504 research outputs found
Joining-splitting interaction of non-critical string
The joining--splitting interaction of non-critical bosonic string is analyzed
in the light-cone formulation. The Mandelstam method of constructing tree
string amplitudes is extended to the bosonic massive string models of the
discrete series. The general properties of the Liouville longitudinal
excitations which are necessary and sufficient for the Lorentz covariance of
the light-cone amplitudes are derived. The results suggest that the covariant
and the light-cone approach are equivalent also in the non-critical dimensions.
Some aspects of unitarity of interacting non-critical massive string theory are
discussed.Comment: 38 pages, 4 embedded figures, discussion in the Introduction
clarified, Appendix D and some material from Section 5 remove
Phonon-assisted relaxation between hole states in quantum dot molecules
We study theoretically phonon-assisted relaxation and inelastic tunneling of
holes in a double quantum dot. We derive hole states and relaxation rates from
kp Hamiltonians and show that there is a finite distance between the dots where
lifetimes of hole states are very long which is related to vanishing tunnel
coupling. We show also that the light hole admixture to hole states can
considerably affect the hole relaxation rates even though its magnitude is very
small
Topologically confined states at corrugations of gated bilayer graphene
We investigate the electronic and transport properties of gated bilayer
graphene with one corrugated layer, which results in a stacking AB/BA boundary.
When a gate voltage is applied to one layer, topologically protected gap states
appear at the corrugation, which reveal as robust transport channels along the
stacking boundary. With increasing size of the corrugation, more localized,
quantum-well-like states emerge. These finite-size states are also conductive
along the fold, but in contrast to the stacking boundary states, which are
gapless, they present a gap. We have also studied periodic corrugations in
bilayer graphene; our findings show that such corrugations between AB- and
BA-stacked regions behave as conducting channels that can be easily identified
by their shape
D.A.F. de Sade – "Divine Marquis" or demolisher of the ideas of Enlightment
The paper provides a brief outline of the major elements that made up the foundations for the political thought of Marquis D. A. F. de Sade. The author of the paper believes that these elements have not been sufficiently presented in the Polish historiography of political doctrines. The Marquis, being deeply anchored in the Enlightenment ideas and stylistics, was simultaneously the thinker who questioned a remarkable number of elements of these ideas. What he challenged were in particular: the previous descriptions of nature, natural state, location and status of the human being, social contract and the concept of State and law. By questioning these concepts he indirectly challenged also the major articles of the Declaration of Rights of Man and Citizen. His political concepts are detectable in most of his literary production and therefore the author of the paper treats what is detectable as a certain whole which perhaps is not fully consistent of morality and law, both those of ancien régime as well as those promoted by too idealistic concepts of the pre-revolutionary era. An interesting example of the originality of his way of political thinking was his attempt to present to the reader the two extremely different socio-constitutional models – that of classical Utopia and that of Anti-utopia – as included in one literary production. The essay is concluded with a brief attempt at the summarizing and assessing of the discussed concepts as viewed against our present-day reception of de Sade’s production and his location in the history of political thought
Light-cone formulation and spin spectrum of non-critical fermionic string
A free fermionic string quantum model is constructed directly in the
light-cone variables in the range of dimensions . It is shown that
after the GSO projection this model is equivalent to the fermionic massive
string and to the non-critical Rammond-Neveu-Schwarz string. The spin spectrum
of the model is analysed. For the character generating functions is
obtained and the particle content of first few levels is numerically
calculated.Comment: 13 page
Electronic structure of defected trilayer graphene
Wersja opublikowana DOI: https://doi.org/10.1080/00268976.2021.2013554Gated trilayer graphene shows energy gap and three topologically protected gaplessstates when the stacking order changes from ABC to CBA. Here we such
a trilayer, but with a part of the internal layer cut and removed forming a region in
trilayer built of only two not connected single graphene layers. We demonstrate that
the electronic structure of this region is almost the same as of the gated trilayer.
Curiously, the topological gapless states that appear due to difference in the stacking order of the adjacent trilayers localize mostly in these single graphene layers. Thus, strong disorder in the internal layer of gated trilayer graphene does not lead to destruction of its fundamental electronic properties
Static Quark Potential from the Polyakov Sum over Surfaces
Using the Polyakov string ansatz for the rectangular Wilson loop we calculate
the static potential in the semiclassical approximation. Our results lead to a
well defined sum over surfaces in the range .Comment: 17 pages, (with a TeX error on the title page corrected - nothing
else changed
Interface States in Carbon Nanotube Junctions: Rolling up graphene
We study the origin of interface states in carbon nanotube intramolecular
junctions between achiral tubes. By applying the Born-von Karman boundary
condition to an interface between armchair- and zigzag-terminated graphene
layers, we are able to explain their number and energies. We show that these
interface states, costumarily attributed to the presence of topological
defects, are actually related to zigzag edge states, as those of graphene
zigzag nanoribbons. Spatial localization of interface states is seen to vary
greatly, and may extend appreciably into either side of the junction. Our
results give an alternative explanation to the unusual decay length measured
for interface states of semiconductor nanotube junctions, and could be further
tested by local probe spectroscopies
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