Imaging and manipulating electrons in a 1D quantum dot with Coulomb blockade microscopy

Motivated by the recent experiments by the Westervelt group using a mobile tip to probe the electronic state of quantum dots formed on a segmented nanowire, we study the shifts in Coulomb blockade peak positions as a function of the spatial variation of the tip potential, which can be termed "Coulomb blockade microscopy". We show that if the tip can be brought sufficiently close to the nanowire, one can distinguish a high density electronic liquid state from a Wigner crystal state by microscopy with a weak tip potential. In the opposite limit of a strongly negative tip potential, the potential depletes the electronic density under it and divides the quantum wire into two partitions. There the tip can push individual electrons from one partition to the other, and the Coulomb blockade micrograph can clearly track such transitions. We show that this phenomenon can be used to qualitatively estimate the relative importance of the electron interaction compared to one particle potential and kinetic energies. Finally, we propose that a weak tip Coulomb blockade micrograph focusing on the transition between electron number N=0 and N=1 states may be used to experimentally map the one-particle potential landscape produced by impurities and inhomogeneities.Comment: 4 pages 7 figure

Quantum-dot-spin single-photon interface

Using background-free detection of spin-state-dependent resonance fluorescence from a single-electron charged quantum dot with an efficiency of 0:1%, we realize a single spin-photon interface where the detection of a scattered photon with 300 picosecond time resolution projects the quantum dot spin to a definite spin eigenstate with fidelity exceeding 99%. The bunching of resonantly scattered photons reveals information about electron spin dynamics. High-fidelity fast spin-state initialization heralded by a single photon enables the realization of quantum information processing tasks such as non-deterministic distant spin entanglement. Given that we could suppress the measurement back-action to well below the natural spin-flip rate, realization of a quantum non-demolition measurement of a single spin could be achieved by increasing the fluorescence collection efficiency by a factor exceeding 20 using a photonic nanostructure

Quantum Teleportation from a Propagating Photon to a Solid-State Spin Qubit

The realization of a quantum interface between a propagating photon used for transmission of quantum information, and a stationary qubit used for storage and manipulation, has long been an outstanding goal in quantum information science. A method for implementing such an interface between dissimilar qubits is quantum teleportation, which has attracted considerable interest not only as a versatile quantum-state-transfer method but also as a quantum computational primitive. Here, we experimentally demonstrate transfer of quantum information carried by a photonic qubit to a quantum dot spin qubit using quantum teleportation. In our experiment, a single photon in a superposition state of two colors -- a photonic qubit is generated using selective resonant excitation of a neutral quantum dot. We achieve an unprecedented degree of indistinguishability of single photons from different quantum dots by using local electric and magnetic field control. To teleport a photonic qubit, we generate an entangled spin-photon state in a second quantum dot located 5 meters away from the first and interfere the photons from the two dots in a Hong-Ou-Mandel set-up. A coincidence detection at the output of the interferometer heralds successful teleportation, which we verify by measuring the resulting spin state after its coherence time is prolonged by an optical spin-echo pulse sequence. The demonstration of successful inter-conversion of photonic and semiconductor spin qubits constitute a major step towards the realization of on-chip quantum networks based on semiconductor nano-structures.Comment: 12 pages, 3 figures, Comments welcom

The role of the Th1 chemokine CXCL10 in vitiligo

Editoria

Hybrid Quantum Dot-2D Electron Gas Devices for Coherent Optoelectronics

We present an inverted GaAs 2D electron gas with self-assembled InAs quantum dots in close proximity, with the goal of combining quantum transport with quantum optics experiments. We have grown and characterized several wafers -- using transport, AFM and optics -- finding narrow-linewidth optical dots and high-mobility, single subband 2D gases. Despite being buried 500 nm below the surface, the dots are clearly visible on AFM scans, allowing precise localization and paving the way towards a hybrid quantum system integrating optical dots with surface gate-defined nanostructures in the 2D gas.Comment: 4 pages, 5 figures (color

Cytokines and HCV-related autoimmune disorders

Cytokines are intercellular mediators involved in viral control and liver damage being induced by infection with hepatitis C virus (HCV). The complex cytokine network operating during initial infection allows a coordinated, effective development of both innate and adaptive immune responses. However, HCV interferes with cytokines at various levels and escapes immune response by inducing a T-helper (Th)2/T cytotoxic 2 cytokine profile. Inability to control infection leads to the recruitment of inflammatory infiltrates into the liver parenchyma by interferon (IFN)-γ-inducible CXC chemokine ligand (CXCL)9, -10, and -11 chemokines, which results in sustained liver damage and eventually in liver cirrhosis. The most important systemic HCV-related extrahepatic diseases-mixed cryoglobulinemia, lymphoproliferative disorders, thyroid autoimmune disorders, and type 2 diabetes-are associated with a complex dysregulation of the cytokine/chemokine network, involving proinflammatory and Th1 chemokines. The therapeutical administration of cytokines such as IFN-α may result in viral clearance during persistent infection and revert this process. Theoretically agents that selectively neutralize CXCL10 could increase patient responsiveness to traditional IFN-based HCV therapy. Several studies have reported IL-28B polymorphisms and circulating CXCL10 may be a prognostic markers for HCV treatment efficacy in HCV genotype 1 infection

The effect of heavy metal on Chlorella vulgaris, Scenedesmus obliquus and Anabaena flos-aquae

In this survey two species of chlorophyta (Chlorella vulgaris and Scenedesmus obliquus) and one species of blue-green algae (Anabaena flos- aquae) were exposed with heavy metal (zinc) under lab condition (temp. 25±2°C, light 3500±350 lux) for 96 hours. After this time, these species were counted with hemocytometer and based on probit analysis method and was determined ECIO, EC50 and EC90. Amount of EC50 for C. vulgaris, S. obliquus and A. flos-aquae were 0.134,0.047 and 0.093 mg/lit, respectively and this subject was distincted that S obliquus has more endurance than other species. Max value of zinc for these species (C. vulgaris, S. obiquus and A. flos-aquae ) were 0.0134, 0.0047 and 0.0093 mg/l respectively. Regression coefficient was 92-98 percent between concentration logarithm of zinc and decrease of these species density

Increase of interferon-γ inducible α chemokine (C-X-C motif) ligand (CXCL)9 and CXCL11 serum levels in patients with active Graves' disease, and modulation by methimazole therapy.

Background: Chemokine (C-X-C motif) ligand (CXCL)9 and CXCL11 play an important role in the initial phases of autoimmune thyroiditis (AT); however their serum levels in patients with Graves'disease (GD) have never been evaluated in relation to thyroid function and treatment. Methods: To evaluate CXCL9 and CXCL11 serum levels in GD, to relate these parameters to the clinical phenotype, we measured CXCL9 and CXCL11 serum levels in 91 GD patients, 91 AT, 34 non-toxic multinodular goiters (MNG), 31 toxic nodular goiters (TNG) and 91 healthy controls (age- and sex-matched). Results: Mean CXCL9, or CXCL11, levels were higher in GD, in comparison with controls, or euthyroid AT, or MNG, or TNG (*p < 0.05, ANOVA; CXCL9: 274±265, *76±33, *132±78, *87±48, *112±56 pg/mL; CXCL11: 140±92, *64±20, 108±48, *76±33, *91±41 pg/mL; respectively). Hyperthyroid GD had significantly higher CXCL9 or CXCL11 than euthyroid or hypothyroid GD. GD with untreated hyperthyroidism had higher CXCL9 or CXCL11 than hyperthyroid or euthyroid GD under methimazole (MMI) treatment. Comparable CXCL9 and CXCL11 levels were observed in newly diagnosed untreated hyperthyroid GD vs. untreated patients with relapse of hyperthyroidism after a previous MMI course. Conclusions: Serum CXCL9, and CXCL11, levels are associated with the active phase of GD both in newly diagnosed and relapsing hyperthyroid patients. The reduction of serum CXCL9 and CXCL11 levels in treated patients with GD may be related to the immunomodulatory effects of MMI