20,786 research outputs found
KPZ equation in one dimension and line ensembles
For suitably discretized versions of the Kardar-Parisi-Zhang equation in one
space dimension exact scaling functions are available, amongst them the
stationary two-point function. We explain one central piece from the technology
through which such results are obtained, namely the method of line ensembles
with purely entropic repulsion.Comment: Proceedings STATPHYS22, Bangalore, 200
Polynuclear growth model, GOE and random matrix with deterministic source
We present a random matrix interpretation of the distribution functions which
have appeared in the study of the one-dimensional polynuclear growth (PNG)
model with external sources. It is shown that the distribution, GOE, which
is defined as the square of the GOE Tracy-Widom distribution, can be obtained
as the scaled largest eigenvalue distribution of a special case of a random
matrix model with a deterministic source, which have been studied in a
different context previously. Compared to the original interpretation of the
GOE as ``the square of GOE'', ours has an advantage that it can also
describe the transition from the GUE Tracy-Widom distribution to the GOE.
We further demonstrate that our random matrix interpretation can be obtained
naturally by noting the similarity of the topology between a certain
non-colliding Brownian motion model and the multi-layer PNG model with an
external source. This provides us with a multi-matrix model interpretation of
the multi-point height distributions of the PNG model with an external source.Comment: 27pages, 4 figure
Enviromental Implications of Växjö Municipality's Energy Requirement for New Residential Buildings
AbstractThe Växjö Municipality in Sweden sets specific energy requirements above the national building code while selling land for new residential buildings. A main energy requirement for Östra Lugnet residential area in Växjö was that all buildings must be connected to the district heating network. In this paper we analysed final energy use of the buildings, and compared the primary energy use and CO2 emission from operation of the buildings connected to district heating system with hypothetical scenarios where only air-source heat pumps were installed. The result showed that district heating is the better option from the perspective of lower carbon emission. Therefore, it seems appropriate for Växjö Municipality to set conditions for new residential buildings in Östra Lugnet to connect to the local district heating network as it contributes to its goal of low carbon society
On the stability of quantum holonomic gates
We provide a unified geometrical description for analyzing the stability of
holonomic quantum gates in the presence of imprecise driving controls
(parametric noise). We consider the situation in which these fluctuations do
not affect the adiabatic evolution but can reduce the logical gate performance.
Using the intrinsic geometric properties of the holonomic gates, we show under
which conditions on noise's correlation time and strength, the fluctuations in
the driving field cancel out. In this way, we provide theoretical support to
previous numerical simulations. We also briefly comment on the error due to the
mismatch between real and nominal time of the period of the driving fields and
show that it can be reduced by suitably increasing the adiabatic time.Comment: 7 page
Average characteristic polynomials in the two-matrix model
The two-matrix model is defined on pairs of Hermitian matrices of
size by the probability measure where
and are given potential functions and \tau\in\er. We study averages
of products and ratios of characteristic polynomials in the two-matrix model,
where both matrices and may appear in a combined way in both
numerator and denominator. We obtain determinantal expressions for such
averages. The determinants are constructed from several building blocks: the
biorthogonal polynomials and associated to the two-matrix
model; certain transformed functions and \Q_n(v); and finally
Cauchy-type transforms of the four Eynard-Mehta kernels , ,
and . In this way we generalize known results for the
-matrix model. Our results also imply a new proof of the Eynard-Mehta
theorem for correlation functions in the two-matrix model, and they lead to a
generating function for averages of products of traces.Comment: 28 pages, references adde
Prospects for cooling nanomechanical motion by coupling to a superconducting microwave resonator
Recent theoretical work has shown that radiation pressure effects can in
principle cool a mechanical degree of freedom to its ground state. In this
paper, we apply this theory to our realization of an opto-mechanical system in
which the motion of mechanical oscillator modulates the resonance frequency of
a superconducting microwave circuit. We present experimental data demonstrating
the large mechanical quality factors possible with metallic, nanomechanical
beams at 20 mK. Further measurements also show damping and cooling effects on
the mechanical oscillator due to the microwave radiation field. These data
motivate the prospects for employing this dynamical backaction technique to
cool a mechanical mode entirely to its quantum ground state.Comment: 6 pages, 6 figure
The effect of mindfulness group therapy on a broad range of psychiatric symptoms : A randomised controlled trial in primary health care
Background The need for psychotherapy in primary health care is on the increase but individual-based treatment is costly. The main aim of this randomised controlled trial (RCT) was to compare the effect of mindfulness-based group therapy (MGT) with treatment as usual (TAU), mainly individual-based cognitive behavioural therapy (CBT), on a broad range of psychiatric symptoms in primary care patients diagnosed with depressive, anxiety and/or stress and adjustment disorders. An additional aim was to compare the effect of MGT with TAU on mindful attention awareness. Methods This 8-week RCT took place in 2012 at 16 primary care centres in southern Sweden. The study population included both men and women, aged 20–64 years (n = 215). A broad range of psychiatric symptoms were evaluated at baseline and at the 8-week follow-up using the Symptom Checklist-90 (SCL-90). Mindful attention awareness was also evaluated using the Mindful Attention Awareness Scale (MAAS). Results In both groups, the scores decreased significantly for all subscales and indexes in SCL-90, while the MAAS scores increased significantly. There were no significant differences in the change in psychiatric symptoms between the two groups. The mindfulness group had a somewhat larger change in scores than the control group on the MAAS (P = 0.06, non-significant). Conclusions No significant differences between MGT and TAU, mainly individual-based CBT, were found in treatment effect. Both types of therapies could be used in primary care patients with depressive, anxiety and/or stress and adjustment disorders, where MGT has a potential to save limited resources. Trial registration ClinicalTrials.gov identifier: NCT01476371
Dynamics of a tagged particle in the asymmetric exclusion process with the step initial condition
The one-dimensional totally asymmetric simple exclusion process (TASEP) is
considered. We study the time evolution property of a tagged particle in TASEP
with the step-type initial condition. Calculated is the multi-time joint
distribution function of its position. Using the relation of the dynamics of
TASEP to the Schur process, we show that the function is represented as the
Fredholm determinant. We also study the scaling limit. The universality of the
largest eigenvalue in the random matrix theory is realized in the limit. When
the hopping rates of all particles are the same, it is found that the joint
distribution function converges to that of the Airy process after the time at
which the particle begins to move. On the other hand, when there are several
particles with small hopping rate in front of a tagged particle, the limiting
process changes at a certain time from the Airy process to the process of the
largest eigenvalue in the Hermitian multi-matrix model with external sources.Comment: 48 pages, 8 figure
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