discrete harmonic spectrum in agreement with that of its quantum counterpart. This result is interesting in view of the fact that the vacuum field is needed in the classical calculation to obtain the agreement.
Thresholds For Correcting Errors, Erasures, And Faulty Syndrome Measurements In Degenerate Quantum Codes, Ilya Dumer, Alexey Kovalev, Leonid P. Pryadko
Thresholds For Correcting Errors, Erasures, And Faulty Syndrome Measurements In Degenerate Quantum Codes, Ilya Dumer, Alexey Kovalev, Leonid P. Pryadko
Faculty Publications, Department of Physics and Astronomy
We suggest a technique for constructing lower (existence) bounds for the faulttolerant threshold to scalable quantum computation applicable to degenerate quantum codes with sublinear distance scaling. We give explicit analytic expressions combining probabilities of erasures, depolarizing errors, and phenomenological syndrome measurement errors for quantum lowdensity paritycheck codes with logarithmic or larger distances. These threshold estimates are parametrically better than the existing analytical bound based on percolation.
Spin Glass Reflection Of The Decoding Transition For Quantum Error Correcting Codes, Alexey Kovalev, Leonid P. Pryadko
Spin Glass Reflection Of The Decoding Transition For Quantum Error Correcting Codes, Alexey Kovalev, Leonid P. Pryadko
Faculty Publications, Department of Physics and Astronomy
We study the decoding transition for quantum error correcting codes with the help of a mapping to randombond Wegner spin models. Families of quantum low density paritycheck (LDPC) codes with a finite decoding threshold lead to both known models (e.g., random bond Ising and random plaquette Z_{2} gauge models) as well as unexplored earlier generally nonlocal disordered spin models with nontrivial phase diagrams. The decoding transition corresponds to a transition from the ordered phase by proliferation of "posttopological" extended defects which generalize the notion of domain walls to nonlocal spin models. In recently discovered quantum LDPC code families ...
Parafermion Stabilizer Codes, Utkan Güngördü, Rabindra Nepal, Alexey Kovalev
Parafermion Stabilizer Codes, Utkan Güngördü, Rabindra Nepal, Alexey Kovalev
Faculty Publications, Department of Physics and Astronomy
We define and study parafermion stabilizer codes, which can be viewed as generalizations of Kitaev’s onedimensional (1D) model of unpaired Majorana fermions. Parafermion stabilizer codes can protect against lowweight errors acting on a small subset of parafermion modes in analogy to qudit stabilizer codes. Examples of several smallest parafermion stabilizer codes are given. A localitypreserving embedding of qudit operators into parafermion operators is established that allows one to map known qudit stabilizer codes to parafermion codes. We also present a local 2D parafermion construction that combines topological protection of Kitaev’s toric code with additional protection relying on parity ...
Numerical Techniques For Finding The Distances Of Quantum Codes, Ilya Dumer, Alexey Kovalev, Leonid P. Pryadko
Numerical Techniques For Finding The Distances Of Quantum Codes, Ilya Dumer, Alexey Kovalev, Leonid P. Pryadko
Faculty Publications, Department of Physics and Astronomy
We survey the existing techniques for calculating code distances of classical codes and apply these techniques to generic quantum codes. For classical and quantum LDPC codes, we also present a new linkedcluster technique. It reduces complexity exponent of all existing deterministic techniques designed for codes with small relative distances (which include all known families of quantum LDPC codes), and also surpasses the probabilistic technique for sufficiently high code rates.
Demonstrating Entanglement By Testing Bell's Theorem In Majorana Wires, David E. Drummond, Alexey Kovalev, ChangYu Hou, Kirill Shtengel, Leonid P. Pryadko
Demonstrating Entanglement By Testing Bell's Theorem In Majorana Wires, David E. Drummond, Alexey Kovalev, ChangYu Hou, Kirill Shtengel, Leonid P. Pryadko
Faculty Publications, Department of Physics and Astronomy
We propose an experiment that would establish the entanglement of Majorana zero modes in semiconductor nanowires by testing the Bell and ClauserHorneShimonyHolt inequalities. Our proposal is viable with realistic system parameters, simple “keyboard” gating, and projective measurement. Theoretical models and simulation results indicate entanglement can be demonstrated with moderately accurate gate operations. In addition to providing further evidence for the existence of the Majorana bound states, our proposal could be used as an experimental stepping stone to more complicated braiding experiments.
Dynamics Underlying The Gaussian Distribution Of The Classical Harmonic Oscillator In ZeroPoint Radiation, Wayne ChengWei Huang, Herman Batelaan
Dynamics Underlying The Gaussian Distribution Of The Classical Harmonic Oscillator In ZeroPoint Radiation, Wayne ChengWei Huang, Herman Batelaan
Faculty Publications, Department of Physics and Astronomy
Stochastic electrodynamics (SED) predicts a Gaussian probability distribution for a classical harmonic oscillator in the vacuum field. This probability distribution is identical to that of the ground state quantum harmonic oscillator. Thus, the Heisenberg minimum uncertainty relation is recovered in SED. To understand the dynamics that give rise to the uncertainty relation and the Gaussian probability distribution, we perform a numerical simulation and follow the motion of the oscillator. The dynamical information obtained through the simulation provides insight to the connection between the classic doublepeak probability distribution and the Gaussian probability distribution. A main objective for SED research is to ...
ElectronPhonon Coupling And Structural Phase Transitions On Au/Mo(112), Keisuke Fukutani
ElectronPhonon Coupling And Structural Phase Transitions On Au/Mo(112), Keisuke Fukutani
Theses, Dissertations, and Student Research: Department of Physics and Astronomy
The electronic structures, manybody interactions and Fermi surface topologies of Au/Mo(112) were investigated in detail and were found to play important roles in the newly discovered orderdisorder structural phase transition of the system. First, the highresolution angleresolved photoemission spectroscopy was utilized to characterize the electronic band structure of Mo(112) in far greater details than before. This elucidated the existence of several surfacederived states and their dispersion relations in high precisions near the Fermi level, as well as the symmetries of the bulk and surface electronic states, which are in good quantitative agreement with the abinitio calculations. Such ...
Feynman’S Relativistic Electrodynamics Paradox And The AharonovBohm Effect, Adam Caprez, Herman Batelaan
Feynman’S Relativistic Electrodynamics Paradox And The AharonovBohm Effect, Adam Caprez, Herman Batelaan
Faculty Publications, Department of Physics and Astronomy
An analysis is done of a relativistic paradox posed in the Feynman Lectures of Physics involving two interacting charges. The physical system presented is compared with similar systems that also lead to relativistic paradoxes. The momentum conservation problem for these systems is presented. The relation between the presented analysis and the ongoing debates on momentum conservation in the AharonovBohm problem is discussed.
A Macroscopic Test Of The AharonovBohm Effect, Adam Caprez, Brett E. Barwick, Herman Batelaan
A Macroscopic Test Of The AharonovBohm Effect, Adam Caprez, Brett E. Barwick, Herman Batelaan
Faculty Publications, Department of Physics and Astronomy
The AharonovBohm (AB) effect is a purely quantum mechanical effect. The original (classified as TypeI) ABphase shift exists in experimental conditions where the electromagnetic fields and forces are zero. It is the absence of forces that makes the ABeffect entirely quantum mechanical. Although the ABphase shift has been demonstrated unambiguously, the absence of forces in TypeI ABeffects has never been shown. Here, we report the observation of the absence of time delays associated with forces of the magnitude needed to explain the ABphase shift for a macroscopic system.
Electrons, Stern–Gerlach Magnets, And Quantum Mechanical Propagation, Herman Batelaan
Electrons, Stern–Gerlach Magnets, And Quantum Mechanical Propagation, Herman Batelaan
Faculty Publications, Department of Physics and Astronomy
Quantum corrections to Newton’s equations are obtained and used to illustrate that classical dynamics is embedded explicitly in quantum dynamics. Originally, the resultant set of dynamical equations has been used to shed light on quantum chaos. We show that the method can provide insight into the dynamics of free particles and the harmonic oscillator. We then use it to determine whether Stern–Gerlach magnets can be constructed for free electrons.
Phase And Absorption Gratings For Electrons, Hong Gao, Glen Gronniger, Daniel Friemund, Alex Cronin
Phase And Absorption Gratings For Electrons, Hong Gao, Glen Gronniger, Daniel Friemund, Alex Cronin
Faculty Publications, Department of Physics and Astronomy
We report the experimental realization of phase and absorption gratings for electrons. Phase gratings made with standing waves of light with a periodicity of 266 nm are used to diffract 380 eV electrons [1]. Material gratings of 100 and 200 nm periodicity are used to diffract 500 eV electrons. We are exploring the possibility to use these gratings for low energy electron interferometry.
Observation Of The KapitzaDirac Effect, Daniel L. Freimund, Kayvan Aflatooni, Herman Batelaan
Observation Of The KapitzaDirac Effect, Daniel L. Freimund, Kayvan Aflatooni, Herman Batelaan
Faculty Publications, Department of Physics and Astronomy
In their famous 1927 experiment, Davisson and Germer observed the diffraction of electrons by a periodic material structure, so showing that electrons can behave like waves. Shortly afterwards, Kapitza and Dirac predicted that electrons should also be diffracted by a standing light wave. This KapitzaDirac effect is analogous to the diffraction of light by a grating, but with the roles of the wave and matter reversed. The electron and the light grating interact extremely weakly, via the ‘ponderomotive potential,’ so attempts to measure the KapitzaDirac effect had to wait for the development of the laser. The idea that the underlying ...