18,981 research outputs found
Water does partially dissociate on the perfect TiO2(110) surface : a quantitative structure determination
There has been a long-standing controversy as to whether water can dissociate on perfect areas of a TiO2(110) surface; most early theoretical work indicated this dissociation was facile, while experiments indicated little or no dissociation. More recently the consensus of most theoretical calculations is that no dissociation occurs. New results presented here, based on analysis of scanned-energy mode photoelectron diffraction data from the OH component of O 1s photoemission, show the coexistence of molecular water and OH species in both atop (OHt) and bridging (OHbr) sites. OHbr can arise from reaction with oxygen vacancy defect sites (Ovac), but OHt have only been predicted to arise from dissociation on the perfect areas of the surface. The relative concentrations of OHt and OHbr sites arising from these two dissociation mechanisms are found to be fully consistent with the initial concentration Ovac sites, while the associated Ti-O bondlengths of the OHt and OHbr species are found to be 1.85±0.08Å and 1.94±0.07 Å, respectively
Quantum Knizhnik-Zamolodchikov equation: reflecting boundary conditions and combinatorics
We consider the level 1 solution of quantum Knizhnik-Zamolodchikov equation
with reflecting boundary conditions which is relevant to the Temperley--Lieb
model of loops on a strip. By use of integral formulae we prove conjectures
relating it to the weighted enumeration of Cyclically Symmetric Transpose
Complement Plane Partitions and related combinatorial objects
Effective Field Theory and Projective Construction for the Z_k Parafermion Fractional Quantum Hall States
The projective construction is a powerful approach to deriving the bulk and
edge field theories of non-Abelian fractional quantum Hall (FQH) states and
yields an understanding of non-Abelian FQH states in terms of the simpler
integer quantum Hall states. Here we show how to apply the projective
construction to the Z_k parafermion (Laughlin/Moore-Read/Read-Rezayi) FQH
states, which occur at filling fraction \nu = k/(kM+2). This allows us to
derive the bulk low energy effective field theory for these topological phases,
which is found to be a Chern-Simons theory at level 1 with a U(M) \times Sp(2k)
gauge field. This approach also helps us understand the non-Abelian quasiholes
in terms of holes of the integer quantum Hall states.Comment: 7 page
Magnetic hallmarks of viscous electron flow in graphene
We propose a protocol to identify spatial hallmarks of viscous electron flow
in graphene and other two-dimensional viscous electron fluids. We predict that
the profile of the magnetic field generated by hydrodynamic electron currents
flowing in confined geometries displays unambiguous features linked to
whirlpools and backflow near current injectors. We also show that the same
profile sheds light on the nature of the boundary conditions describing
friction exerted on the electron fluid by the edges of the sample. Our
predictions are within reach of vector magnetometry based on nitrogen-vacancy
centers embedded in a diamond slab mounted onto a graphene layer.Comment: 5 pages, 6 figure
Solitary versus Shock Wave Acceleration in Laser-Plasma Interactions
The excitation of nonlinear electrostatic waves, such as shock and solitons,
by ultraintense laser interaction with overdense plasmas and related ion
acceleration are investigated by numerical simulations. Stability of solitons
and formation of shock waves is strongly dependent on the velocity distribution
of ions. Monoenergetic components in ion spectra are produced by "pulsed"
reflection from solitary waves. Possible relevance to recent experiments on
"shock acceleration" is discussed.Comment: 4 pages, 4 figure
Probing the neutral edge modes in transport across a point contact via thermal effects in the Read-Rezayi non-abelian quantum Hall states
Non-abelian quantum Hall states are characterized by the simultaneous
appearance of charge and neutral gapless edge modes, with the structure of the
latter being intricately related to the existence of bulk quasi-particle
excitations obeying non-abelian statistics. In general, it is hard to probe the
neutral modes in charge transport measurements and a thermal transport
measurement seems to be inevitable. Here we propose a setup which can get
around this problem by having two point contacts in series separated by a
distance set by the thermal equilibration length of the charge mode. We show
that by using the first point contact as a heating device, the excess charge
noise measured at the second point contact carries a non-trivial signature of
the presence of the neutral mode hence leading to its indirect detection. We
also obtain explicit expressions for the thermal conductance and corresponding
Lorentz number for transport across a quantum point contact between two edges
held at different temperatures and chemical potentials
Noro-Frenkel scaling in short-range square well: A Potential Energy Landscape study
We study the statistical properties of the potential energy landscape of a
system of particles interacting via a very short-range square-well potential
(of depth ), as a function of the range of attraction to provide
thermodynamic insights of the Noro and Frenkel [ M.G. Noro and D. Frenkel,
J.Chem.Phys. {\bf 113}, 2941 (2000)] scaling. We exactly evaluate the basin
free energy and show that it can be separated into a {\it vibrational}
(-dependent) and a {\it floppy} (-independent) component. We
also show that the partition function is a function of ,
explaining the equivalence of the thermodynamics for systems characterized by
the same second virial coefficient. An outcome of our approach is the
possibility of counting the number of floppy modes (and their entropy).Comment: 4 pages, 4 figures accepted for publication on PR
Boundary correlation function of fixed-to-free bcc operators in square-lattice Ising model
We calculate the boundary correlation function of fixed-to-free boundary
condition changing operators in the square-lattice Ising model. The correlation
function is expressed in four different ways using block Toeplitz
determinants. We show that these can be transformed into a scalar Toeplitz
determinant when the size of the matrix is even. To know the asymptotic
behavior of the correlation function at large distance we calculate the
asymptotic behavior of this scalar Toeplitz determinant using the Szeg\"o's
theorem and the Fisher-Hartwig theorem. At the critical temperature we confirm
the power-law behavior of the correlation function predicted by conformal field
theory
Open boundary Quantum Knizhnik-Zamolodchikov equation and the weighted enumeration of Plane Partitions with symmetries
We propose new conjectures relating sum rules for the polynomial solution of
the qKZ equation with open (reflecting) boundaries as a function of the quantum
parameter and the -enumeration of Plane Partitions with specific
symmetries, with . We also find a conjectural relation \`a la
Razumov-Stroganov between the limit of the qKZ solution and refined
numbers of Totally Symmetric Self Complementary Plane Partitions.Comment: 27 pages, uses lanlmac, epsf and hyperbasics, minor revision
The solution of the quantum T-system for arbitrary boundary
We solve the quantum version of the -system by use of quantum
networks. The system is interpreted as a particular set of mutations of a
suitable (infinite-rank) quantum cluster algebra, and Laurent positivity
follows from our solution. As an application we re-derive the corresponding
quantum network solution to the quantum -system and generalize it to
the fully non-commutative case. We give the relation between the quantum
-system and the quantum lattice Liouville equation, which is the quantized
-system.Comment: 24 pages, 18 figure
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