Validation of a More Reliable Method of Eye Drop Self-Administration.

SIGNIFICANCE: We propose an alternative method for eye drop self-administration. Similar IOP reductions were found with this method compared with clinician instillation. The alternative method of self-administration potentially benefits patients who have trouble successfully instilling drops. PURPOSE: The purpose of this study was to validate the efficacy of an alternative method of drop instillation. METHODS: This study is a randomized controlled crossover clinical trial. Thirty participants were recruited. A drop of 0.5% timolol maleate was instilled into subject's eye on two separate visits. On one visit, eye drop instillation was by a trained clinician, and on the other, self-instillation using an alternative method was used. The order was randomly chosen. Intraocular pressure was measured before drop instillation and 2 hours after drop instillation. The investigator was masked during measurement, and an observer recorded the IOP measurements. RESULTS: Mean ± SD IOP measurement before 0.5% timolol maleate instillation measured 13.89 ± 2.29 mmHg. An average reduction 3.75 ± 2.36 mmHg was found with clinician administration, and an average reduction of 3.32 ± 2.31 mmHg was recorded with the new method. No significance was found in IOP reduction between two groups P < .45. Percent reduction was 25.17 ± 16.21% and 24.38 ± 16.31% in clinician instillation and alternative instillation method group, respectively. No significant difference was found. This percentage reduction was similar to previously reported studies. No reported cases of eye infection or irritation were found in any case, within a 3-month follow-up period. CONCLUSIONS: We have proposed a more reliable method for instillation that provides a larger area for instillation and lessen the risk of contamination and patient's fear for eye drops. Similar efficacy was found compared with that of having a clinician directly administer the drop. This alternative method could potentially benefit patients who require topical eye drop therapy and result in increased compliance.

Quantized adiabatic transport in momentum space.

Though topological aspects of energy bands are known to play a key role in quantum transport in solid-state systems, the implications of Floquet band topology for transport in momentum space (i.e., acceleration) have not been explored so far. Using a ratchet accelerator model inspired by existing cold-atom experiments, here we characterize a class of extended Floquet bands of one-dimensional driven quantum systems by Chern numbers, reveal topological phase transitions therein, and theoretically predict the quantization of adiabatic transport in momentum space. Numerical results confirm our theory and indicate the feasibility of experimental studies.

Dissipation-enabled hydrodynamic conductivity in a tunable bandgap semiconductor.

Electronic transport in the regime where carrier-carrier collisions are the dominant scattering mechanism has taken on new relevance with the advent of ultraclean two-dimensional materials. Here, we present a combined theoretical and experimental study of ambipolar hydrodynamic transport in bilayer graphene demonstrating that the conductivity is given by the sum of two Drude-like terms that describe relative motion between electrons and holes, and the collective motion of the electron-hole plasma. As predicted, the measured conductivity of gapless, charge-neutral bilayer graphene is sample- and temperature-independent over a wide range. Away from neutrality, the electron-hole conductivity collapses to a single curve, and a set of just four fitting parameters provides quantitative agreement between theory and experiment at all densities, temperatures, and gaps measured. This work validates recent theories for dissipation-enabled hydrodynamic conductivity and creates a link between semiconductor physics and the emerging field of viscous electronics.

Carrier transport theory for twisted bilayer graphene in the metallic regime.

Understanding the normal-metal state transport in twisted bilayer graphene near magic angle is of fundamental importance as it provides insights into the mechanisms responsible for the observed strongly correlated insulating and superconducting phases. Here we provide a rigorous theory for phonon-dominated transport in twisted bilayer graphene describing its unusual signatures in the resistivity (including the variation with electron density, temperature, and twist angle) showing good quantitative agreement with recent experiments. We contrast this with the alternative Planckian dissipation mechanism that we show is incompatible with available experimental data. An accurate treatment of the electron-phonon scattering requires us to go well beyond the usual treatment, including both intraband and interband processes, considering the finite-temperature dynamical screening of the electron-phonon matrix element, and going beyond the linear Dirac dispersion. In addition to explaining the observations in currently available experimental data, we make concrete predictions that can be tested in ongoing experiments.

Kicked-Harper model versus on-resonance double-kicked rotor model: from spectral difference to topological equivalence.

Recent studies have established that, in addition to the well-known kicked-Harper model (KHM), an on-resonance double-kicked rotor (ORDKR) model also has Hofstadter's butterfly Floquet spectrum, with strong resemblance to the standard Hofstadter spectrum that is a paradigm in studies of the integer quantum Hall effect. Earlier it was shown that the quasienergy spectra of these two dynamical models (i) can exactly overlap with each other if an effective Planck constant takes irrational multiples of 2π and (ii) will be different if the same parameter takes rational multiples of 2π. This work makes detailed comparisons between these two models, with an effective Planck constant given by 2πM/N, where M and N are coprime and odd integers. It is found that the ORDKR spectrum (with two periodic kicking sequences having the same kick strength) has one flat band and N-1 nonflat bands with the largest bandwidth decaying in a power law as ~K(N+2), where K is a kick strength parameter. The existence of a flat band is strictly proven and the power-law scaling, numerically checked for a number of cases, is also analytically proven for a three-band case. By contrast, the KHM does not have any flat band and its bandwidths scale linearly with K. This is shown to result in dramatic differences in dynamical behavior, such as transient (but extremely long) dynamical localization in ORDKR, which is absent in the KHM. Finally, we show that despite these differences, there exist simple extensions of the KHM and ORDKR model (upon introducing an additional periodic phase parameter) such that the resulting extended KHM and ORDKR model are actually topologically equivalent, i.e., they yield exactly the same Floquet-band Chern numbers and display topological phase transitions at the same kick strengths. A theoretical derivation of this topological equivalence is provided. These results are also of interest to our current understanding of quantum-classical correspondence considering that the KHM and ORDKR model have exactly the same classical limit after a simple canonical transformation.