Related Experiment Video
Updated: May 22, 2026
06:42
Generation and Coherent Control of Pulsed Quantum Frequency Combs
Published on: June 8, 2018
Localized end states in density modulated quantum wires and rings
Suhas Gangadharaiah1, Luka Trifunovic, Daniel Loss
1Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland.
Physical Review Letters
|May 1, 2012
Summary
We found stable Tamm-Shockley bound states in quantum wires, which can host spin qubits. These states exhibit unique 4π Aharonov-Bohm periodicity, detectable in experiments.
Area of Science:
- Condensed Matter Physics
- Quantum Mechanics
- Materials Science
Background:
- Charge-density wave (CDW) gaps are crucial for understanding electronic properties in low-dimensional systems.
- Periodic modulation of chemical potential can induce CDW gaps in quantum wires and rings.
- Tamm-Shockley bound states are localized electronic states at the edges of materials.
Purpose of the Study:
- Investigate the stability and properties of Tamm-Shockley bound states in finite quantum wires with CDW gaps.
- Explore the potential of these bound states for applications in quantum computing, specifically as spin qubits.
- Identify experimental signatures for detecting these novel electronic states.
Main Methods:
- Theoretical study of finite quantum wires and rings with CDW gaps.
- Analysis of Tamm-Shockley bound states stability against disorder and interactions.
- Mapping low-energy physics to Jackiw-Rebbi equations for massive Dirac fermions.
- Utilizing a continuum model to incorporate electron-electron interactions.
Main Results:
- Tamm-Shockley bound states are stable against weak disorder and interactions in both discrete and continuum models.
- Electron interactions increase the charge gap and enhance the localization of end states.
- The system can function as a double quantum dot for hosting spin qubits via exchange interactions.
- Predicted unusual 4π Aharonov-Bohm periodicity in spectrum and persistent current.
Conclusions:
- Finite quantum wires with CDW gaps host robust Tamm-Shockley bound states.
- These states offer a promising platform for developing spin qubits in a double quantum dot configuration.
- Experimental detection is feasible through characteristic 4π Aharonov-Bohm oscillations.
Related Concept Videos
01:28Standing Waves in a Cavity
A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by:
02:32The de Broglie Wavelength
In the macroscopic world, objects that are large enough to be seen by the naked eye follow the rules of classical physics. A billiard ball moving on a table will behave like a particle; it will continue traveling in a straight line unless it collides with another ball, or it is acted on by some other force, such as friction. The ball has a well-defined position and velocity or well-defined momentum, p = mv, which is defined by mass m and velocity v at any given moment. This is the typical...
02:42Valence Bond Theory
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
02:35Molecular Orbital Theory I
Overview of Molecular Orbital Theory
01:23Atomic Nuclei: Nuclear Relaxation Processes
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis. This...
01:03Atomic Nuclei: Nuclear Spin State Overview
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of one, the...