17,865 research outputs found
Incoherent Mollow triplet
A counterpart of the Mollow triplet (luminescence lineshape of a two-level
system under coherent excitation) is obtained for the case of incoherent
excitation in a cavity. Its analytical expression, in excellent agreement with
numerical results, pinpoints analogies and differences between the conventional
resonance fluorescence spectrum and its cavity QED analogue under incoherent
excitation.Comment: 4 pages, 3 figure
On the Evolution of the Cosmic Supernova Rates
Ongoing searches for supernovae (SNe) at cosmological distances have recently
started to provide a link between SN Ia statistics and galaxy evolution. We use
recent estimates of the global history of star formation to compute the
theoretical Type Ia and Type II SN rates as a function of cosmic time from the
present epoch to high redshifts. We show that accurate measurements of the
frequency of SN events in the range 0<z<1 will be valuable probes of the nature
of Type Ia progenitors and the evolution of the stellar birthrate in the
universe. The Next Generation Space Telescope should detect of order 20 Type II
SNe per 4'x 4' field per year in the interval 1<z<4.Comment: LaTeX, 19 pages, 3 figures, to be published in the MNRA
On Core Collapse Supernovae in Normal and in Seyfert Galaxies
This paper estimates the relative frequency of different types of
core-collapse supernovae, in terms of the ratio f between the number of type
Ib--Ic and of type II supernovae. We estimate f independently for all normal
and Seyfert galaxies whose radial velocity is <=14000 km/s, and which had at
least one supernova event recorded in the Asiago catalogue from January 1986 to
August 2000. We find that the ratio f is approx. 0.23+/-0.05 in normal
galaxies. This value is consistent with constant star formation rate and with a
Salpeter Initial Mass Function and average binary rate approx. 50 %. On the
contrary, Seyfert galaxies exceed the ratio f in normal galaxies by a factor
approx. 4 at a confidence level >= 2 sigma. A caveat is that the numbers for
Seyferts are still small (6 type Ib-Ic and 6 type II supernovae discovered as
yet). Assumed real, this excess of type Ib and Ic with respect to type II
supernovae, may indicate a burst of star formation of young age (<= 20 Myr), a
high incidence of binary systems in the inner regions (r <= 0.4 R25) of Seyfert
galaxies, or a top-loaded mass function.Comment: Accepted for Publication in MNRA
How sensitive is a neutrino factory to the angle ?
We consider the impact of non-standard interactions of neutrinos (NSI) on the
determination of neutrino mixing parameters at a neutrino factory using
\pnu{e}\to\pnu{\mu} ``golden channels'' for the measurement of .
We show how a small residual NSI leads to a drastic loss in sensitivity in
, of up to two orders of magnitude. This can be somewhat overcome
if two baselines are combined.Comment: 4 pages, 3 figure
Quantitative Description of Strong-Coupling of Quantum Dots in Microcavities
We have recently developed a self-consistent theory of Strong-Coupling in the
presence of an incoherent pumping [arXiv:0807.3194] and shown how it could
reproduce quantitatively the experimental data [PRL 101, 083601 (2008)]. Here,
we summarize our main results, provide the detailed analysis of the fitting of
the experiment and discuss how the field should now evolve beyond merely
qualitative expectations, that could well be erroneous even when they seem to
be firmly established.Comment: Submitted to the AIP Conference Proceedings Series for the ICPS 2008
(Rio de Janeiro). 2 pages, reduced-quality figur
Generation of a two-photon state from a quantum dot in a microcavity under incoherent and coherent continuous excitation
We analyze the impact of both an incoherent and a coherent continuous
excitation on our proposal to generate a two-photon state from a quantum dot in
a microcavity [New J. Phys. 13, 113014 (2011)]. A comparison between exact
numerical results and analytical formulas provides the conditions to
efficiently generate indistinguishable and simultaneous pairs of photons under
both types of excitation.Comment: 10 pages, 3 figures, conference proceeding
Lasing in Strong Coupling
An almost ideal thresholdless laser can be realized in the strong-coupling
regime of light-matter interaction, with Poissonian fluctuations of the field
at all pumping powers and all intensities of the field. This ideal scenario is
thwarted by quantum nonlinearities when crossing from the linear to the
stimulated emission regime, resulting in a universal jump in the second order
coherence, which measurement could however be used to establish a standard of
lasing in strong coupling.Comment: 5 pages, 2 figure
Optimization of photon correlations by frequency filtering
Photon correlations are a cornerstone of Quantum Optics. Recent works [NJP 15
025019, 033036 (2013), PRA 90 052111 (2014)] have shown that by keeping track
of the frequency of the photons, rich landscapes of correlations are revealed.
Stronger correlations are usually found where the system emission is weak.
Here, we characterize both the strength and signal of such correlations,
through the introduction of the 'frequency resolved Mandel parameter'. We study
a plethora of nonlinear quantum systems, showing how one can substantially
optimize correlations by combining parameters such as pumping, filtering
windows and time delay.Comment: Small updates to take into account the recent experimental
observation of the physics here analyze
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