9 research outputs found
Analysis of a single-atom dipole trap
We describe a simple experimental technique which allows to store a single
Rubidium 87 atom in an optical dipole trap. Due to light-induced two-body
collisions during the loading stage of the trap the maximum number of captured
atoms is locked to one. This collisional blockade effect is confirmed by the
observation of photon anti-bunching in the detected fluorescence light. The
spectral properties of single photons emitted by the atom were studied with a
narrow-band scanning cavity. We find that the atomic fluorescence spectrum is
dominated by the spectral width of the exciting laser light field. In addition
we observe a spectral broadening of the atomic fluorescence light due to the
Doppler effect. This allows us to determine the mean kinetic energy of the
trapped atom corresponding to a temperature of 105 micro Kelvin. This simple
single-atom trap is the key element for the generation of atom-photon
entanglement required for future applications in quantum communication and a
first loophole-free test of Bell's inequality.Comment: Version 2; formula in equ. 3 correcte
Towards a loophole-free test of Bell's inequality with entangled pairs of neutral atoms
Experimental tests of Bell's inequality allow to distinguish quantum
mechanics from local hidden variable theories. Such tests are performed by
measuring correlations of two entangled particles (e.g. polarization of photons
or spins of atoms). In order to constitute conclusive evidence, two conditions
have to be satisfied. First, strict separation of the measurement events in the
sense of special relativity is required ("locality loophole"). Second, almost
all entangled pairs have to be detected (for particles in a maximally entangled
state the required detector efficiency is 82.8%), which is hard to achieve
experimentally ("detection loophole"). By using the recently demonstrated
entanglement between single trapped atoms and single photons it becomes
possible to entangle two atoms at a large distance via entanglement swapping.
Combining the high detection efficiency achieved with atoms with the space-like
separation of the atomic state detection events, both loopholes can be closed
within the same experiment. In this paper we present estimations based on
current experimental achievements which show that such an experiment is
feasible in future.Comment: 6 pages, 3 figures, to be published in Advanced Science Letter
Keratinocyte-intrinsic BCL10/MALT1 activity initiates and amplifies psoriasiform skin inflammation
Psoriasis is a chronic inflammatory skin disease arising from poorly defined pathological cross-talk between keratinocytes and the immune system. BCL10 (B cell lymphoma/leukemia 10) and MALT1 (mucosa-associated lymphoid tissue lymphoma translocation protein 1) are ubiquitously expressed inflammatory signaling proteins that can interact with the psoriasis susceptibility factor CARD14, but their functions in psoriasis are insufficiently understood. We report that although keratinocyte-intrinsic BCL10/MALT1 deletions completely rescue inflammatory skin pathology triggered by germline Card14 gain-of-function mutation in mice, the BCL10/MALT1 signalosome is unexpectedly not involved in the CARD14-dependent interleukin-17 receptor (IL-17R) proximal pathway. Instead, it plays a more pleiotropic role by amplifying keratinocyte responses to a series of inflammatory cytokines, including IL-17A, IL-1 beta, and TNF. Moreover, selective keratinocyte-intrinsic activation of BCL10/MALT1 signaling with an artificial engager molecule is sufficient to initiate lymphocyte-mediated psoriasiform skin inflammation, and aberrant BCL10/MALT1 activity is frequently detected in the skin of human sporadic psoriasis. Together, these results establish that BCL10/MALT1 signalosomes can act as initiators and crucial amplifiers of psoriatic skin inflammation and indicate a critical function for this complex in sporadic psoriasis
Strong Coupling between Single Atoms and Nontransversal Photons
Light is often described as a fully transverse-polarized wave, i.e., with an electric field vector that is orthogonal to the direction of propagation. However, light confined in dielectric structures such as optical waveguides or whispering-gallery-mode microresonators can have a strong longitudinal polarization component. Here, using single Rb-85 atoms strongly coupled to a whispering-gallery-mode microresonator, we experimentally and theoretically demonstrate that the presence of this longitudinal polarization fundamentally alters the interaction between light and matter
Chiral quantum optics
At the most fundamental level, the interaction between light and matter is
manifested by the emission and absorption of single photons by single quantum
emitters. Controlling light--matter interaction is the basis for diverse
applications ranging from light technology to quantum--information processing.
Many of these applications are nowadays based on photonic nanostructures
strongly benefitting from their scalability and integrability. The confinement
of light in such nanostructures imposes an inherent link between the local
polarization and propagation direction of light. This leads to {\em chiral
light--matter interaction}, i.e., the emission and absorption of photons depend
on the propagation direction and local polarization of light as well as the
polarization of the emitter transition. The burgeoning research field of {\em
chiral quantum optics} offers fundamentally new functionalities and
applications both for single emitters and ensembles thereof. For instance, a
chiral light--matter interface enables the realization of integrated
non--reciprocal single--photon devices and deterministic spin--photon
interfaces. Moreover, engineering directional photonic reservoirs opens new
avenues for constructing complex quantum circuits and networks, which may be
applied to simulate a new class of quantum many--body systems
Haematological effects of oral administration of bitopertin, a glycine transport inhibitor, in patients with non‐transfusion‐dependent β‐thalassaemia
Bitopertin is a small molecule selective inhibitor of glycine transporter 1 (GlyT1), initially developed to increase brain extracellular levels of glycine in the vicinity of neuronal N-methyl-D-aspartate receptors for the treatment of schizophrenia. GlyT1, the pharmacological target of bitopertin, is also present as a transmembrane transporter in erythroid cells1 and accounts for 50–55% of glycine uptake in human red blood cells (RBCs).2, 3 Erythroid GlyT1 inhibition by bitopertin leads to reduced intracellular glycine availability, interfering with the first step of haem synthesis, in which 5-aminolevulinate synthase catalyses the condensation reaction between glycine and succinyl-coenzyme A, forming 5-aminolevulinic acid.