Related Experiment Video
Updated: Jul 11, 2026
10:35
Using Microwave and Macroscopic Samples of Dielectric Solids to Study the Photonic Properties of Disordered Photonic Bandgap Materials
Published on: September 26, 2014
Quantum glass phases in the disordered Bose-Hubbard model
Pinaki Sengupta1, Stephan Haas
1T-CNLS and NHMFL, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Physical Review Letters
|October 13, 2007
Summary
Quantum Monte Carlo simulations reveal new quantum glass phases in the Bose-Hubbard model. A novel Mott glass phase, incompressible yet gapless, emerges at the interface of Mott insulating and superfluid states.
Area of Science:
- Condensed matter physics
- Quantum many-body systems
- Disordered quantum systems
Background:
- The Bose-Hubbard model describes interacting bosons on a lattice.
- Understanding the effects of disorder is crucial for realistic quantum systems.
- Clean Bose-Hubbard systems exhibit Mott insulating and superfluid phases.
Purpose of the Study:
- To determine the phase diagram of the Bose-Hubbard model with off-diagonal disorder.
- To identify and characterize novel quantum glass phases.
- To investigate the interplay between disorder and quantum phase transitions.
Main Methods:
- Quantum Monte Carlo simulations were employed.
- The study analyzed global observables like compressibility and superfluid stiffness.
- Local observables such as compressibility and momentum distribution were examined.
Main Results:
- A sequence of quantum glass phases was identified at the interface of Mott insulating and superfluid phases.
- The standard Bose glass phase was observed.
- A novel Mott glass regime, characterized by incompressibility and gaplessness, was discovered.
- Numerical evidence supporting these findings was provided through various observables.
Conclusions:
- Off-diagonal disorder in the Bose-Hubbard model leads to complex quantum glass phases.
- The newly identified Mott glass regime presents unique properties of being incompressible yet gapless.
- The findings offer insights into the behavior of disordered quantum systems and their phase transitions.
Related Concept Videos
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...
02:18The Bohr Model
Following the work of Ernest Rutherford and his colleagues in the early twentieth century, the picture of atoms consisting of tiny dense nuclei surrounded by lighter and even tinier electrons continually moving about the nucleus was well established. This picture was called the planetary model since it pictured the atom as a miniature “solar system” with the electrons orbiting the nucleus like planets orbiting the sun. The simplest atom is hydrogen, consisting of a single proton as the nucleus...
02:39Phase Transitions: Vaporization and Condensation
The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. Vaporization occurs when the thermal motion of the molecules overcome the intermolecular forces, and the molecules (at the surface) escape into the gaseous state. When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase molecules...
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...
01:21Phase Transitions
A phase transition is the process in which a substance changes from one state of matter to another, like from a solid to a liquid, liquid to gas, or vice versa, at a specific temperature and under given pressure conditions. This change is spontaneous and is affected by alterations in temperature and pressure. These parameters impact the strength of the forces between molecules (intermolecular forces) in the substance.During a phase transition, both the initial and final phases of the substance...
02:31Phase Transitions
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to occupy...