Limit of spin squeezing in finite-temperature Bose-Einstein condensates

Area of Science:

• Quantum physics
• Atomic physics
• Condensed matter physics

Background:

• Bose-Einstein condensates (BECs) are quantum states of matter.
• Spin squeezing is a quantum metrology technique to reduce measurement uncertainty.
• Controlling quantum states in BECs is crucial for precision measurements.

Purpose of the Study:

• To determine the theoretical limit of spin squeezing in Bose-Einstein condensates at finite temperatures.
• To investigate the influence of atom number and system parameters on spin squeezing.
• To establish bounds for spin squeezing in spatially homogeneous BECs.

Main Methods:

• Theoretical calculation of the spin squeezing parameter.
• Analysis of Bose-Einstein condensates at finite temperatures.
• Asymptotic analysis for large atom numbers (N→∞) at fixed density and interaction strength.

Main Results:

• The maximum achievable spin squeezing in BECs at finite temperatures has a finite upper limit as atom number increases.
• For spatially homogeneous systems, this limit is bounded by the initial fraction of non-condensed atoms.
• The interaction strength and density do not overcome this fundamental limit.

Conclusions:

• Finite temperature and the initial noncondensed fraction fundamentally limit spin squeezing in BECs.
• The theoretical limit provides a benchmark for experimental efforts in quantum metrology with BECs.
• Understanding these limitations is key for developing more precise quantum sensors.