Nonlinear Polariton Fluids in a Flatband Reveal Discrete Gap Solitons

Phase frustration in periodic lattices is responsible for the formation of dispersionless flat bands. The absence of any kinetic energy scale makes flat band physics critically sensitive to perturbations and interactions. We report here on the experimental investigation of the nonlinear dynamics of cavity polaritons in the gapped flat band of a one-dimensional Lieb lattice. We observe the formation of gap solitons with quantized size and very abrupt edges, signature of the frozen propagation of switching fronts. This type of gap solitons belongs to the class of truncated Bloch waves, and had only been observed in closed systems up to now. Here the driven-dissipative character of the system gives rise to a complex multistability of the nonlinear domains generated in the flat band. These results open up interesting perspective regarding more complex 2D lattices and the generation of correlated photon phases.Comment: 6 pages, 4 figures + supplemental material (6 pages, 6 figures

Albuminuria in Diabetes Mellitus: Relation to Ambulatory Versus Office Blood Pressure and Effects of Cilazapril

This study aimed to investigate the relationship between microalbuminuria and office blood pressure (BP) as compared with ambulatory BP in patients with diabetes mellitus under everyday practice conditions. It was also undertaken to assess the effect of the angiotensin converting enzyme inhibitor cilazapril on diabetes-associated albuminuria. Ambulatory BP was recorded during daytime in 54 patients with type II diabetes mellitus at the end of a 4-week period during which they received no vasoactive drug. The difference between office and ambulatory BP was unpredictable in the individual patient. There was no significant correlation between either ambulatory or office BP and urinary albumin/ creatinine ratio. Fifty-one patients underwent a 40-week treatment with 5 mg/day of cilazapril. There was, in the absence of satisfactory BP control, the possibility of adding the calcium antagonist amlodipine (5 mg/day) from the 10th week onward and 12.5 mg/day of hydrochlorothiazide from the 20th week onward. Office mean BP was significantly reduced after 30 to 40 weeks of therapy in patients with normoalbuminuria (n = 19, − 14%, P <.001), in those with microalbuminuria (n = 22, −6.6%, P < .01), as well as in those with clinical proteinuria (n = 9, − 11.4%, P < .01). During the same time, the urinary albumin/creatinine ratio was not modified in normoalbuminuric patients (n = 19, + 24.6%, P = .72) as well as in those with clinical proteinuria (n = 9, −29.4%, P = .09). On the other hand this value was significantly reduced for the group with microalbuminuria (n = 23, −24.3%, P <.05). In the overall population, as well as in hyperalbuminuric patients (patients with microalbuminuria + patients with clinical proteinuria), the reduction of the albumin/ creatinine ratio was also significant (n = 51, −7%, P < .01 and n = 32, −25,7%, P < .01, respectively). In conclusion, the findings of this study performed by practicing physicians show that ambulatory BP may differ greatly from office BP in diabetic patients. They also indicate that urinary albumin excretion is poorly correlated with office and ambulatory BP in type II diabetics. Finally, they demonstrate the antiproteinuric action of prolonged treatment with the angiotensin converting enzyme inhibitor cilazapril, whether given alone or combined with amlodipin

Orbital angular momentum bistability in a microlaser

Light's orbital angular momentum (OAM) is an unbounded degree of freedom emerging in helical beams that appears very advantageous technologically. Using a chiral microlaser, i.e. an integrated device that allows generating an emission carrying a net OAM, we demonstrate a regime of bistability involving two modes presenting distinct OAM (L = 0 and L = 2). Furthermore, thanks to an engineered spin-orbit coupling of light in the device, these modes also exhibit distinct polarization patterns, i.e. cirular and azimuthal polarizations. Using a dynamical model of rate euqations, we show that this bistability arises from polarization-dependent saturation of the gain medium. Such a bistable regime appears very promising for implementing ultrafast optical switches based on the OAM of light. As well, it paves the way to the exploration of dynamical processes involving phase and polarization vortices