Related Experiment Video
Updated: Aug 17, 2025
14:14
Quantification of Strain in a Porcine Model of Skin Expansion Using Multi-View Stereo and Isogeometric Kinematics
Published on: April 16, 2017
11.7K
Transient non-Hermitian skin effect.
Zhongming Gu1, He Gao2, Haoran Xue3
1Institute of Acoustics, School of Physics Science and Engineering, Tongji University, 200092, Shanghai, China.
Nature Communications
|December 12, 2022
Summary
Researchers demonstrate the non-Hermitian skin effect (NHSE) in a passive system without gain media. This transient NHSE utilizes virtual gain, enabling observation of skin mode localization in passive platforms.
Area of Science:
- Condensed matter physics
- Quantum mechanics
- Wave phenomena
Background:
- The non-Hermitian skin effect (NHSE) is a unique phenomenon in non-Hermitian systems, characterized by the accumulation of modes at the boundaries.
- Observing the full evolution of NHSE typically requires gain media, which complicates system design and robustness.
Purpose of the Study:
- To demonstrate the observation of the complete evolution of NHSE in a passive system.
- To investigate the possibility of realizing NHSE without relying on gain media.
Main Methods:
- Utilized a simple lattice model and acoustic ring resonators.
- Employed complex-frequency excitation to induce a virtual gain effect.
- Experimentally demonstrated NHSE in a totally passive system during a quasi-stationary stage.
Main Results:
- Successfully observed transient non-Hermitian skin effect (NHSE) in a passive system.
- Showcased the persistence of exact NHSE during a quasi-stationary stage without gain.
- Confirmed that the localization character of skin modes can be witnessed and exploited despite general energy decay.
Conclusions:
- Excitation plays a crucial role in realizing NHSE.
- Passive systems can fully support the observation of NHSE's complete evolution.
- Findings open avenues for studying non-Hermitian physics using diverse passive platforms.
Related Concept Videos
01:14Changes in Skin Color: Clinical Perspectives
2.0K
The first thing a clinician sees is the skin, so the examination of the skin should be part of any thorough physical examination. Most skin disorders are relatively benign, but a few, including melanomas, can be fatal if untreated. A couple of the more noticeable disorders, albinism and vitiligo, affect the appearance of the skin and its accessory organs.
Albinism
Albinism is a genetic disorder that affects (completely or partially) the coloring of skin, hair, and eyes. The defect is primarily...
Albinism
Albinism is a genetic disorder that affects (completely or partially) the coloring of skin, hair, and eyes. The defect is primarily...
2.0K
01:24Transient and Steady-state Response
239
In control systems, test signals are essential for evaluating performance under various conditions. The ramp function is effective for systems undergoing gradual changes, while the step function is suitable for assessing systems facing sudden disturbances. For systems subjected to shock inputs, the impulse function is the most appropriate test signal.
These test signals are integral in designing control systems to exhibit two key performance aspects: transient response and steady-state...
These test signals are integral in designing control systems to exhibit two key performance aspects: transient response and steady-state...
239
01:16Electrostatic Boundary Conditions
556
Consider an external electric field propagating through a homogeneous medium. When the electric field crosses the surface boundary of the medium, it undergoes a discontinuity. The electric field can be resolved into normal and tangential components. The amount by which the field changes at any boundary is given by the difference between the field components above and below the surface boundary.
The surface integral of an electric field is given by Gauss's law in integral form and is related to...
The surface integral of an electric field is given by Gauss's law in integral form and is related to...
556
01:19Pigmentation
2.5K
The color of the skin is influenced by a number of pigments, including melanin, carotene, and hemoglobin. Recall that melanin is produced by cells called melanocytes, which are found scattered throughout the stratum basale of the epidermis. The melanin is transferred to the keratinocytes via melanosomes.
Melanin occurs in two primary forms: eumelanin that provides black and brown pigment and pheomelanin that provides red color. Dark-skinned individuals produce more melanin than those with pale...
Melanin occurs in two primary forms: eumelanin that provides black and brown pigment and pheomelanin that provides red color. Dark-skinned individuals produce more melanin than those with pale...
2.5K
01:27Electrostatic Boundary Conditions in Dielectrics
1.3K
When an electric field passes from one homogeneous medium to another, crossing the boundary between the two mediums imparts a discontinuity in the electric field. This results in electrostatic boundary conditions that depend on the type of mediums the field propagates through.
Consider a case where both the mediums across a boundary are two different dielectric materials. Recall that the electric field and electric displacement are proportional and related through the material's...
Consider a case where both the mediums across a boundary are two different dielectric materials. Recall that the electric field and electric displacement are proportional and related through the material's...
1.3K
01:29Potential Due to a Polarized Object
457
A neutral atom consists of a positively charged nucleus surrounded by a negatively charged electron cloud. When placed in an external electric field, the external electric force pulls the electrons and nucleus apart, opposite to the intrinsic attraction between the nucleus and the electrons. The opposing forces balance each other with a slight shift between the center of masses of the nucleus and the electron cloud, resulting in a polarized atom. On the other hand, a few molecules, like water,...
457