Physics Commons^™

Kl−Ks Mass Difference And Supersymmetric Left-Right-Symmetric Theories, Asim Gangopadhyaya

Asim Gangopadhyaya

The supersymmetric contributions to the K_L−K_S mass difference makes the previously obtained bounds on the right-handed scale (M_R>1.6 TeV) much weaker. This raises the interesting possibility that the left-right model could be tested as an alternative to SU_L(2)⊗U(1) at low energies. Also we find that to demand that the supersymmetric contribution to the K_L−K_S mass difference be less than 3.5×10⁻¹⁵ GeV requires that scalar-quark masses be more than 400 GeV.

New Exactly Solvable Hamiltonians - Shape Invariance And Self-Similarity, David Barclay, Ranabir Dutt, Asim Gangopadhyaya, Avinash Khare, A. Pagnamenta, Uday Sukhatne

Asim Gangopadhyaya

We discuss in some detail the self-similar potentials of Shabat and Spiridonov which are reflectionless and have an infinite number of bound states. We demonstrate that these self-similar potentials are in fact shape invariant potentials within the formalism of supersymmetric quantum mechanics. In particular, using a scaling ansatz for the change of parameters, we obtain a large class of new, reflectionless, shape invariant potentials of which the Shabat-Spiridonov ones are a special case. These new potentials can be viewed as q-deformations of the single soliton solution corresponding to the Rosen-Morse potential. Explicit expressions for the energy eigenvalues, eigenfunctions and transmission …

Noncentral Potentials And Spherical Harmonics Using Supersymmetry And Shape Invariance, Ranabir Dutt, Asim Gangopadhyaya, Uday Sukhatne

Asim Gangopadhyaya

It is shown that the operator methods of supersymmetric quantum mechanics and the concept of shape invariance can profitably be used to derive properties of spherical harmonics in a simple way. The same operator techniques can also be applied to several problems with noncentral vector and scalar potentials. As examples, we analyze the bound state spectra of an electron in a Coulomb plus an Aharonov – Bohm field and/or in the magnetic field of a Dirac monopole.

Supersymmetric Quantum Mechanics And Solvable Models, Asim Gangopadhyaya, Jonathan Bougie, Jeffrey Mallow, C. Rasinariu

Asim Gangopadhyaya

We review solvable models within the framework of supersymmetric quantum mechanics (SUSYQM). In SUSYQM, the shape invariance condition insures solvability of quantum mechanical problems. We review shape invariance and its connection to a consequent potential algebra. The additive shape invariance condition is specified by a difference-differential equation; we show that this equation is equivalent to an infinite set of partial differential equations. Solving these equations, we show that the known list of h-independent superpotentials is complete. We then describe how these equations could be extended to include superpotentials that do depend on h.

Comment On "Ideal Capacitor Circuits And Energy Conservation" By K. Mita And M. Boufaida [Am. J. Phys. 67 (8), 737-739 (1999)], Asim Gangopadhyaya, Jeffrey Mallow

Asim Gangopadhyaya

No abstract provided.

Renormalization Group Equations In Broken Supersymmetric Theories Using Superspace Methods, Asim Gangopadhyaya, Darwin Chang

Asim Gangopadhyaya

We apply the superfield method with the spurion technique to derive the renormalization-group equations in broken supersymmetric theories. We point out some possible ambiguities in this procedure and show that it is in general necessary to express the supersymmetry-breaking terms in explicit D-type form. We also found that it is possible to construct broken supersymmetric theories where some of the symmetry-breaking parameters do not receive any infinite renormalization.

Coordinate Realizations Of Deformed Lie Algebras With Three Generator, Ranabir Dutt, Asim Gangopadhyaya, C. Rasinariu, Uday Sukhatne

Asim Gangopadhyaya

Differential realizations in coordinate space for deformed Lie algebras with three generators are obtained using bosonic creation and annihilation operators satisfying Heisenberg commutation relations. The unified treatment presented here contains as special cases all previously given coordinate realizations of so(2,1), so(3), and their deformations. Applications to physical problems involving eigenvalue determination in nonrelativistic quantum mechanics are discussed.

Anyonic Superconductivity In A Modified Large-U Hubbard Model, Asim Gangopadhyaya, Prasanta Panigrahi

Asim Gangopadhyaya

A modified large-U Hubbard model at half filling is analyzed by a mean-field approach. Preserving a local U(1) symmetry of the action, the fluctuations about half filling are studied in the spirit of the commensurate-flux-phase condition. The fluctuations then contribute a Chern-Simons term to the tree-level Lagrangian with a coefficient appropriate to that of a half fermion. With the Coulomb repulsion term, we study the low-energy excitations of the model and show the existence of superconductivity in the presence of a four-Fermi interaction term.

Superspace Ward Identities In Supersymmetric Gauge Theories, Asim Gangopadhyaya, Darwin Chang

Asim Gangopadhyaya

In superspace formulation of supersymmetric gauge theories, gauge invariance requires an infinite set of identities between the infinite set of renormalization constants. Using Ward identities in superspace, the same is derived. These identities at one loop level are also demonstrated.

Heterotic Conformal Field Theory And Gepner’S Construction, Darwin Chang, Asim Gangopadhyaya, Alok Kumar, Jin Wang

Asim Gangopadhyaya

We discuss some general properties of heterotic conformal field theory in which conformal anomalies c are different for the left-moving and right-moving sectors. It is precisely this type of theory that can be applied immediately to the construction of heterotic string theory. We discuss a general way of constructing such a theory using free fermions. The construction is then applied to generalize Gepner's construction of superstring solutions using the tensor products of N=2 superconformal field theories.

Economics Of Nuclear Power And Climate Change Mitigation Policies, Nico Bauer, Robert Brecha, Gunnar Luderer

Robert J. Brecha

The events of March 2011 at the nuclear power complex in Fukushima, Japan, raised questions about the safe operation of nuclear power plants, with early retirement of existing nuclear power plants being debated in the policy arena and considered by regulators. Also, the future of building new nuclear power plants is highly uncertain. Should nuclear power policies become more restrictive, one potential option for climate change mitigation will be less available. However, a systematic analysis of nuclear power policies, including early retirement, has been missing in the climate change mitigation literature. We apply an energy economy model framework to derive …

The Sign Learning Kink (Silk) Based Quantum Monte Carlo (Qmc), Xiaoyao Ma, Frank Loffler, Randall W. Hall, Karol Kowalski, Mark Jarrell, Juana Moreno

Randall W. Hall

Composite Fermions And Integer Partitions, Arthur Benjamin, Jennifer Quinn, John Quinn, Arkadiusz Wojs

Jennifer J. Quinn

We utilize the KOH theorem to prove the unimodality of integer partitions with at most a parts, all parts less than or equal to b, that are required to contain either repeated or consecutive parts. We connect this result to an open question in quantum physics relating the number of distinct total angular momentum multiplets of a system of N fermions, each with angular momentum ℓ, to those of a system in which each Fermion has angular momentum ℓ*=ℓ−N+1.

The Fermion–Boson Transformation In Fractional Quantum Hall Systems, John Quinn, Arkadiusz Wojs, Jennifer Quinn, Arthur Benjamin

Jennifer J. Quinn

A Fermion to Boson transformation is accomplished by attaching to each Fermion a single flux quantum oriented opposite to the applied magnetic field. When the mean field approximation is made in the Haldane spherical geometry, the Fermion angular momentum l_F is replaced by l_B - l_F - 1/2(N-1). The set of allowed total angular momentum multiplets is identical in the two different pictures. The Fermion and Boson energy spectra in the presence of many body interactions are identical if and only if the pseudopotential is "harmonic" in form. However, similar low energy bands of states with Laughlin correlations occur in …

Constraint-Preserving Sommerfeld Conditions For The Harmonic Einstein Equations, Maria Babiuc-Hamilton, H-O. Kreiss, Jeffrey Winicour

Maria Babiuc-Hamilton

The principle part of Einstein equations in the harmonic gauge consists of a constrained system of 10 curved space wave equations for the components of the space-time metric. A new formulation of constraint-preserving boundary conditions of the Sommerfeld-type for such systems has recently been proposed. We implement these boundary conditions in a nonlinear 3D evolution code and test their accuracy.

Proofs Of The Kochen-Specker Theorem Based On The N-Qubit Pauli Group, Padmanabhan Aravind, Mordecai Waegell

Padmanabhan K. Aravind

We present a number of observables-based proofs of the KochenSpecker (KS) theorem based on the N-qubit Pauli group for N ≥ 4, thus adding to the proofs that have been presented earlier for the 2- and 3-qubit groups. These proofs have the attractive feature that they can be presented in the form of diagrams from which they are obvious by inspection. They are also irreducible in the sense that they cannot be reduced to smaller proofs by ignoring some subset of qubits and/or observables in them. A simple algorithm is given for transforming any observables-based KS proof into a large …

Optical Switching With Cold Atoms, Andrew Dawes

Andrew M C Dawes

A Viewpoint on: Efficient All-Optical Switching Using Slow Light within a Hollow Fiber M. Bajcsy, S. Hofferberth, V. Balic, T. Peyronel, M. Hafezi, A. S. Zibrov, V. Vuletic, and M. D. Lukin Phys. Rev. Lett. 102, 203902 (2009) – Published May 18, 2009

Incommensurate Spin Fluctuations In High-Transition Temperature Superconductors, Barrett Wells, Young Lee, Marc Kastner, Rebecca Christianson, Robert Birgeneau, Kazuyoshi Yamada, Yasuo Endoh, Gen Shirane

Rebecca J. Christianson

Neutron scattering experiments have revealed a fascinating interplay between the hole doping, the spin fluctuations, and the superconductivity of the cuprate superconductors. Recently, electrochemical techniques have been used to produce large single crystals of La2CuO4+ y, which has mobile oxygen dopants. Staging behavior of the excess oxygen has been demonstrated, and the low-energy spin fluctuations in stage 6 La2CuO4+ y have been measured. The spin fluctuations are incommensurate with the lattice and have spatial, energy, and temperature dependencies very much like those in La2− xSrxCuO4, with similar high transition temperature. This establishes the universality of the incommensurate spin fluctuations among …

Structures And Incommensurate Spin Excitations In Excess Oxygen-Doped La2cuo4+Y, Robert Birgeneau, Rebecca Christianson, Yasuo Endoh, Marc Kastner, Young Lee, Gen Shirane, Barrett Wells, Kazuyoshi Yamada

Rebecca J. Christianson

Over the past decade, we have studied in detail the low-energy spin fluctuations in :a2−xSrxCuO4 for xbetween 0 and 0.18. Our experiments, as well as those by others, have revealed a fascinating interplay between the hole doping, the static and dynamic spin fluctuations and superconductivity. Recently, using electrochemical techniques, we have learned how to produce large single crystals of La2CuO4+y which are relatively homogenous. In this latter system, the dopants are characterized by annealed rather than quenched disorder. Furthermore, we have demonstrated staging behavior of the excess oxygen analogous to staging in intercalated graphite. We have now succeeded in carrying …

Polarimetry Studies For The Npdgamma Experiment At The Sns, Jonny Dadras

Jonny Dadras

The NPDGamma collaboration aims to measure a parity-violating directional gamma-ray asymmetry from the capture of polarized cold neutrons on protons. The asymmetry, predicted to be on the order of 50 ppb, is a result of the weak interaction between mesons and nucleons during the neutron capture reaction. The experiment is designed to make a statistics limited measurement of the asymmetry at the level of about 20%. The experiment will be carried out at the Fundamental neutron Physics Beamline (FnPB) at the Spallation Neutron Source (SNS). The neutron beam is polarized by a super-mirror polarizer. A 9.5 G magnetic field guides …

Decoherence As A Measure Of Entanglement, Padmanabhan Aravind, Denis Tolkunov, Vladimir Privman

Padmanabhan K. Aravind

For a solvable pure-decoherence model, we confirm by an explicit model calculation that the decay of entanglement of two state systems (two quibits) is approximately governed by the product of the suppression factors describing decoherence of the subsystems, provided that they are subject to uncorrelated sources of quantum noise. This demonstrates an important physical property that separated open quantum systems can evolve quantum mechanically on time scales larger than the times for which they remain entangled.

Quantum Mysteries Revisited Again, Padmanabhan Aravind

Padmanabhan K. Aravind

This paper describes a device, consisting of a central source and two widely separated detectors with six switch settings each, that provides a simple gedanken demonstration of the non-classical correlations that are the subject of Bell’s theorem without relying on either statistical effects or the occurrence of rare events. The mechanism underlying the operation of the device is revealed for readers with a knowledge of quantum mechanics.

The Penrose Dodecahedron Revisited, Padmanabhan Aravind, Jordan Massad

Padmanabhan K. Aravind

This paper gives an elementary account of the ‘‘Penrose dodecahedron,’’ a set of 40 states of a spin- 3 2 particle used by Zimba and Penrose @Stud. Hist. Phil. Sci. 24, 697–720 ~1993!# to give a proof of Bell’s nonlocality theorem. The Penrose rays are constructed here from the rotation operator of a spin- 3 2 particle and the geometry of a dodecahedron, and their orthogonality properties are derived and illustrated from a couple of different viewpoints. After recalling how the proof of Bell’s theorem can be reduced to a coloring problem on the Penrose rays, a ‘‘proof-tree’’ argument is …

Quark-Antiquark Condensates In Strong Magnetic Fields, Alec Schramm, Berndt Muller, Stefan Schramm

Alec J Schramm

We discuss the effect of large external magnetic fields on the QCD vacuum structure. We show that the deformed vacuum leads to substantial changes in the hadronic spectrum.

W Boson Condensation In P-P Collisions?, Alec Schramm, Stefan Schramm, Berndt Muller

Alec J Schramm

We address the question of whether W+/- boson condensation can occur in high-energy collisions.

The (First) Three B’S Of The Skyrme Model, Alec Schramm

Alec J Schramm

No abstract provided.

Higgs Boson Production In Peripheral Heavy-Ion Collisions: Coherent Double-Pomeron Exchange, Alec Schramm, Berndt Muller

Alec J Schramm

Higgs boson production by coherent double-pomeron exchange in peripheral nuclear collisions at energies of several TeV per nucleon is calculated. It is shown that a trigger on quasi-elastic nuclear collisions strongly suppresses the cross section. The analogous two-photon process is predicted to dominate for collisions of heavy nuclei.

A Calculation Of The Deuteron As A Biskyrmion, Alec Schramm, Yossef Dothan, L. Beidenharn

Alec J Schramm

No abstract provided.