Topological systems are inherently robust to disorder and continuous perturbations, resulting in dissipation-free edge transport of electrons in quantum solids, or reflectionless guiding of photons ...and phonons in classical wave systems characterized by topological invariants. Recently, a new class of topological materials characterized by bulk polarization has been introduced, and was shown to host higher-order topological corner states. Here, we demonstrate theoretically and experimentally that 3D-printed two-dimensional acoustic meta-structures can possess nontrivial bulk topological polarization and host one-dimensional edge and Wannier-type second-order zero-dimensional corner states with unique acoustic properties. We observe second-order topological states protected by a generalized chiral symmetry of the meta-structure, which are localized at the corners and are pinned to 'zero energy'. Interestingly, unlike the 'zero energy' states protected by conventional chiral symmetry, the generalized chiral symmetry of our three-atom sublattice enables their spectral overlap with the continuum of bulk states without leakage. Our findings offer possibilities for advanced control of the propagation and manipulation of sound, including within the radiative continuum.
Open physical systems can be described by effective non-Hermitian Hamiltonians that characterize the gain or loss of energy or particle numbers from the system. Experimental realization of optical1–7 ...and mechanical8–13 non-Hermitian systems has been reported, demonstrating functionalities such as lasing14–16, topological features7,17–19, optimal energy transfer20,21 and enhanced sensing22,23. Such realizations have been limited to classical (wave) systems in which only the amplitude information, not the phase, is measured. Thus, the effects of a systems’s proximity to an exceptional point—a degeneracy of such non-Hermitian Hamiltonians where the eigenvalues and corresponding eigenmodes coalesce24–29—on its quantum evolution remain unexplored. Here, we use post-selection on a three-level superconducting transmon circuit to carry out quantum state tomography of a single dissipative qubit in the vicinity of its exceptional point. We observe the spacetime reflection symmetry-breaking transition30,31 at zero detuning, decoherence enhancement at finite detuning and a quantum signature of the exceptional point in the qubit relaxation state. Our experiments show phenomena associated with non-Hermitian physics such as non-orthogonality of eigenstates in a fully quantum regime, which could provide a route to the exploration and harnessing of exceptional point degeneracies for quantum information processing.
A grand challenge in materials research is to understand complex electronic correlation and non-equilibrium atomic interactions, and how such intrinsic properties and dynamic processes affect energy ...transfer and defect evolution in irradiated materials. Here we report that chemical disorder, with an increasing number of principal elements and/or altered concentrations of specific elements, in single-phase concentrated solid solution alloys can lead to substantial reduction in electron mean free path and orders of magnitude decrease in electrical and thermal conductivity. The subsequently slow energy dissipation affects defect dynamics at the early stages, and consequentially may result in less deleterious defects. Suppressed damage accumulation with increasing chemical disorder from pure nickel to binary and to more complex quaternary solid solutions is observed. Understanding and controlling energy dissipation and defect dynamics by altering alloy complexity may pave the way for new design principles of radiation-tolerant structural alloys for energy applications.
•Initial granular topologies drastically affect the time-bandwidth results.•Optimal particle impact dampers work effectively over a broad energy range.•High nonlinear bandwidth is got by using ...multiple granules in collect-and-collect regime.•Time-bandwidth limit is broken owing to inelastic collisions and frictional effects.
The dissipative capacity as quantified by the nonlinear bandwidth measure of impulsively loaded linear primary resonators or primary structures (PSs) coupled to particle impact dampers (PIDs) is assessed. The considered PIDs are designed by initially placing different numbers of spherical, linearly viscoelastic granules at various 2D initial topologies and clearances. The strongly nonlinear and highly discontinuous dynamics of the PIDs are simulated via the discrete element method taking Hertzian interactions, slipping friction caused by granular rotations into account. An extended definition of nonlinear bandwidth is used to evaluate the energy dissipation capacity of the integrated PS-PID systems. To this end, the time-bandwidth (T-B) product is defined by nonlinear bandwidth in tandem with characteristic time. The T-B product is studied as a measure of the capacity of these systems to store or dissipate vibration energy. It is found that the initial topologies of the granules in the PID drastically affect the T-B product, which, depending on shock intensity, may break the classical limit of unity of linear time-invariant dissipative resonators. The optimal PS-PID systems composed of multiple granules produce large nonlinear bandwidths, indicating strong dissipative capacity of broadband input energy by the PIDs. Moreover, the granular collect-and-collide regime yields high nonlinear bandwidth and efficient energy dissipation capacity, whereas the opposite is observed for the granular gaseous state regime. The relationship between energy dissipation by the PID and nonlinear bandwidth of the PS are discussed, and it is found that as the shock intensity increases these two measures tend to vary similarly. The implications of these findings on the study of the dissipative capacity of the PS-PID system are discussed, yielding a predictive methodology for designing PIDs to act as highly effective nonlinear energy sinks capable of rapid and efficient suppression of vibration induced by shocks.
Physical systems powering motion and creating structure in a fixed amount of time dissipate energy and produce entropy. Whether living, synthetic or engineered, systems performing these dynamic ...functions must balance dissipation and speed. Here, we show that rates of energy and entropy exchange are subject to a speed limit—a time–information uncertainty relation—imposed by the rates of change in the information content of the system. This uncertainty relation bounds the time that elapses before the change in a thermodynamic quantity has the same magnitude as its s.d. From this general bound, we establish a family of speed limits for heat, dissipated/chemical work and entropy depending on the experimental constraints on the system and its environment. In all of these inequalities, the timescale of transient dynamical fluctuations is universally bounded by the Fisher information. Moreover, they all have a mathematical form that mirrors the Mandelstam–Tamm version of the time–energy uncertainty relation in quantum mechanics. These bounds on the speed of arbitrary observables apply to transient systems away from thermodynamic equilibrium, independent of the physical constraints on the stochastic dynamics or their function.A time–information uncertainty relation in thermodynamics has been derived, analogous to the time–energy uncertainty relation in quantum mechanics, imposing limits on the speed of energy and entropy exchange between a system and external reservoirs.
Landauer’s Principle at Zero Temperature Timpanaro, André M.; Santos, Jader P.; Landi, Gabriel T.
Physical review letters,
06/2020, Letnik:
124, Številka:
24
Journal Article
Recenzirano
Odprti dostop
Landauer's bound relates changes in the entropy of a system with the inevitable dissipation of heat to the environment. The bound, however, becomes trivial in the limit of zero temperature. Here we ...show that it is possible to derive a tighter bound which remains nontrivial even as T → 0 . As in the original case, the only assumption we make is that the environment is in a thermal state. Nothing is said about the state of the system or the kind of system-environment interaction. Our bound is valid for all temperatures and is always tighter than the original one, tending to it in the limit of high temperatures.
Photocatalysis is a green technology to use ubiquitous and intermittent sunlight. The emerging S‐scheme heterojunction has demonstrated its superiority in photocatalysis. This article covers the ...state‐of‐the‐art progress and provides new insights into its general designing criteria. It starts with the challenges confronted by single photocatalyst from the perspective of energy dissipation by borrowing the common behaviors in the dye molecule. Subsequently, other problems faced by single photocatalyst are summarized. Then a viable solution for these problems is the construction of heterojunctions. To overcome the problems and mistakes of type‐II and Z‐scheme heterojunctions, S‐scheme heterojunction is proposed and the underlying reaction mechanism is summarized. Afterward, the design principles for S‐scheme heterojunction are proposed and four types of S‐scheme heterojunctions are suggested. Following this, direct characterization techniques for testifying the charge transfer in S‐scheme heterojunction are presented. Finally, different photocatalytic applications of S‐scheme heterojunctions are summarized. Specifically, this work endeavors to clarify the critical understanding on curved Fermi level in S‐scheme heterojunction interface, which can help strengthen and advance the fundamental theories of photocatalysis. Moreover, the current challenges and prospects of the S‐scheme heterojunction photocatalyst are critically discussed.
Emerging S‐scheme heterojunction has demonstrated its superiority in photocatalysis. This article covers the state‐of‐the‐art progress of S‐scheme heterojunction. Design principles for S‐scheme heterojunction are proposed and four types of S‐scheme heterojunctions are suggested. Direct characterization methods for electron transfer in S‐scheme heterojunction are presented. Different photocatalytic applications are summarized. Especially, the curved Fermi level in S‐scheme heterojunction interface is discussed.
•We derive that Cahn–Hilliard equation possesses a local energy dissipation law (LEDL).•Based on the observation, three LEDL schemes for the CH equation are derived.•Three schemes are independent of ...boundary conditions.•Such schemes are proven to conserve the LEDL in any local region.•Our schemes hold the total energy stable laws and the mass laws.
In this paper, we show that the Cahn–Hilliard equation possesses a local energy dissipation law, which is independent of boundary conditions and produces much more information of the original problem. To inherit the intrinsic property, we derive three novel local structure-preserving algorithms for the 2D Cahn–Hilliard equation by the concatenating method. In particular, when the nonlinear bulk potential f(ϕ) in the equation is chosen as the Ginzburg–Landau double-well potential, the method discussed by Zhang and Qiao (2012) 50 is a special case of our scheme II. Thanks to the Leibnitz rules and properties of operators, the three schemes are rigorously proven to conserve the discrete local energy dissipation law in any local time–space region. Under periodic boundary conditions, the schemes are proven to possess the discrete mass conservation and total energy dissipation laws. Numerical experiments are conducted to show the performance of the proposed schemes.
A controllable plastic hinge with bending moment-shear separation was developed according to the design concept of an earthquake-resilient structure using replaceable multi-slit energy dissipation ...devices. Furthermore, a novel precast concrete beam-column joint was proposed to achieve repair of the post-earthquake damage in prefabricated structures. Pseudo-static cyclic loading tests were conducted on three precast concrete exterior beam-column joints and one conventional monolithic joint specimen to investigate the seismic performance and validate the effectiveness of the proposed joint. The results revealed that when the maximum flexural capacity of the precast joint was close to that of the monolithic joint, the precast joints exhibited better seismic performance in terms of ductility, deformation, and energy dissipation capacity than that of the monolithic joint. Furthermore, the damage and failure of the precast joints were mainly concentrated in the multi-slit energy dissipation device. In contrast, the precast concrete beam and column components remained elastic, allowing for the control of damage locations at the precast joint and facilitating efficient post-earthquake repair. Finally, a theoretical relationship was established between the flexural capacity and deformation of the connection zone in the precast joint, serving as a theoretical reference for the design of multi-slit energy dissipation devices and shear connection keys.
•A new type of earthquake resilient precast joint is presented and investigated.•A connection form of plastic hinge with bending moment-shear separation is developed.•The theoretical method of the proposed bending moment-shear separation hinge is established.
High‐performance damping materials are significant toward reducing vibration and maintaining stability for industrial applications. Herein, a yolk–shell piezoelectric damping mechanism is reported, ...which can enhance mechanical energy dissipation and improve damping capability. With the addition of yolk–shell particles and carbon nanotube (CNT) conductive network, damping properties of various resin matrices are enhanced with the energy dissipation path of mechanical to electrical to heat energy. Particularly, the peak loss factor of epoxy composites reaches 1.91 and tan δ area increases by 25.72% at 20 °C. The results prove the general applicability of yolk–shell piezoelectric damping mechanism. Besides, the novel damping materials also exhibit excellent flexibility, stretchability, and resilience, offering a promising application toward damping coating, indicating broad scope of application in transportation and sophisticated electronics, etc.
A yolk–shell piezoelectric damping mechanism is demonstrated to enhance the energy dissipation path of mechanical to electrical to heat and improve damping capability. The strategy of introducing yolk–shell nanoparticles and conductive network applies to various resin matrix exhibits a significant enhancement effect, providing a facile and effective path to improve damping performance and reduce vibration for broad application prospects.
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