Water exhibits rich phase behavior due to the exceptional ordering of water molecules in nanoscale confinement compared with bulk water. However, despite extensive reporting of various two-dimensional ice confined in and adsorbed on the solid surface, the role of water layer thickness in governing the formation of ordered structure under compressional confinement is still unclear. In this letter, we show the initial thickness of water layers determines the ordering behavior water confined between two graphene sheets under a compression process by using molecular-dynamics simulations. A stratification of water repeatedly occurs in the thin water layer due to the hydrogen bond network reconstruction. As a contrast, a gradually ordering occurs in the thick water layer due to a continuous hydrogen bond network optimization. A threshold thickness around 80 A is identified, above which the confined water exhibits no ordering, resembling a bulk water. The evolution of water density distribution, configuration entropy, tetrahedral order parameter, and hydrogen bond number are calculated to quantitatively define the ordering process of the confined water. Our results offer a fundamental insight into the structural ordering of water, from a highly ordered symmetry at the molecular level to the bulk-like limit, in the nano confined environment. Copyright (C) 2026 EPLA All rights, including for text and data mining, AI training, and similar technologies, are reserved.
Dissipation, or the loss of energy conservation, is necessarily related to symmetry breaking. Here we study the symmetry breaking that is responsible for dissipation in the mechanical response of amorphous solids to quasi-static strains. To this aim we consider carefully just one cycle of strain, to reveal the source of dissipation. In general the response can be conservative or dissipative, with a sharp transition between these options as a function of preparation parameters, accompanied by translation and rotational symmetry breaking and the onset of screening. We choose an example for which the mesoscopic theory can be solved exactly, and the microscopic physics can be revealed by numerical simulations. The mechanism of energy dissipation (when it exists) is explored in detail, showing that in this case it is due to the breaking of rotational symmetry. Copyright (c) 2026 EPLA
Abstract The quantum bit error rate (QBER) is a central operational parameter in quantum communication, quantifying both channel noise and the potential presence of an eavesdropper. Here we establish that, for any two-qubit state, the QBER measured across two complementary bases serves as an operational witness of nonlocality and negative conditional entropy. By invoking the Horodecki criterion for violations of the Clauser-Horne-Shimony-Holt (CHSH) inequality, we prove that an average QBER below approximately suffices to certify nonlocality. Moreover, applying entropic uncertainty relations, we show that QBER values below guarantee negative conditional entropy. We illustrate the framework with Werner and Gisin states and demonstrate its operational significance in the BBM92 QKD protocol, where parameter estimation simultaneously certifies nonlocality and negative conditional entropy. Our results therefore establish a direct connection between practical QKD parameter estimation and the certification of Bell nonlocality and negative conditional entropy.
Abstract With the advancement of global climate governance, integrating carbon trading with low-carbon technology innovation has become an important pathway for corporate emission reduction. However, existing studies often analyze carbon market behavior and technology research and development decisions separately, neglecting their interactions. To address this gap, this letter proposes a two-layer network evolutionary game model, consisting of a carbon market trading layer and a low-carbon technology research and development layer. A bidirectional feedback mechanism is introduced: cooperation in the research and development layer affects government quota allocation and changes payoffs in the carbon market layer, while competition in the carbon market layer influences firms’ willingness to cooperate in technology research and development. Simulation results show that inter-layer feedback significantly shapes the evolution of corporate strategies. Appropriate feedback intensity can promote cooperation in both layers and enhance the synergy between carbon trading and technological innovation. This model provides theoretical insights into multi-level carbon governance and offers decision-making support for optimizing carbon market and low-carbon technology policies.
