Related Experiment Video
Updated: Aug 5, 2026
06:42
Generation and Coherent Control of Pulsed Quantum Frequency Combs
Published on: June 8, 2018
Realization of Floquet-Engineered Topological Complex-Energy Band Braids in Single-Photon Interferometry
Rui Tian1, Yuanbang Wei1, Yue Zhang1
1Xi'an Jiaotong University, Ministry of Education Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Shaanxi Province Key Laboratory of Quantum Information and Quantum Optoelectronic Devices, School of Physics, Xi'an 710049, China.
Physical Review Letters
|July 26, 2026
Summary
Floquet engineering enables novel topological classifications by creating complex-energy braiding. This method allows for new ways to understand and manipulate topological states of matter using periodic driving.
Area of Science:
- Topological states of matter
- Non-Hermitian physics
- Quantum dynamics
Background:
- Floquet engineering uses periodic driving to control quantum systems.
- Conventional topological classifications are limited to static systems.
- Non-Hermitian band topology is an emerging field.
Purpose of the Study:
- To theoretically predict and experimentally observe fast-driving-tuned topological braiding.
- To develop a new topological classification beyond conventional non-Hermitian band topology.
- To establish Floquet engineering as a general principle for knot topology studies.
Main Methods:
- Theoretical elucidation using the Floquet theorem.
- Experimental realization using a single-photon interferometric network.
- Analysis of eigenspectrum knots and eigenvector loop crossings on the Bloch sphere.
Main Results:
- Observation of topologically distinct complex-energy braiding.
- Demonstration of a new topological classification based on braiding.
- Experimental identification of phase transitions by counting exceptional points.
Conclusions:
- Floquet engineering provides a powerful route to explore exotic nonequilibrium topological phenomena.
- The observed braiding enables a novel topological classification applicable to complex-energy systems.
- Knot topology in Floquet systems can be studied using this general engineering scheme.
Related Concept Videos
02:18Interference and Diffraction
Interference is a characteristic phenomenon exhibited by waves. When two electromagnetic waves interact with their peaks and troughs coinciding, a resulting wave with enhanced amplitude is produced. This is known as constructive interference. In this case, the two waves interacting are in phase with each other.
01:01Energy Bands in Solids
Isolated atoms have discrete energy levels that are well described by the Bohr model. And, it quantifies the energy of an electron in a hydrogen atom as En. Higher quantum numbers 'n' yield less negative, closer electron energy levels.
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states that no two...
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states that no two...
01:12Fermi Level Dynamics
The vacuum level denotes the energy threshold required for an electron to escape from a material surface. It is usually positioned above the conduction band of a semiconductor and acts as a benchmark for comparing electron energies within various materials.
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
01:29Atomic Fluorescence Spectroscopy
Atomic fluorescence spectroscopy (AFS) is an analytical technique that involves the electronic transitions of atoms in a flame, furnace, or plasma being excited by electromagnetic (EM) radiation. When these atoms absorb energy, they become excited and subsequently release energy as they return to their original state. This emitted light, or "fluorescence," is observed at a right angle to the incident beam. Both absorption and emission processes transpire at distinct wavelengths, which are...
01:16UV–Vis Spectroscopy: Molecular Electronic Transitions
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this process,...
01:30Atomic Emission Spectroscopy: Interference
In atomic emission spectroscopy (AES), high-temperature atomizers excite a broad range of elements and molecules that generate complex emissions from sources such as oxides, hydroxides, and flame combustion products in the flame or plasma. Several strategies can be employed to minimize spectral interferences caused by overlapping emission lines or bands. These include increasing instrument resolution, choosing alternative emission lines, optimally placing the detector in low-background regions,...