Particles In Strong Magnetic Field Research Articles

Creating anomalous Floquet Chern insulators with magnetic quantum walks

Charged particles in a two-dimensional lattice behave like a Chern topological insulator when subject to a perpendicular magnetic field. Here, the authors propose a realistic scheme to use neutral atoms in optical lattices to simulate the effect of the magnetic field and to study transport in the strong field regime, which is not accessible when working with conventional materials. Importantly, the topological behavior of these so-called magnetic quantum walks extends even beyond the Chern insulator model because they are periodically driven in time,. Magnetic quantum walks may open a new route to studying topological properties of charged particles in strong magnetic fields.

Development of a picosecond MCP based particle detector

Abstract A time-of-flight detector based on microchannel plates (MCP) is under development. The main goal is the creation of a radiation hard large area detector providing ∼ 10 ps time resolution for single charged particle in strong magnetic field. Conceptually, the detector consists of Cherenkov radiator covered with semitransparent photocathode followed by a chevron pair of MCPs. The detector design and the status of the development are reported.

Incompressibility Estimates for the Laughlin Phase, Part II

We consider fractional quantum Hall states built on Laughlin’s original N-body wave-functions, i.e., they are of the form holomorphic × Gaussian and vanish when two particles come close, with a given polynomial rate. Such states appear naturally when looking for the ground state of 2D particles in strong magnetic fields, interacting via repulsive forces and subject to an external potential due to trapping and/or disorder. We prove that all functions in this class satisfy a universal local density upper bound, in a suitable weak sense. Such bounds are useful to investigate the response of fractional quantum Hall phases to variations of the external potential. Contrary to our previous results for a restricted class of wave-functions, the bound we obtain here is not optimal, but it does not require any additional assumptions on the wave-function, besides analyticity and symmetry of the pre-factor modifying the Laughlin function.

Realizing the Harper Hamiltonian with Laser-Assisted Tunneling in Optical Lattices

We experimentally implement the Harper Hamiltonian for neutral particles in optical lattices using laser-assisted tunneling and a potential energy gradient provided by gravity or magnetic field gradients. This Hamiltonian describes the motion of charged particles in strong magnetic fields. Laser-assisted tunneling processes are characterized by studying the expansion of the atoms in the lattice. The band structure of this Hamiltonian should display Hofstadter's butterfly. For fermions, this scheme should realize the quantum Hall effect and chiral edge states.

Three-dimensional elemental imaging by means of synchrotron radiation micro-XRF: developments and applications in environmental chemistry

The most brilliant sources of hard X-rays available for scientists today are provided by synchrotron radiation (SR) sources within electron or positron storage rings. These storage rings, or particle accelerators, were originally built for high-energy particle physics experiments, and the emission of synchrotron radiation, generated by the acceleration of relativistic charged particles in strong magnetic fields, was considered as an undesirable sideeffect. The unique characteristics of SR (extremely high brightness/intensity, natural collimation, polarization, energy tunability, and pulsed time structure), however, were quickly recognized to be very attractive for a large number of scientific disciplines, including X-ray spectroscopic applications with unsurpassed sensitivity and spatial resolution. The original use of synchrotron radiation in the socalled parasitic mode in the case of first-generation synchrotrons, initiated a rapid evolution towards secondand third-generation SR sources which have been optimized specifically for the production of synchrotron radiation of exceptional brilliance. Owing to the rapid development of synchrotron sources, associated microfocusing optical elements and the increasing availability of sophisticated X-ray detectors, scanning micro X-ray fluorescence (micro-XRF) techniques have become extremely powerful tools for twoand three-dimensional (2D/3D), non-destructive elemental analysis with exceptional sensitivity. A variety of scanning XRF techniques are currently available, such as conventional or dynamic microXRF scanning (2D), micro-XRF computed tomography (2D/ 3D), and confocal micro-XRF (2D/3D) [1]. When using synchrotron sources to produce the exciting microbeam, taking advantage of the high intensity, potential monochromaticity/tunability, and high degree of linear polarisation in the storage ring plane, these techniques offer the possibility to obtain quantitative information on the elemental distributions within the sample volume with trace level detection limits and on a (sub-)microscopic scale [2, 3]. X-ray microprobes installed at the most advanced third-generation SR sources, such as the European Synchrotron Radiation Facility (ESRF) in Grenoble, offer absolute detection limits (DLs) below 10 ag for the most efficiently excited transition elements with a potential lateral resolution level better than 50 nm [4, 5]. An exciting direction in the development of nondestructive elemental imaging methods is represented by the combination of synchrotron-based scanning microAnal Bioanal Chem (2008) 390:267–271 DOI 10.1007/s00216-007-1694-0

Spectra of radiation for spinless and spin relativistic particles in strong magnetic fields

Synchro-curvature radiation put forward by Zhang and Cheng is a new and universal radiation mechanism, it describes in detail the radiation properties of a relativistic charged particle moving in a curved magnetic field. This new radiation generalizes all the classical results of ordinary synchrotron and curvature radiations and reveals inherent linkage and unification between them. Additionly, a general, simple and unitary formula is provided for discussing the radiation problem in research of pulsars. However, the magnitude of the magnetic field of a pulsar is so strong (107-109T) that the quantum effects cannot be neglected. The GFWW method developed recently by Lieu and Axford is applied to generalize the results of Zhang and Cheng. The quantum limited synchro-curvature radiation spectra for spinless K-G particles and spin-1/2 Dirac particles are presented, respectively. Their radiation properties are also discussed.

2D dipole system in a strong field

Parallel dipoles in plane were simulated by Monte Carlo method. The suspension of magnetic (or superconductive) particles in strong magnetic field, for example, may be the physical realisation of the system. Solidification of the last is accompanied by anisotropic ordering of clusters strongly stretched along external field.

Phase anholonomy in the classical adiabatic motion of charged particles.

The classical adiabatic motion of charged particles in strong magnetic fields, otherwise known as guiding center motion, exhibits an anholonomic phase similar to Berry's phase and the phase discovered in a general context by Hannay. Analysis of this effect reveals that there often is no best way to define the gyrophase when magnetic field lines are curved. Instead, a change in the definition of the phase is a kind of gauge transformation, the study of which leads to new insight into guiding center theory. The path-dependent phase that occurs in this problem is coupled with the metrical structure of physical space, giving rise to a transport process for vectors and frames which is similar to parallel transport in non-Euclidean geometry. Strong analogies with Fermi-Walker transport and Thomas precession in special relativity are pointed out.

High-accuracy drift chambers and their use in strong magnetic fields

A method is proposed that allows the construction of drift multiwire proportional chambers with adjustable electric field suitable for the detection of high-energy charged particles in strong magnetic fields. Typical measured accuracies go from 50 to 200 μm, varying with the drift length, at 16 kG. The simple mechanical construction allows the wire distance to be adapted to the expected counting rate, even in the same chamber. Furthermore, the advantages of a current division method to obtain both orthogonal coordinates from the same wire are discussed.