Related Experiment Video
Updated: Jul 10, 2026
07:33
Quantifying Mixing using Magnetic Resonance Imaging
Published on: January 25, 2012
Pairing without superfluidity: the ground state of an imbalanced Fermi mixture
C H Schunck1, Y Shin, A Schirotzek
1Department of Physics, MIT-Harvard Center for Ultracold Atoms, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. chs@mit.edu
Science (New York, N.Y.)
|May 15, 2007
Summary
Strongly interacting Fermi gases with imbalanced spin populations show full pairing of minority atoms. Mismatched Fermi surfaces prevent superfluidity, creating unpaired fermion pairs even at low temperatures.
Area of Science:
- Atomic, Molecular & Optical Physics
- Condensed Matter Physics
- Quantum Gases
Background:
- Understanding fermion pairing is crucial for quantum many-body physics.
- Superfluidity in Fermi gases is sensitive to spin polarization and interactions.
Purpose of the Study:
- Investigate pairing phenomena in strongly interacting Fermi gases.
- Examine the role of spin imbalance and Fermi surface mismatch on superfluidity.
Main Methods:
- Radio-frequency spectroscopy was employed.
- Studied a strongly interacting Fermi gas with imbalanced spin populations.
Main Results:
- At high spin imbalances, superfluidity was absent even at zero temperature.
- Full pairing of minority atoms was observed in the normal phase.
- Mismatched Fermi surfaces did not inhibit pairing itself.
Conclusions:
- Mismatched Fermi surfaces can quench superfluidity without preventing pairing.
- Demonstrated a system of fermion pairs that do not condense at low temperatures.
Related Concept Videos
02:20Dynamic Equilibrium
A reversible chemical reaction represents a chemical process that proceeds in both forward (left to right) and reverse (right to left) directions. When the rates of the forward and reverse reactions are equal, the concentrations of the reactant and product species remain constant over time and the system is at equilibrium. A special double arrow is used to emphasize the reversible nature of the reaction. The relative concentrations of reactants and products in equilibrium systems vary greatly;...
01:05Static Equilibrium - I
A rigid body is said to be in dynamic equilibrium when both its linear and angular acceleration are zero, relative to an inertial frame of reference. This means that a body in equilibrium can be moving, but only when its linear and angular velocities are constant. A rigid body is said to be in static equilibrium when it is at rest in the selected frame of reference. The distinction between static equilibrium (e.g., a state of rest) and dynamic equilibrium (e.g, a state of uniform motion) is...
01:04Oscillations about an Equilibrium Position
Stability is an important concept in oscillation. If an equilibrium point is stable, a slight disturbance of an object that is initially at the stable equilibrium point will cause the object to oscillate around that point. For an unstable equilibrium point, if the object is disturbed slightly, it will not return to the equilibrium point. There are three conditions for equilibrium points—stable, unstable, and half-stable. A half-stable equilibrium point is also unstable, but is named so because...
01:23Equilibrium Conditions for a Particle
When an object is in equilibrium, it is either at rest or moving with a constant velocity. There are two types of equilibrium: static and dynamic. Static equilibrium occurs when an object is at rest, while dynamic equilibrium occurs when an object is moving with a constant velocity. In both cases, there must be a balance of forces acting on the object.
To understand the concept of equilibrium, let us first consider the forces acting on an object. When different forces act on an object, they can...
To understand the concept of equilibrium, let us first consider the forces acting on an object. When different forces act on an object, they can...
01:23Stability of Equilibrium Configuration
Understanding the stability of equilibrium configurations is a fundamental part of mechanical engineering. In any system, there are three distinct types of equilibrium: stable, neutral, and unstable.
A stable equilibrium occurs when a system tends to return to its original position when given a small displacement, and the potential energy is at its minimum. An example of a stable equilibrium is when a cantilever beam is fixed at one end and a weight is attached to the other end. If the weight...
A stable equilibrium occurs when a system tends to return to its original position when given a small displacement, and the potential energy is at its minimum. An example of a stable equilibrium is when a cantilever beam is fixed at one end and a weight is attached to the other end. If the weight...
01:28The Thermodynamics of Mixing
Mixing is a fascinating phenomenon in thermodynamics, particularly when considering the Gibbs energy of a mixture at constant temperature and pressure. This energy, denoted as G, tends to decrease during spontaneous mixing processes, offering insights into the composition changes that occur.Imagine two ideal gases, initially separated in different containers, with amounts nA and nB, respectively, both at a temperature T and pressure p. The chemical potentials of these gases have their 'pure'...