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We explore a topology-localization phase diagram by simulating a one-dimensional Su-Schrieffer-Heeger model with quasiperiodic disorder using a programmable superconducting simulator. We experimentally map out and identify various trivial and topological phases with extended, critical, and localized bulk states. We find that with increasing disorder strength, some extended states can be first replaced by localized states and then by critical states before the system finally becomes fully localized. The critical states exhibit typical features such as multifractality and self-similarity, which lead to surprisingly rich phases with different types of mobility edges and scaling behaviors on the phase boundaries. Our results shed light on the investigation of the topological and localization phenomena in condensed-matter physics.

The vehicle industry is currently developing toward using new ecologically-friendly energy. Although the energy density of compressed air is not high, it is very ecologically friendly and can be used as a power source to drive vehicles. Therefore, it should still have application prospects in some specific applications. The purpose of this paper is to fill the gap in the research field of high torque CAE for a large vehicle and explore the application possibility of CAE in the field of new energy vehicles for public transportation. A four-stroke six-cylinder high torque CAE (Compressed Air Engine) was proposed. The calculation model of this CAE was constructed, the dynamic characteristics were theoretically analyzed, a prototype engine was manufactured and tested on the engine bench system, and the on-road test of the bus equipped with CAE was carried out. The results show that CAE has the characteristics of obtaining more significant torque at low speed. The bench test results of torque and power are in line with the changing trend of CAE dynamic performance predicted by calculation. When the inflation pressure of the prototype is 10 MPa, and the rotational speed is 650 r/min, the effective torque can reach 1032.48 N m. The CAE bus runs very stably during the on-road test. It can maintain a 60–80 km range with a load of 18 tons and a maximum speed of 69 km/h. The research of this paper can show that the compressed air engine with high power output shows excellent characteristics from theoretical analysis to vehicle tests. It is possible to use CAE to drive vehicles in new energy public transportation in the future.

Stimulated Raman adiabatic passage is a robust approach to realize high-fidelity state transfer, but requires long operation. Here, the authors propose a shortcut-to-adiabatic protocol to speed up such approach by modifying the Raman pulses, and demonstrate it in a cold atomic setup.

Cold atomic gases in a hexagonal optical lattice is a highly effective quantum simulator for exploring graphenelike physics. In this paper, we propose a feasible scheme to simulate and detect the Majorana dynamics with cold atoms in a bilayer hexagonal lattice. We explore the dynamics of a general Majorana particle, in which three key observables featuring the Majorana dynamics are studied, which include the pseudoenergy, orthogonality, and the fidelity. The results reveal that the fidelity is a good observable to distinguish Majorana from Dirac or Weyl dynamics. Through the decomposition of the Majorana equation, we address the Majorana Zitterbewegung, which is indeed the addition of two Dirac Zitterbewegung. Finally, we present a method to detect the Majorana dynamics with the quantum-state tomography implemented with quenches. Our scheme may provide an avenue for observing the phenomena described by the Majorana equation through bilayer graphene lattices.

Although Weyl semimetals have been extensively studied for exploring rich topological physics, the direct observation of the celebrated chiral magnetic effect (CME) associated with the so-called dipolar chiral anomaly has long intrigued and challenged physicists, still remaining elusive in nature. Here we propose a feasible scheme for experimental implementation of ultracold atoms that may enable us to probe the CME with a pure topological current in an artificial Weyl semimetal. The paired Weyl points with the dipolar chiral anomaly emerge in the presence of the well-designed spin-orbital coupling and laser-assisted tunneling. Both of the two artificial fields are readily realizable and highly tunable via current optical techniques using ultracold atoms trapped in three-dimensional optical lattices, providing a reliable way for manipulating Weyl points in the momentum-energy space. By applying a weak artificial magnetic field, the system processes an auxiliary current originated from the topology of a paired Weyl points, namely, the pure CME current. This topological current can be extracted from measuring the center-of-mass motion of ultracold atoms, which may pave the way to directly and unambiguously observe the CME in experiments.