2,464 research outputs found
Resistively detected nuclear magnetic resonance via a single InSb two-dimensional electron gas at high temperature
We report on the demonstration of the resistively detected nuclear magnetic
resonance (RDNMR) of a single InSb two-dimensional electron gas (2DEG) at
elevated temperatures up to 4 K. The RDNMR signal of 115In in the simplest
pseudospin quantum Hall ferromagnet triggered by a large direct current shows a
peak-dip line shape, where the nuclear relaxation time T1 at the peak and the
dip is different but almost temperature independent. The large Zeeman,
cyclotron, and exchange energy scales of the InSb 2DEG contribute to the
persistence of the RDNMR signal at high temperatures.Comment: 11pages,3figure
Resistively-detected NMR lineshapes in a quasi-one dimensional electron system
We observe variation in the resistively-detected nuclear magnetic resonance
(RDNMR) lineshapes in quantum Hall breakdown. The breakdown is locally occurred
in a gate-defined quantum point contact (QPC) region. Of particular interest is
the observation of a dispersive lineshape occured when the bulk 2D electron gas
(2DEG) is set to and the QPC filling factor to the vicinity
of , strikingly resemble the dispersive lineshape observed
on a 2D quantum Hall state. This previously unobserved lineshape in a QPC
points to simultaneous occurrence of two hyperfine-mediated spin flip-flop
processes within the QPC. Those events give rise to two different sets of
nuclei polarized in the opposite direction and positioned at a separate region
with different degree of electronic polarizations.Comment: Accepted as a rapid communication in PR
Decomposition of meron configuration of SU(2) gauge field
For the meron configuration of the SU(2) gauge field in the four dimensional
Minkowskii spacetime, the decomposition into an isovector field \bn,
isoscalar fields and , and a U(1) gauge field is
attained by solving the consistency condition for \bn. The resulting \bn
turns out to possess two singular points, behave like a monopole-antimonopole
pair and reduce to the conventional hedgehog in a special case. The
field also possesses singular points, while and are regular
everywhere.Comment: 18 pages, 5 figures, Sec.4 rewritten. 5 refs. adde
On Foundation of the Generalized Nambu Mechanics
We outline the basic principles of canonical formalism for the Nambu
mechanics---a generalization of Hamiltonian mechanics proposed by Yoichiro
Nambu in 1973. It is based on the notion of Nambu bracket which generalizes the
Poisson bracket to the multiple operation of higher order on
classical observables and is described by Hambu-Hamilton equations of motion
given by Hamiltonians. We introduce the fundamental identity for the
Nambu bracket which replaces Jacobi identity as a consistency condition for the
dynamics. We show that Nambu structure of given order defines a family of
subordinated structures of lower order, including the Poisson structure,
satisfying certain matching conditions. We introduce analogs of action from and
principle of the least action for the Nambu mechanics and show how dynamics of
loops (-dimensional objects) naturally appears in this formalism. We
discuss several approaches to the quantization problem and present explicit
representation of Nambu-Heisenberg commutation relation for case. We
emphasize the role higher order algebraic operations and mathematical
structures related with them play in passing from Hamilton's to Nambu's
dynamical picture.Comment: 27 page
High expansion coefficient glasses can be sealed to common metals
New series of high expansion coefficient glasses can be sealed by fusion onto hot surfaces of metals and alloys. Glasses have relatively low working temperatures, good chemical durability, and can be used in electrical insulators and feedthroughs to fluid or vacuum systems
- …