Deterministic entanglement generation from driving through quantum phase transitions

Area of Science:

• Quantum physics
• Atomic physics
• Many-body systems

Background:

• Many-body entanglement is crucial for quantum technologies but challenging to create and maintain.
• Nonlinear interactions can generate entanglement but also cause degradation.
• Controlling quantum dynamics is key to harnessing entanglement.

Purpose of the Study:

• To demonstrate near-deterministic generation of a large-scale entangled twin-Fock condensate.
• To leverage quantum phase transitions (QPTs) for robust entanglement creation.
• To quantify the generated entanglement and its potential applications.

Main Methods:

• Driving a rubidium-87 Bose-Einstein condensate through spin mixing.
• Utilizing two consecutive quantum phase transitions (QPTs).
• Directly observing number squeezing and collective spin length.

Main Results:

• Generation of an entangled twin-Fock condensate with approximately 11,000 atoms.
• Observed number squeezing of 10.7 ± 0.6 decibels.
• Measured normalized collective spin length of 0.99 ± 0.01.
• Inferred entanglement-enhanced phase sensitivity beyond the standard quantum limit (~6 dB).
• Determined an entanglement breadth of approximately 910 atoms.

Conclusions:

• Quantum phase transitions provide a powerful tool for generating large-scale, useful entanglement.
• The demonstrated method offers a pathway to overcome entanglement degradation.
• This work advances the creation of entangled states for quantum sensing and computation.