Mega-hemocyanin is a 13.5 MDa oxygen transporter found in snails. It is built from three stacked rings involving ten subunits each. The cryo-EM structure of the complex presented by Gatsogiannis and colleagues in this issue of Structure revealed an unexpected breaking of 5-fold symmetry in the central ring and a nonequivalent packing of the subunits.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.str.2014.12.006 | DOI Listing |
Phys Rev Lett
December 2024
Clermont INP, Institut Pascal, PHOTON-N2, Université Clermont Auvergne, CNRS, F-63000 Clermont-Ferrand, France.
The combination of an in-plane honeycomb potential and of a photonic spin-orbit coupling (SOC) emulates a photonic or polaritonic analog of bilayer graphene. We show that modulating the SOC magnitude allows us to change the overall lattice periodicity, emulating any type of moiré-arranged bilayer graphene with unique all-optical access to the moiré band topology. We show that breaking the time-reversal symmetry by an effective exciton-polariton Zeeman splitting opens a large topological gap in the array of moiré flat bands.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
University of Maryland, College Park, Joint Quantum Institute, Condensed Matter Theory Center and, Department of Physics, Maryland 20742-4111, USA.
Discrete time crystals are novel phases of matter that break the discrete time translational symmetry of a periodically driven system. In this Letter, we propose a classical system of weakly nonlinear parametrically driven coupled oscillators as a test bed to understand these phases. Such a system of parametric oscillators can be used to model period-doubling instabilities of Josephson junction arrays as well as semiconductor lasers.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
Institute for Computational Physics, University of Stuttgart, Allmandring 3, Stuttgart 70569, Germany.
The constant-pH Monte Carlo method is a popular algorithm to study acid-base equilibria in coarse-grained simulations of charge regulating soft matter systems including weak polyelectrolytes and proteins. However, the method suffers from systematic errors in simulations with explicit ions, which lead to a symmetry-breaking between chemically equivalent implementations of the acid-base equilibrium. Here, we show that this artifact of the algorithm can be corrected a-posteriori by simply shifting the pH-scale.
View Article and Find Full Text PDFWe study theoretically the quantum statistics of exciton-polaritons accumulated in two bosonic condensates linked with a coherent (Josephson) and dissipative channel. The weak lasing regime characterized by spontaneous symmetry breaking has been predicted for this system within the mean field approximation. Here we go beyond the mean field theory and show that the weak lasing regime also manifests itself in dramatic changes in the statistics of both condensates that may be revealed in measurements of the second-order coherence.
View Article and Find Full Text PDFSubwavelength light trapping in periodic structures with high quality (Q) factors is discovered to hold strong light-matter interactions for a variety of applications. Although dual-band or even multiple-band high-Q resonances are applicable to extend the operation range of a nanophotonic device, manipulating the high-Q modes individually is a necessity to implement plural intriguing applications in one system as well as optimize the capabilities across each spectrum. In this work, a novel approach is presented to independently control dual high-Q modes with distinct origins in an all-dielectric metasurface system.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!