Low-energy effective theory of the toric code model in a parallel magnetic field

A new field emission scanning transmission electron microscope has been constructed for the NSF HREM facility at Arizona State University. The microscope is to be used for studies of surfaces, and incorporates several surface-related features, including provision for analysis of secondary and Auger electrons; these electrons are collected through the objective lens from either side of the sample, using the parallelizing action of the magnetic field. This collimates all the low energy electrons, which spiral in the high magnetic field. Given an initial field Bi∼1T, and a final (parallelizing) field Bf∼0.01T, all electrons emerge into a cone of semi-angle θf≤6°. The main practical problem in the way of using this well collimated beam of low energy (0-2keV) electrons is that it is travelling along the path of the (100keV) probing electron beam. To collect and analyze them, they must be deflected off the beam path with minimal effect on the probe position.

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STABLE hc/e VORTICES IN SUPERCONDUCTORS WITH SPIN-CHARGE SEPARATION

International Journal of Modern Physics B ◽

10.1142/s0217979292000293 ◽

1992 ◽

Vol 06 (05n06) ◽

pp. 509-526

Author(s):

Subir Sachdev

Keyword(s):

Magnetic Field ◽

Magnetic Flux ◽

Normal State ◽

Phenomenological Model ◽

Charge Separation ◽

Cuprate Superconductors ◽

Superconducting Phase ◽

Low Energy ◽

Large N ◽

Normal State Properties

A phenomenological model, F, of the superconducting phase of systems with spin-charge separation and antiferromagnetically induced pairing is studied. Above Hc1, magnetic flux can always pierce the superconductor in vortices with flux hc/2e, but regimes are found in which vortices with flux hc/e are preferred. Little-Park and other experiments, which examine periodicities with a varying magnetic field, always observe a period of hc/2e. The low energy properties of a symplectic large-N expansion of a model of the cuprate superconductors are argued to be well described by F. This analysis and some normal state properties of the cuprates suggest that hc/e vortices should be stable at the lowest dopings away from the insulating state at which superconductivity first occurs.

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The low-energy effective theory of axions and ALPs

Journal of High Energy Physics ◽

10.1007/jhep04(2021)063 ◽

2021 ◽

Vol 2021 (4) ◽

Author(s):

Martin Bauer ◽

Matthias Neubert ◽

Sophie Renner ◽

Marvin Schnubel ◽

Andrea Thamm

Keyword(s):

High Energy ◽

New Physics ◽

Mass Scale ◽

Low Energy ◽

Effective Theory ◽

Loop Order ◽

Flavor Changing ◽

Effective Lagrangian ◽

Anomalous Dimensions ◽

Pseudoscalar Mesons

Abstract Axions and axion-like particles (ALPs) are well-motivated low-energy relics of high-energy extensions of the Standard Model, which interact with the known particles through higher-dimensional operators suppressed by the mass scale Λ of the new-physics sector. Starting from the most general dimension-5 interactions, we discuss in detail the evolution of the ALP couplings from the new-physics scale to energies at and below the scale of electroweak symmetry breaking. We derive the relevant anomalous dimensions at two-loop order in gauge couplings and one-loop order in Yukawa interactions, carefully considering the treatment of a redundant operator involving an ALP coupling to the Higgs current. We account for one-loop (and partially two-loop) matching contributions at the weak scale, including in particular flavor-changing effects. The relations between different equivalent forms of the effective Lagrangian are discussed in detail. We also construct the effective chiral Lagrangian for an ALP interacting with photons and light pseudoscalar mesons, pointing out important differences with the corresponding Lagrangian for the QCD axion.

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The effect of magnetic field on the dynamics of gas bubbles in water electrolysis

Scientific Reports ◽

10.1038/s41598-021-87947-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yan-Hom Li ◽

Yen-Ju Chen

Keyword(s):

Magnetic Field ◽

Swirling Flow ◽

Gas Bubbles ◽

Water Electrolysis ◽

Platinum Electrodes ◽

Optimal Layout ◽

Parallel Magnetic Field ◽

Hydrogen Bubbles ◽

The Magnetic Field ◽

Sluggish Flow

AbstractThis study determines the effect of the configuration of the magnetic field on the movement of gas bubbles that evolve from platinum electrodes. Oxygen and hydrogen bubbles respectively evolve from the surface of the anode and cathode and behave differently in the presence of a magnetic field due to their paramagnetic and diamagnetic characteristics. A magnetic field perpendicular to the surface of the horizontal electrode causes the bubbles to revolve. Oxygen and hydrogen bubbles revolve in opposite directions to create a swirling flow and spread the bubbles between the electrodes, which increases conductivity and the effectiveness of electrolysis. For vertical electrodes under the influence of a parallel magnetic field, a horizontal Lorentz force effectively detaches the bubbles and increases the conductivity and the effectiveness of electrolysis. However, if the layout of the electrodes and magnetic field results in upward or downward Lorentz forces that counter the buoyancy force, a sluggish flow in the duct inhibits the movement of the bubbles and decreases the conductivity and the charging performance. The results in this study determine the optimal layout for an electrode and a magnetic field to increase the conductivity and the effectiveness of water electrolysis, which is applicable to various fields including energy conversion, biotechnology, and magnetohydrodynamic thruster used in seawater.

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Flavour Anomalies in a U(1) SUSY Extension of the SM

Symmetry ◽

10.3390/sym13020191 ◽

2021 ◽

Vol 13 (2) ◽

pp. 191

Author(s):

Alexander Bednyakov ◽

Alfiia Mukhaeva

Keyword(s):

Standard Model ◽

Parameter Space ◽

Gauge Boson ◽

New Physics ◽

Low Energy ◽

Effective Theory ◽

The Standard Model ◽

Meson Mixing ◽

Additional Anomaly ◽

Lepton Flavour

Flavour anomalies have attracted a lot of attention over recent years as they provide unique hints for possible New Physics. Here, we consider a supersymmetric (SUSY) extension of the Standard Model (SM) with an additional anomaly-free gauge U(1) group. The key feature of our model is the particular choice of non-universal charges to the gauge boson Z′, which not only allows a relaxation of the flavour discrepancies but, contrary to previous studies, can reproduce the SM mixing matrices both in the quark and lepton sectors. We pay special attention to the latter and explicitly enumerate all parameters relevant for our calculation in the low-energy effective theory. We find regions in the parameter space that satisfy experimental constraints on meson mixing and LHC Z′ searches and can alleviate the flavour anomalies. In addition, we also discuss the predictions for lepton-flavour violating decays B+→K+μτ and B+→K+eτ.

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