Quantum Physics Commons^™

Measurement Of The Deuteron Structure Function F₂ In The Resonance Region And Evaluation Of Its Moments, H. Bagdasaryan, S. Bültmann, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, G. Gavalian, N. Guler, C. E. Hyde-Wright, H. G. Juengst, S. E. Kuhn, L. B. Weinstein, J. Yun, Et Al., Clas Collaboration

Physics Faculty Publications

Inclusive electron scattering off the deuteron has been measured to extract the deuteron structure function F₂ with the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. The measurement covers the entire resonance region from the quasielastic peak up to the invariant mass of the final-state hadronic system W similar or equal to 2.7 GeV with four-momentum transfers Q² from 0.4 to 6 (GeV/c)². These data are complementary to previous measurements of the proton structure function F₂ and cover a similar two-dimensional region of Q² and Bjorken variable x. Determination of …

High-Energy Effective Action From Scattering Of Qcd Shock Waves, Ian Balitsky

Physics Faculty Publications

At high energies, the relevant degrees of freedom are Wilson lines--infinite gauge links ordered along straight lines collinear to the velocities of colliding particles. The effective action for these Wilson lines is determined by the scattering of QCD shock waves. I develop the symmetric expansion of the effective action in powers of strength of one of the shock waves and calculate the leading term of the series. The corresponding first-order effective action, symmetric with respect to projectile and target, includes both up and down fan diagrams and pomeron loops

Quantum Dynamics As An Analog Of Conditional Probability, Matthew S. Leifer

Mathematics, Physics, and Computer Science Faculty Articles and Research

Quantum theory can be regarded as a noncommutative generalization of classical probability. From this point of view, one expects quantum dynamics to be analogous to classical conditional probabilities. In this paper, a variant of the well-known isomorphism between completely positive maps and bipartite density operators is derived, which makes this connection much more explicit. This isomorphism is given an operational interpretation in terms of statistical correlations between ensemble preparation procedures and outcomes of measurements. Finally, the isomorphism is applied to elucidate the connection between no-cloning and no-broadcasting theorems and the monogamy of entanglement, and a simplified proof of the no-broadcasting …

Conditional Density Operators And The Subjectivity Of Quantum Operations, Matthew S. Leifer

Mathematics, Physics, and Computer Science Faculty Articles and Research

Assuming that quantum states, including pure states, represent subjective degrees of belief rather than objective properties of systems, the question of what other elements of the quantum formalism must also be taken as subjective is addressed. In particular, we ask this of the dynamical aspects of the formalism, such as Hamiltonians and unitary operators. Whilst some operations, such as the update maps corresponding to a complete projective measurement, must be subjective, the situation is not so clear in other cases. Here, it is argued that all trace preserving completely positive maps, including unitary operators, should be regarded as subjective, in …

Dynamical Control Of Qubit Coherence: Random Versus Deterministic Schemes, Lea F. Santos, Lorenza Viola

Dartmouth Scholarship

We reexamine the problem of switching off unwanted phase evolution and decoherence in a single two-state quantum system in the light of recent results on random dynamical decoupling methods [L. Viola and E. Knill, Phys. Rev. Lett. 94, 060502 (2005)]. A systematic comparison with standard cyclic decoupling is effected for a variety of dynamical regimes, including the case of both semiclassical and fully quantum decoherence models. In particular, exact analytical expressions are derived for randomized control of decoherence from a bosonic environment. We investigate quantitatively control protocols based on purely deterministic, purely random, as well as hybrid design, and …

Lattice Quantum Algorithm For The Schrodinger Wave Equation In 2+1 Dimensions With A Demonstration By Modeling Soliton Instabilities, Jeffrey Yepez, George Vahala, Linda L. Vahala

Electrical & Computer Engineering Faculty Publications

A lattice-based quantum algorithm is presented to model the non-linear Schrödinger-like equations in 2 + 1 dimensions. In this lattice-based model, using only 2 qubits per node, a sequence of unitary collide (qubit-qubit interaction) and stream (qubit translation) operators locally evolve a discrete field of probability amplitudes that in the long-wavelength limit accurately approximates a non-relativistic scalar wave function. The collision operator locally entangles pairs of qubits followed by a streaming operator that spreads the entanglement throughout the two dimensional lattice. The quantum algorithmic scheme employs a non-linear potential that is proportional to the moduli square of the wave function. …

Dynamics Of A Nanomechanical Resonator Coupled To A Superconducting Single-Electron Transistor, M. P. Blencowe, J. Imbers, A. D. Armour

Dartmouth Scholarship

We present an analysis of the dynamics of a nanomechanical resonator coupled to a superconducting single-electron transistor (SSET) in the vicinity of Josephson quasi-particle (JQP) and double Josephson quasi-particle (DJQP) resonances. For weak coupling and wide separation of dynamical timescales, we find that for either superconducting resonances the dynamics of the resonator are given by a Fokker–Planck equation, i.e. the SSET behaves effectively as an equilibrium heat bath, characterized by an effective temperature, which also damps the resonator and renormalizes its frequency. Depending on the gate and drain–source voltage bias points with respect to the superconducting resonance, the SSET can …

A Structure Theorem For Stationary Perfect Fluids, Brendan Guilfoyle

Preprints

It is proven that, under mild physical assumptions, an isolated stationary relativistic perfect fluid consists of a finite number of cells fibred by invariant annuli or invariant tori. For axially symmetric circular flows it is shown that the fluid consists of cells fibred by rigidly rotating annuli or tori.

Shape Invariance In Supersymmetric Quantum Mechanics And Its Application To Selected Special Functions Of Modern Physics, Chad Husko, Brenton Knuffman, Asim Gangopadhyaya, Jeffrey Mallow

Physics: Faculty Publications and Other Works

We applied the methods of supersymmetric quantum mechanics to differential equations that generate well-known special functions of modern physics. This application provides new insight into these functions and generates recursion relations among them. Some of these recursion relations are apparently new (or forgotten), as they are not available in commonly used texts and handbooks. This method can be easily extended to explore other special functions of modern physics.

Exactly Solvable Systems And The Quantum Hamilton Jacobi Formalism, C. Rasinariu, John J. Dykla, Asim Gangopadhyaya, Jeffrey Mallow

Physics: Faculty Publications and Other Works

We connect Quantum Hamilton-Jacobi Theory with supersymmetric quantum mechanics (SUSYQM). We show that the shape invariance, which is an integrability condition of SUSYQM, translates into fractional linear relations among the quantum momentum functions.

Intermediate Phase Of The One Dimensional Half-Filled Hubbard-Holstein Model, R. T. Clay, Rahul Hardikar

Scholarship and Professional Work - LAS

We present a numerical study of the Hubbard-Holstein model in one dimension at half filling, including finite-frequency quantum phonons. At half filling, the effects of the electron-phonon and electron-electron interactions compete with the Holstein phonon coupling acting as an effective negative Hubbard on-site interaction U that promotes on-site electron pairs and a Peierls charge-density wave state. Most previous work on this model has assumed that only Peierls or Mott phases are possible at half filling. However, there has been speculation that a third metallic phase exists between the Peierls and Mott phases. We confirm the intermediate phase, and show that …

Quantum Quasi-Paradoxes And Quantum Sorites Paradoxes, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

There can be generated many paradoxes or quasi-paradoxes that may occur from the combination of quantum and non-quantum worlds in physics. Even the passage from the micro-cosmos to the macro-cosmos, and reciprocally, can generate unsolved questions or counter-intuitive ideas. We define a quasi-paradox as a statement which has a prima facie self-contradictory support or an explicit contradiction, but which is not completely proven as a paradox. We present herein four elementary quantum quasi-paradoxes and their corresponding quantum Sorites paradoxes, which form a class of quantum quasi-paradoxes.

Exclusive Photoproduction Of The Cascade Ξ Hyperons, H. Bagdasaryan, M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, G. Gavalian, N. Guler, C. E. Hyde-Wright, A. V. Klimenko, S. E. Kuhn, L. M. Qin, L. B. Weinstein, J. Yun, Et Al., Clas Collaboration

Physics Faculty Publications

We report on the first measurement of exclusive Ξ^-(1321) hyperon photoproduction in 𝛾p → K⁺K⁺Ξ^- for 3.2 < E𝛾 < 3.9 GeV. The final state is identified by the missing mass in p(𝛾,K⁺K⁺)X measured with the CLAS detector at Jefferson Laboratory. We have detected a significant number of the ground state Ξ^-(1321)1/2⁺ and have estimated the total cross section for its production. We also have strong evidence for the first excited state Ξ^-(1530)3/2⁺. Photoproduction provides a copious source of Ξ's. We discuss the possibilities of a search for the recently proposed Ξ₅^- and Ξ₅^{+ …}

Global Analysis Of Data On The Proton Structure Function G₁ And The Extraction Of Its Moments, M. Osipenko, S. Simula, W. Melnitchouk, P. Bosted, V. Burkert, E. Christy, K. Griffioen, C. Keppel, S. Kuhn, G. Ricco

Physics Faculty Publications

Inspired by recent measurements with the CLAS detector at Jefferson Lab, we perform a self-consistent analysis of world data on the proton structure function g₁ in the range 0.17 < Q² < 30 (GeV/c)². We compute for the first time low-order moments of g, and study their evolution from small to large values of Q². The analysis includes the latest data on both the unpolarized inclusive cross sections and the ratio R = σ _L/σ_T from Jefferson Lab, as well as a new model for the transverse asymmetry A₂ in the resonance region. The contributions of …

Higher Twist Analysis Of The Proton G₁ Structure Function, M. Osipenko, W. Melnitchouk, S. Simula, P. Bosted, V. Burkert, M. E. Christy, K. Griffioen, C. Keppel, S. E. Kuhn

Physics Faculty Publications

We perform a global analysis of all available spin-dependent proton structure function data, covering a large range of Q², 1 ⩽ Q² ⩽ 30 GeV², and calculate the lowest moment of the g₁ structure function as a function of Q². From the Q² dependence of the lowest moment we extract matrix elements of twist-4 operators, and determine the color electric and magnetic polarizabilities of the proton to be X_E= 0.026 ± 0.015(stat) ± ^0.021_0.024 (sys) and X_B= -0.013 ∓ 0.007(stat) ∓ ^0.010 _0.012(sys), respectively.

High-Energy Effective Action From Scattering Of Qcd Shock Waves, Ian Balitsky

Physics Faculty Publications

At high energies, the relevant degrees of freedom are Wilson lines—infinite gauge links ordered along straight lines collinear to the velocities of colliding particles. The effective action for these Wilson lines is determined by the scattering of QCD shock waves. I develop the symmetric expansion of the effective action in powers of strength of one of the shock waves and calculate the leading term of the series. The corresponding first-order effective action, symmetric with respect to projectile and target, includes both up and down fan diagrams and pomeron loops.

Pre- And Post-Selection Paradoxes And Contextuality In Quantum Mechanics, Matthew S. Leifer, Robert W. Spekkens

Mathematics, Physics, and Computer Science Faculty Articles and Research

Many seemingly paradoxical effects are known in the predictions for outcomes of intermediate measurements made on pre- and post-selected quantum systems. Despite appearances, these effects do not demonstrate the impossibility of a noncontextual hidden variable theory, since an explanation in terms of measurement disturbance is possible. Nonetheless, we show that for every paradoxical effect wherein all the pre- and post-selected probabilities are 0 or 1 and the pre- and post-selected states are nonorthogonal, there is an associated proof of the impossibility of a noncontextual hidden variable theory. This proof is obtained by considering all the measurements involved in the paradoxical …

Bell's Jump Process In Discrete Time, Jonathan Barrett, Matthew S. Leifer, Roderich Tumulka

Mathematics, Physics, and Computer Science Faculty Articles and Research

The jump process introduced by J. S. Bell in 1986, for defining a quantum field theory without observers, presupposes that space is discrete whereas time is continuous. In this letter, our interest is to find an analogous process in discrete time. We argue that a genuine analog does not exist, but provide examples of processes in discrete time that could be used as a replacement.

Optimal Cooling Strategies For Magnetically Trapped Atomic Fermi-Bose Mixtures, Michael Brown-Hayes, Roberto Onofrio

Dartmouth Scholarship

We discuss cooling efficiency for different-species Fermi-Bose mixtures in magnetic traps. A better heat capacity matching between the two atomic species is achieved by a proper choice of the Bose cooler and the magnetically trappable hyperfine states of the mixture. When a partial spatial overlap between the two species is also taken into account, the deepest Fermi degeneracy is obtained for an optimal value of the trapping frequency ratio between the two species. This can be achieved by assisting the magnetic trap with a deconfining light beam, as shown in the case of fermionic 6Li mixed with 23Na, 87Rb, and …

From Guts To God: Credulity, Postmodernism, And Contemporary Physics, Michael Hardin

Reconstruction: Studies in Contemporary Culture

[Editors' Introduction]

In an attempt to remove one of the major misunderstandings made by individuals in the humanities about contemporary physics, the issue of incredulity, this essay examines Lyotard's The Postmodern Condition: A Report on Knowledge against contemporary and twentieth-century theories and discoveries in physics. One of the best arguments against incredulity is the frequent use of god as metaphor within physics. In Fashionable Nonsense: Postmodern Intellectuals' Abuse of Science, Alan Sokal and Jean Bricmont, two physicists, argue that the use of metaphor is one of the characteristics of postmodern science; this essay concludes with a discussion of those elements …

Casimir Force Between Eccentric Cylinders, D. A. R. Dalvit, F. C. Lombardo, F. D D. Mazzitelli, R Onofrio

Dartmouth Scholarship

We consider the Casimir interaction between a cylinder and a hollow cylinder, both conducting, with parallel axis and slightly different radii. The Casimir force, which vanishes in the coaxial situation, is evaluated for both small and large eccentricities using the proximity approximation. The cylindrical configuration offers various experimental advantages with respect to the parallel planes or the plane-sphere geometries, leading to favourable conditions for the search of extra-gravitational forces in the micrometer range and for the observation of finite-temperature corrections.

Hong-Ou-Mandel Cloning: Quantum Copying Without An Ancilla, Irfan Ali Khan, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this paper we report an experimental realization of an ancilla-free 1→2 phase-covariant quantum cloner. The cloner is realized by interfering a linearly polarized photon, which we wish to clone with a circularly polarized photon at a beam splitter. The two-photon effect can be understood in light of Hong-Ou-Mandel interference. The fidelity of the cloner was measured as 0.829±0.008 for the 0∕90 basis and 0.835±0.006 for the 45∕135 basis, which is in good agreement with the theoretical prediction of 5∕6 fidelity. The experimental scheme is straightforward and has a high cloning success rate.

The Quantum And The Cosmos, Edward (Rocky) W. Kolb, Joseph D. Lykken

IMSA Great Minds Program ®

Fermilab physicists, Dr. Rocky Kolb and Dr. Joe Lykken team up to explain the connection of the physics of the very small to the physics of the cosmos and their discovery of a fundamental contradiction regarding how these mysteries have led to the development of new ideas: string theory, inflation, extra dimensions and Wimpzillas, as well as Higgs boson, and other mysteries that cosmologists care about, like dark energy.

Dr. Rocky Kolb is the founding head of the NASA/Fermilab Astrophysics Group at Fermi National Accelerator Laboratory. He is also a Professor of Astronomy and Astrophysics at The University of Chicago. …

Quantum And Classical Coincidence Imaging, Ryan S. Bennink, Sean J. Bentley, Robert W. Boyd, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

Coincidence, or ghost, imaging is a technique that uses two correlated optical fields to form an image of an object. In this work we identify aspects of coincidence imaging which can be performed with classically correlated light sources and aspects which require quantum entanglement. We find that entangled photons allow high-contrast, high-resolution imaging to be performed at any distance from the light source. We demonstrate this fact by forming ghost images in the near and far fields of an entangled photon source, noting that the product of the resolutions of these images is a factor of 3 better than that …

Logical Pre- And Post-Selection Paradoxes, Measurement-Disturbance And Contextuality, Matthew S. Leifer, R. W. Spekkens

Mathematics, Physics, and Computer Science Faculty Articles and Research

Many seemingly paradoxical effects are known in the predictions for outcomes of measurements made on pre- and post-selected quantum systems. A class of such effects, which we call “logical pre- and post-selection paradoxes”, bear a striking resemblance to proofs of the Bell-Kochen-Specker theorem, which suggests that they demonstrate the contextuality of quantum mechanics. Despite the apparent similarity, we show that such effects can occur in noncontextual hidden variable theories, provided measurements are allowed to disturb the values of the hidden variables.

Complete Angular Distribution Measurements Of Two-Body Deuteron Photodisintegration Between 0.5 And 3 Gev, H. Bagdasaryan, H. Bektasoglu, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, A. Klein, A. V. Klimenko, S. E. Kuhn, F. Sabatié, S. Stepanyan, L. B. Weinstein, J. Yun, Et Al., The Clas Collaboration

Physics Faculty Publications

Nearly complete angular distributions of the two-body deuteron photodisintegration differential cross section have been measured using the CEBAF Large Acceptance Spectrometer detector and the tagged photon beam at the Thomas Jefferson National Accelerator Facility. The data cover photon energies between 0.5 and 3.0 GeV and center-of-mass proton scattering angles 10°–160°. The data show a persistent forward-backward angle asymmetry over the explored energy range, and are well described by the nonperturbative quark gluon string model.

Complete Measurement Of Three-Body Photodisintegration Of 3He For Photon Energies Between 0.35 And 1.55 Gev, H. Bagdasaryan, M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, G. Gavalian, N. Guler, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, L. M. Qin, S. Stepanyan, L. B. Weinstein, J. Yun, Et Al., The Clas Collaboration

Physics Faculty Publications

The three-body photodisintegration of ³He has been measured with the CLAS detector at Jefferson Lab, using tagged photons of energies between 0.35 GeV and 1.55 GeV. The large acceptance of the spectrometer allowed us for the first time to cover a wide momentum and angular range for the two outgoing protons. Three kinematic regions dominated by either two- or three-body contributions have been distinguished and analyzed. The measured cross sections have been compared with results of a theoretical model, which, in certain kinematic ranges, have been found to be in reasonable agreement with the data.

Experimental Determination Of The Evolution Of The Bjorken Integral At Low Q², A. Deur, P. Bosted, V. Burkert, G. Cates, J.P. Chen, Seonho Choi, D. Crabb, C.W. De Jager, R. De Vita, G.E. Dodge, R. Fatemi, T.A. Forest, F. Garibaldi, R. Gilman, E. W. Hughes, X. Jiang, W. Korsch, S. E. Kuhn, W. Melnitchouk, Z.-E. Meziani, R. Minehart, A.V. Skabelin, K. Slifer, M. Taiuti, J. Yun

Physics Faculty Publications

We extract the Bjorken integral 𝚪₁^p-n in the range 0.17 < Q² <1.10 GeV² from inclusive scattering of polarized electrons by polarized protons, deuterons, and ³He, for the region in which the integral is dominated by nucleon resonances. These data bridge the domains of the hadronic and partonic descriptions of the nucleon. In combination with earlier measurements at higher Q², we extract the nonsinglet twist-4 matrix element f₂.

Hyperon Photoproduction In The Nucleon Resonance Region, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, S. E. Kuhn, L. M. Qin, L. B. Weinstein, J. Yun, Et Al., Clas Collaboration

Physics Faculty Publications

High-statistics cross sections and recoil polarizations for the reactions γ+p → K⁺+ Λ and γ+p→K⁺+ Σ⁰ have been measured at CLAS for center-of-mass energies between 1.6 and 2.3 GeV. In the K+Λ channel we confirm a resonance-like structure near W = 1.9 GeV at backward kaon angles. Our data show more complex s- and u- channel behavior than previously seen, since structure is also present at forward angles, but not at central angles. The position and width change with angle, indicating that more than one resonance is playing a role. Large positive Λ polarization at …

Measurement Of Beam-Spin Asymmetries For Π⁺ Electroproduction Above The Baryon Resonance Region, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, S. E. Kuhn, L. M. Qin, F. Sabatié, L. B. Weinstein, J. Yun, Et Al., Clas Collaboration

Physics Faculty Publications

We report the first evidence for a nonzero beam-spin azimuthal asymmetry in the electroproduction of positive pions in the deep-inelastic kinematic region. Data for the reaction e^→pe'π⁺X have been obtained using a polarized electron beam of 4.3 GeV with the CEBAF Large Acceptance Spectrometer at the Thomas Jefferson National Accelerator Facility. The amplitude of the sin ᵠ modulation increases with the momentum of the pion relative to the virtual photon, z. In the range z = 0.5-0.8 the average amplitude is 0.038 ± 0.005 ± 0.003 for a missing mass M_x > 1.1 GeV and 0.037 …