| Circuit
quantum electrodynamics in the ultrastrong-coupling
regime
T. Niemczyk, F. Deppe, H. Huebl, E. P. Menzel, F.
Hocke, M. J. Schwarz, J. J. Garcia-Ripoll, D. Zueco,
T. Hümmer, E. Solano, A. Marx and R. Gross
Nature Physics 2010
DOI: 10.1038/NPHYS1730
Light-matter interaction is one of the most fundamental
processes
in physics. It describes, for example, the exchange
of information between matter and photons. The latter,
can transfer the information to remote places. Thus,
this interaction is at the root of the technology
of communication. At the quantum level it is usually
described by dipole-dipole interaction, and it
is typically weak. Technological progress has been
able to
confine the electromagnetic field in quasi one dimensional
cavities,
allowing for strong interaction between the light
and solid state
circuits. This is what we know as circuit QED.
In this work we have measured the
strongest interaction between light and matter so
far. The coupling strength achieved in our experiment
is up 12% of the relevant energy scales in the light-matter
system. Theoretically has been predicted that at
such couplings the standard model, the Jaynes-Cummings
model breaks down. The reason is that this model
is based in the Rotating Wave approximation were
some terms are discarded. We know that these terms,
that do not conserve the number of excitations in
the total system, are important when the coupling
is sufficiently large, as in our experiment. Indeed
in our experiment we demonstrate a qualitative break
down of the model and the necessity of incorporate
these extra terms.
Far for being a curiosity, the new model demands to reconsider the protocols
for the exchange of information between light and
matter. Our work is a motivation to explore new
ways of communication between light and matter in
the ultra-strong coupling regime.
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Green
solvents from glycerol. Synthesis and physico-chemical
properties of alkyl glycerol ethers
José I. García, Héctor García-Marín,
José A. Mayoral and Pascual Pérez
Green Chem., 2010, 12,
426–434
DOI: 10.1039/b923631g
This paper was amongst the top
ten accessed on the web from the online version
of Green Chemistry in March 2010
Solvents are chemical substances
used in huge amounts for many different applications.
In many cases, organic solvents are chemical substances
derived from petrol, and have a negative impact
on the health and the environment. The use of
glycerol, which is generated as a concomitant
product in the production of biodiesel, as a renewable
source for the synthesis of less harmful and biodegradable
solvents constitutes an interesting possibility
for solvent substitution.
A family of glycerol derivatives,
consisting of more than sixty 1,3-dialkoxy-2-propanols
and 1,2,3-trialkoxypropanes, most of them not
previously described, have been synthesized, characterized,
and the possible role of these glycerol derivatives
as substitutive solvents has been evaluated through
measurements of their physico-chemical properties.
The molecular diversity of the derivatives prepared
results in significant variations of polarity
properties, facilitating the identification of
possible candidates for solvent substitution.
This will undoubtedly help to
find applications for the glycerol-derived solvents
as alternatives to the more harmful, petrol-derived,
conventional organic solvents and, even more interestingly,
to find new applications based on the particular
combination of solvent properties displayed by
some of the substances described.
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