38,017 research outputs found
Unveiling the Effect of Magnetic Noise in the Coherence of Single-Molecule Quantum Processors
Quantum bits (qubits) constitute the most elementary building-blocks of any quantum technology, where information is stored and processed in the form of quantum superpositions between discrete energy levels. In particular, the fabrication of quantum processors is a key long-term goal that will allow us conducting specific tasks much more efficiently than the most powerful classical computers can do. Motivated by recent experiments in which three addressable spin qubits are defined on a potential single-molecule quantum processor, namely the [Gd(H2O)P5W30O110]12− polyoxometalate, we investigate the decohering effect of magnetic noise on the encoded quantum information. Our state-of-the-art model, which provides more accurate results than previous estimates, show a noticeable contribution of magnetic noise in limiting the survival timescale of the qubits. Yet, our results suggest that it might not be the only dephasing mechanism at play but other mechanisms, such as lattice vibrations and physical movement of magnetic nuclei, must be considered to understand the whole decoherence process
On the logarithmic comparison theorem for integrable logarithmic connections
Let be a complex analytic manifold, a free divisor with
jacobian ideal of linear type (e.g. a locally quasi-homogeneous free divisor),
the corresponding open inclusion, an integrable
logarithmic connection with respect to and the local system of the
horizontal sections of on . In this paper we prove that the canonical
morphisms between the logarithmic de Rham complex of and
(resp. the logarithmic de Rham complex of and ) are isomorphisms
in the derived category of sheaves of complex vector spaces for
(locally on )Comment: Terminology has changed: "linear jacobian type" instead of
"commutative differential type"); no Koszul hypothesis is needed in theorem
(2.1.1); minor changes. To appear in Proc. London Math. So
Wavelength de-multiplexing properties of a single aperture flanked by periodic arrays of indentations
In this paper we explore the transmission properties of single subwavelength
apertures perforated in thin metallic films flanked by asymmetric
configurations of periodic arrays of indentations. It is shown how the
corrugation in the input side can be used to transmit selectively only two
different wavelengths. Also, by tuning the geometrical parameters defining the
corrugation of the output side, these two chosen wavelengths can emerge from
the structure as two very narrow beams propagating at well-defined directions.
This new ability of structured metals can be used as a base to build
micron-sized wavelength de-multiplexers.Comment: Accepted for publication in Photonics and Nanostructure
On the transmission of light through a single rectangular hole
In this Letter we show that a single rectangular hole exhibits transmission
resonances that appear near the cutoff wavelength of the hole waveguide. For
light polarized with the electric field pointing along the short axis, it is
shown that the normalized-to-area transmittance at resonance is proportional to
the ratio between the long and short sides, and to the dielectric constant
inside the hole. Importantly, this resonant transmission process is accompanied
by a huge enhancement of the electric field at both entrance and exit
interfaces of the hole. These findings open the possibility of using
rectangular holes for spectroscopic purposes or for exploring non-linear
effects.Comment: Submitted to PRL on Feb. 9th, 200
Numerical modelling of non-ionic microgels: an overview
Microgels are complex macromolecules. These colloid-sized polymer networks
possess internal degrees of freedom and, depending on the polymer(s) they are
made of, can acquire a responsiveness to variations of the environment
(temperature, pH, salt concentration, etc.). Besides being valuable for many
practical applications, microgels are also extremely important to tackle
fundamental physics problems. As a result, these last years have seen a rapid
development of protocols for the synthesis of microgels, and more and more
research has been devoted to the investigation of their bulk properties.
However, from a numerical standpoint the picture is more fragmented, as the
inherently multi-scale nature of microgels, whose bulk behaviour crucially
depends on the microscopic details, cannot be handled at a single level of
coarse-graining. Here we present an overview of the methods and models that
have been proposed to describe non-ionic microgels at different length-scales,
from the atomistic to the single-particle level. We especially focus on
monomer-resolved models, as these have the right level of details to capture
the most important properties of microgels, responsiveness and softness. We
suggest that these microscopic descriptions, if realistic enough, can be
employed as starting points to develop the more coarse-grained representations
required to investigate the behaviour of bulk suspensions
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