Related Experiment Video
Updated: Jul 7, 2026
08:04
Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
Macroscopic atom-molecule dark state and its collective excitations in fermionic systems
Andrew Robertson1, Lei Jiang, Han Pu
1Department of Physics and Astronomy, Rowan University, Glassboro, New Jersey 08028-1700, USA.
Physical Review Letters
|February 1, 2008
Summary
A novel atom-molecule dark state in fermionic systems enables coherent oscillations between molecular Bose-Einstein condensates and atomic paired states, revealing insights into collective excitations.
Area of Science:
- Quantum physics
- Ultracold atomic gases
- Condensed matter physics
Background:
- Fermionic systems exhibit complex quantum phenomena.
- Bose-Einstein condensates and BCS paired states are key areas of study.
Purpose of the Study:
- To demonstrate the existence of a macroscopic atom-molecule dark state in fermionic systems.
- To explore coherent oscillations between molecular and atomic states.
- To interpret oscillation frequencies via collective excitations.
Main Methods:
- Utilizing tunable external laser fields.
- Investigating coherent superposition states.
- Analyzing oscillation frequencies.
Main Results:
- Established the existence of a robust macroscopic atom-molecule dark state.
- Demonstrated coherent oscillations between ground molecules and atom pairs.
- Interpreted oscillation frequencies in terms of dark state collective excitations.
Conclusions:
- Atom-molecule dark states are a viable phenomenon in fermionic systems.
- Tunable laser fields are effective for manipulating these states.
- The study provides a framework for understanding collective excitations in such systems.
Related Concept Videos
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...
02:45The Quantum-Mechanical Model of an Atom
Shortly after de Broglie published his ideas that the electron in a hydrogen atom could be better thought of as being a circular standing wave instead of a particle moving in quantized circular orbits, Erwin Schrödinger extended de Broglie’s work by deriving what is now known as the Schrödinger equation. When Schrödinger applied his equation to hydrogen-like atoms, he was able to reproduce Bohr’s expression for the energy and, thus, the Rydberg formula governing hydrogen spectra. Schrödinger...
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...
02:28Electronic Structure of Atoms
An atom comprises protons and neutrons, which are contained inside the dense, central core called the nucleus, with electrons present around the nucleus. Taking into account the wave–particle duality of electrons and the uncertainty in position around the nucleus, quantum mechanics provides a more accurate model for the atomic structure. It describes atomic orbitals as the regions around the nucleus where electrons of discrete energy exist, characterized by four quantum numbers: n, l, ml, and...
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...
01:14Atomic Nuclei: Nuclear Spin State Population Distribution
Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.