The non-Abelian tensor multiplet in loop space

We introduce a non-Abelian tensor multiplet directly in the loop space associated with flat six-dimensional Minkowski space-time, and derive the supersymmetry variations for on-shell ${\cal{N}}=(2,0)$ supersymmetry.Comment: 11 pages, v2: cleaner presentation, mistakes are corrected (and an erroneous section was removed

Five-dimensional SYM from undeformed ABJM

We expand undeformed ABJM theory around the vacuum solution that was found in arxiv:0909.3101. This solution can be interpreted as a circle-bundle over a two-dimensional plane with a singularity at the origin. By imposing periodic boundary conditions locally far away from the singularity, we obtain a local fuzzy two-torus over which we have a circle fibration. By performing fluctuation analysis we obtain five-dimensional SYM with the precise value on the coupling constant that we would obtain by compactifying multiple M5 branes on the vacuum three-manifold. In the resulting SYM theory we also find a coupling to a background two-form.Comment: 23 page

Measuring current by counting electrons in a nanowire quantum dot

We measure current by counting single electrons tunneling through an InAs nanowire quantum dot. The charge detector is realized by fabricating a quantum point contact in close vicinity to the nanowire. The results based on electron counting compare well to a direct measurements of the quantum dot current, when taking the finite bandwidth of the detector into account. The ability to detect single electrons also opens up possibilities for manipulating and detecting individual spins in nanowire quantum dots

Deconstructing graviphoton from mass-deformed ABJM

Mass-deformed ABJM theory has a maximally supersymmetric fuzzy two-sphere vacuum solution where the scalar fields are proportional to the TGRVV matrices. We construct these matrices using Schwinger oscillators. This shows that the ABJM gauge group that corresponds to the fuzzy two-sphere geometry is $U(N)\times U(N-1)$. We deconstruct the graviphoton term in the D4 brane theory. The normalization of this term is fixed by topological reasons. This gives us the correct normalization of the deconstructed U(1) gauge field and fixes the Yang -Mills coupling constant to the value which corresponds to M5 brane compactified on \mb{R}^ {1,2} \times S^3/{\mb{Z}_k}. The graviphoton term also enable us to show that the zero mode contributions to the partition functions for the D4 and the M5 brane agree.Comment: 26 page

Detecting THz current fluctuations in a quantum point contact using a nanowire quantum dot

We use a nanowire quantum dot to probe high-frequency current fluctuations in a nearby quantum point contact. The fluctuations drive charge transitions in the quantum dot, which are measured in real-time with single-electron detection techniques. The quantum point contact (GaAs) and the quantum dot (InAs) are fabricated in different material systems, which indicates that the interactions are mediated by photons rather than phonons. The large energy scales of the nanowire quantum dot allow radiation detection in the long-wavelength infrared regime

On the Problem of Multiple M2 Branes

A simplified version of 3d BL theory is considered, which allows any number N of M2 branes in d=11. The underlying 3-algebra structure is provided by degenerate U(N) Nambu bracket [X,Y,Z] = tr(X) [Y,Z] + tr(Y) [Z,X] + tr(Z) [X,Y], the corresponding f^{abcd} is not totally antisymmetric and extended supersymmetry of the action remains to be checked. All the fields, including auxiliary non-propagating gauge fields, are in adjoint representation of SU(N) and the only remnant of 3-algebra structure is an octuple of gauge singlets, acquiring vacuum expectation value in transition to D2 branes in d=10.Comment: 12 page

Phagosome-lysosome fusion is a calcium-independent event in macrophages.

Phagosome-lysosome membrane fusion is a highly regulated event that is essential for intracellular killing of microorganisms. Functionally, it represents a form of polarized regulated secretion, which is classically dependent on increases in intracellular ionized calcium ([Ca2+]i). Indeed, increases in [Ca2+]i are essential for phagosome-granule (lysosome) fusion in neutrophils and for lysosomal fusion events that mediate host cell invasion by Trypanosoma cruzi trypomastigotes. Since several intracellular pathogens survive in macrophage phagosomes that do not fuse with lysosomes, we examined the regulation of phagosome-lysosome fusion in macrophages. Macrophages (M phi) were treated with 12.5 microM bis-(2-amino-S-methylphenoxy) ethane-N,N,N',N',-tetraacetic acid tetraacetoxymethyl ester (MAPT/AM), a cell-permeant calcium chelator which reduced resting cytoplasmic [Ca2+]; from 80 nM to < or = 20 nM and completely blocked increases in [Ca2+]i in response to multiple stimuli, even in the presence of extracellular calcium. Subsequently, M phi phagocytosed serum-opsonized zymosan, staphylococci, or Mycobacterium bovis. Microbes were enumerated by 4',6-diamidino-2-phenylindole, dihydrochloride (DAPI) staining, and phagosome-lysosome fusion was scored using both lysosome-associated membrane protein (LAMP-1) as a membrane marker and rhodamine dextran as a content marker for lysosomes. Confirmation of phagosome-lysosome fusion by electron microscopy validated the fluorescence microscopy findings. We found that phagosome-lysosome fusion in M phi occurs noramlly at very low [Ca2+]i (< or = 20 nM). Kinetic analysis showed that in M phi none of the steps leading from particle binding to eventual phagosome-lysosome fusion are regulated by [Ca2+]i in a rate-limiting way. Furthermore, confocal microscopy revealed no difference in the intensity of LAMP-1 immunofluorescence in phagolysosome membranes in calcium-buffered vs. control macrophages. We conclude that neither membrane recognition nor fusion events in the phagosomal pathway in macrophages are dependent on or regulated by calcium