Integrable Matrix Product States from boundary integrability

We consider integrable Matrix Product States (MPS) in integrable spin chains and show that they correspond to "operator valued" solutions of the so-called twisted Boundary Yang-Baxter (or reflection) equation. We argue that the integrability condition is equivalent to a new linear intertwiner relation, which we call the "square root relation", because it involves half of the steps of the reflection equation. It is then shown that the square root relation leads to the full Boundary Yang-Baxter equations. We provide explicit solutions in a number of cases characterized by special symmetries. These correspond to the "symmetric pairs" $(SU(N),SO(N))$ and $(SO(N),SO(D)\otimes SO(N-D))$, where in each pair the first and second elements are the symmetry groups of the spin chain and the integrable state, respectively. These solutions can be considered as explicit representations of the corresponding twisted Yangians, that are new in a number of cases. Examples include certain concrete MPS relevant for the computation of one-point functions in defect AdS/CFT.Comment: 33 pages, v2: minor corrections, references added, v3: minor modifications, v4: minor modification

Magnetic patterning of (Ga,Mn)As by hydrogen passivation

We present an original method to magnetically pattern thin layers of (Ga,Mn)As. It relies on local hydrogen passivation to significantly lower the hole density, and thereby locally suppress the carrier-mediated ferromagnetic phase. The sample surface is thus maintained continuous, and the minimal structure size is of about 200 nm. In micron-sized ferromagnetic dots fabricated by hydrogen passivation on perpendicularly magnetized layers, the switching fields can be maintained closer to the continuous film coercivity, compared to dots made by usual dry etch techniques

Correlations and diagonal entropy after quantum quenches in XXZ chains

We study quantum quenches in the XXZ spin-1/2 Heisenberg chain from families of ferromagnetic and antiferromagnetic initial states. Using Bethe ansatz techniques, we compute short-range correlators in the complete generalized Gibbs ensemble (GGE), which takes into account all local and quasi-local conservation laws. We compare our results to exact diagonalization and numerical linked cluster expansion calculations for the diagonal ensemble finding excellent agreement and thus providing a very accurate test for the validity of the complete GGE. Furthermore, we compute the diagonal entropy in the post-quench steady state. By careful finite-size scaling analyses of the exact diagonalization results, we show that the diagonal entropy is equal to one half the Yang-Yang entropy corresponding to the complete GGE. Finally, the complete GGE is quantitatively contrasted with the GGE built using only the local conserved charges (local GGE). The predictions of the two ensembles are found to differ significantly in the case of ferromagnetic initial states. Such initial states are better suited than others considered in the literature to experimentally test the validity of the complete GGE and contrast it to the failure of the local GGE

Thermodynamic symmetry resolved entanglement entropies in integrable systems

We develop a general approach to compute the symmetry-resolved Rényi and von Neumann entanglement entropies (SREE) of thermodynamic macrostates in interacting integrable systems. Our method is based on a combination of the thermodynamic Bethe ansatz and the Gärtner-Ellis theorem from large deviation theory. We derive an explicit simple formula for the von Neumann SREE, which we show to coincide with the thermodynamic Yang-Yang entropy of an effective macrostate determined by the charge sector. Focusing on the XXZ Heisenberg spin chain, we test our result against iTEBD calculations for thermal states, finding good agreement. As an application, we provide analytic predictions for the asymptotic value of the SREE following a quantum quench

Magnetic properties and domain structure of (Ga,Mn)As films with perpendicular anisotropy

The ferromagnetism of a thin GaMnAs layer with a perpendicular easy anisotropy axis is investigated by means of several techniques, that yield a consistent set of data on the magnetic properties and the domain structure of this diluted ferromagnetic semiconductor. The magnetic layer was grown under tensile strain on a relaxed GaInAs buffer layer using a procedure that limits the density of threading dislocations. Magnetometry, magneto-transport and polar magneto-optical Kerr effect (PMOKE) measurements reveal the high quality of this layer, in particular through its high Curie temperature (130 K) and well-defined magnetic anisotropy. We show that magnetization reversal is initiated from a limited number of nucleation centers and develops by easy domain wall propagation. Furthermore, MOKE microscopy allowed us to characterize in detail the magnetic domain structure. In particular we show that domain shape and wall motion are very sensitive to some defects, which prevents a periodic arrangement of the domains. We ascribed these defects to threading dislocations emerging in the magnetic layer, inherent to the growth mode on a relaxed buffer

Determining the Causal Link of Honey Bee Gut Microbial Composition on Behavioral Maturation

Emerging studies have supported the association between gut microbiome and host behaviors. However, it is unclear whether changes in the gut microbiome cause changes in host behaviors or vice versa. The European honey bee, Apis mellifera, is an excellent animal model for identifying the causal link between microbiome and behavioral changes over the lifetime of the host as the honey bee gut contains a simple microbiome composed of only nine bacterial taxa clusters. In honey bees, division of labor occurs through behavioral maturation where age determines what task a bee does. For example, older bees forage while younger bees perform brood care (nursing) and other in-hive tasks. Single cohort colonies (SCCs), or colonies composed of individuals of the same age, uncouple chronological age effects on honey bee behavioral maturation (nursing → foraging). SCCs results from our previous experiment reveal a highly significant difference in the gut microbiota between nurses and foragers, independent of age, specifically in the abundance of Lactobacillus mellis and Bifidobacterium asteroides

Renal disease in nail-patella syndrome: Clinical and morphologic studies

Renal disease in nail-patella syndrome: Clinical and morphological studies. Clinical and morphological features of seven patients with the nail-patella syndrome are described. Progression to renal failure after a prolonged period of asymptomatic proteinuria is reported. Kidney tissue from these seven patients studied by light, immunofluorescent and electron microscopy demonstrated abnormalities characteristic of this disease. Focal glomerular basement membrane thickening was observed by light microscopy. Immunofluorescent microscopy showed focal glomerular basement membrane and arteriolar staining with serum proteins, predominantly IgM and β1C. Electron microscopy revealed markedly abnormal glomerular basement membranes containing bundles of cross-striated fibrils. These fibrils were more readily demonstrated in phosphotungstic acid-stained sections. The data presented suggest that the inborn error of connective tissue metabolism of the nail-patella syndrome is associated with renal disease as the result of deposition of collagen moieties in glomerular basement membranes with subsequent alterations of glomerular structure and function

The solid state photochemistry and photophysics of a triphenylmethyl dye cyanide

Triphenylmethyl dye cyanides have been known to be sensitive to ultraviolet radiation since early in this century. Under appropriate conditions, exposure to uv leads to heteropolar fission of the C-CN bond (photoionization) and intense coloration due to dye formation. Thin homogeneous films of hexahydroxyethyl pararosaniline cyanide in a nylon matrix (Far West Technology) have been used to study the photochemistry of the dye cyanide in a solid medium and also to investigate its potential as a uv dosimeter. The dye cyanide in nylon absorbs strongly in the uv ([superscript ε] max= 6.25 x 10⁴ liter mole-¹ cm-¹ at 277 nm) and dye is produced by excitation at wavelengths < 340 nm. The dye absorbs strongly in the red region ([superscript ε] max = 7.0 x 10⁴ liter mole-¹ cm-¹ at 608 nm). The extent of photoionization may thus be determined from the optical density in the red region. In addition, the dye has been found to fluoresce when excited with a helium-neon laser at 633 nm and this property may also be used to follow the course of photolysis. The film response is reproducible, stable after exposure for many days, and dose-rate independent. However, at room temperature the partitioned quantum yield for dye formation varies from 0.4 at 260 nm to about 1 at 340 nm. Furthermore, the quantum yield is strongly dependent on the temperature during photolysis. These features limit the use of the film as an integrating actinometer for erythemal uv, but it should be valuable as a routine laboratory actinometer for monochromatic radiation. A model is presented to account for the observed photochemical behavior