602 research outputs found
On multiplicative functions which are small on average
Let be a completely multiplicative function that assumes values inside
the unit disc. We show that if \sum_{n2, for
some , then either is small on average or pretends to be
for some .Comment: 51 pages. Slightly strengthened Theorem 1.2 and simplified its
statement. Removed Remark 1.3. Other minor changes and corrections. To appear
in Geom. Funct. Ana
Three-player polaritons: nonadiabatic fingerprints in an entangled atom-molecule-photon system
A quantum system composed of a molecule and an atomic ensemble, confined in a
microscopic cavity, is investigated theoretically. The indirect coupling
between atoms and the molecule, realized by their interaction with the cavity
radiation mode, leads to a coherent mixing of atomic and molecular states, and
at strong enough cavity field strengths hybrid atom-molecule-photon polaritons
are formed. It is shown for the Na molecule that by changing the cavity
wavelength and the atomic transition frequency, the potential energy landscape
of the polaritonic states and the corresponding spectrum could be changed
significantly. Moreover, an unforeseen intensity borrowing effect, which can be
seen as a strong nonadiabatic fingerprint, is identified in the atomic
transition peak, originating from the contamination of the atomic excited state
with excited molecular rovibronic states
Doping a topological quantum spin liquid: slow holes in the Kitaev honeycomb model
We present a controlled microscopic study of mobile holes in the spatially
anisotropic (Abelian) gapped phase of the Kitaev honeycomb model. We address
the properties of (i) a single hole [its internal degrees of freedom as well as
its hopping properties]; (ii) a pair of holes [their (relative) particle
statistics and interactions]; (iii) the collective state for a finite density
of holes. We find that each hole in the doped model has an eight-dimensional
internal space, characterized by three internal quantum numbers: the first two
"fractional" quantum numbers describe the binding to the hole of the fractional
excitations (fluxes and fermions) of the undoped model, while the third "spin"
quantum number determines the local magnetization around the hole. The
fractional quantum numbers also encode fundamentally distinct particle
properties, topologically robust against small local perturbations: some holes
are free to hop in two dimensions, while others are confined to hop in one
dimension only; distinct hole types have different particle statistics, and in
particular, some of them exhibit non-trivial (anyonic) relative statistics.
These particle properties in turn determine the physical properties of the
multi-hole ground state at finite doping, and we identify two distinct ground
states with different hole types that are stable for different model
parameters. The respective hopping dimensionalities manifest themselves in an
electrical conductivity approximately isotropic in one ground state and
extremely anisotropic in the other one. We also compare our microscopic study
with related mean-field treatments, and discuss the main discrepancies between
the two approaches, which in particular involve the possibility of binding
fractional excitations as well as the particle statistics of the holes.Comment: 29 pages, 14 figures, published version with infinitesimal change
Robust field-dressed spectra of diatomics in an optical lattice
The absorption spectra of the cold Na2 molecule dressed by a linearly
polarized standing laser wave is investigated. In the studied scenario the
rotational motion of the molecules is frozen while the vibrational and
translational degrees of freedom are accounted for as dynamical variables. In
such a situation a light-induced conical intersection (LICI) can be formed. To
measure the spectra a weak field is used whose propagation direction is
perpendicular to the direction of the dressing field but has identical
polarization direction. Although LICIs are present in our model, the
simulations demonstrate a very robust absorption spectrum, which is insensitive
to the intensity and the wavelength of the dressing field and which does not
reflect clear signatures of light-induced nonadiabatic phenomena related to the
strong mixing between the electronic, vibration and translational motions.
However, by widening artificially the very narrow translational energy level
gaps, the fingerprint of the LICI appears to some extent in the spectrum
Quantum Control with Quantum Light of Molecular Nonadiabaticity
Coherent control experiments in molecules are often done with shaped laser
fields. The electric field is described classically and control over the time
evolution of the system is achieved by shaping the laser pulses in the time or
frequency domain. Moving on from a classical to a quantum description of the
light field allows to engineer the quantum state of light to steer chemical
processes. The quantum field description of the photon mode allows to
manipulate the light-matter interaction directly in phase-space. In this paper
we will demonstrate the basic principle of coherent control with quantum light
on the avoided crossing in lithium fluoride. Using a quantum description of
light together with the nonadiabatic couplings and vibronic degrees of freedoms
opens up new perspective on quantum control. We show the deviations from
control with purely classical light field and how back-action of the light
field becomes important in a few photon regime
Ultrafast dynamics in the vicinity of quantum light-induced conical intersections
Nonadiabatic effects appear due to avoided crossings or conical intersections
that are either intrinsic properties in field-free space or induced by a
classical laser field in a molecule. It was demonstrated that avoided crossings
in diatomics can also be created in an optical cavity. Here, the quantized
radiation field mixes the nuclear and electronic degrees of freedom creating
hybrid field-matter states called polaritons. In the present theoretical study
we go further and create conical intersections in diatomics by means of a
radiation field in the framework of cavity quantum electrodynamics (QED). By
treating all degrees of freedom, that is the rotational, vibrational,
electronic and photonic degrees of freedom on an equal footing we can control
the nonadiabatic quantum light-induced dynamics by means of conical
intersections. First, the pronounced difference between the the quantum
light-induced avoided crossing and the conical intersection with respect to the
nonadiabatic dynamics of the molecule is demonstrated. Second, we discuss the
similarities and differences between the classical and the quantum field
description of the light for the studied scenario
Molecular analysis of S-haplotypes in peach, a self-compatible Prunus species
The most commercially grown peach [Prunus persica (L.) Batsch.]
cultivars do not require cross-pollination for reasonable fruit set;
however, self-incompatibility is a well-known feature within the
Prunoideae subfamily. Isoelectric focusing and native polyacrylamide
gel electrophoresis of S-ribonucleases; PCR analyses of S-RNase and
S-haplotype-specific F-box genes as well as DNA sequencing were carried
out to survey the self- (in)compatibility allele pool and to uncover
the nature of self-compatibility in peach. From 25 cultivars and
hybrids with considerable diversity in phenotype and origin, only two
S-haplotypes were detected. Allele identity could be checked by exact
length determination of the PCR-amplified fragments and/or partial
sequencing of the peach S-1-, S-2-, and Prunus davidiana (Carr.)
Franch. S-1 RNases. S-RNases of peach were detected to possess
ribonuclease activity, and a single nucleotide polymorphism in the
S,-RNase was shown, which represents a synonymous substitution and does
not change the amino acid present at the position in the protein. A
700-bp fragment of the peach SFB gene was PCR-amplified, which is
similar to the fragment size of functional Prunus L. SFBs. All data
obtained in this study may support the contribution of genes outside
the S-locus to the self-compatible phenotype of peaches
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