Spin Entanglement Witness for Quantum Gravity

Area of Science:

• Quantum physics
• Quantum gravity
• Experimental physics

Background:

• Reconciling quantum mechanics and general relativity remains a major challenge.
• Empirical evidence for quantum gravity is lacking, fueling debate on gravity's quantum nature.
• Current experimental proposals struggle to test quantum gravity's coherent behavior.

Purpose of the Study:

• To propose a feasible laboratory experiment to test the quantum nature of gravity.
• To demonstrate that gravitational interactions can mediate quantum entanglement between masses.
• To provide a method for experimentally certifying gravity as a quantum coherent mediator.

Main Methods:

• Utilizing adjacent matter-wave interferometers with micron-sized test masses.
• Analyzing the phase evolution induced by gravitational interaction between masses.
• Designing a protocol for witnessing entanglement via spin correlation measurements.

Main Results:

• Gravitational interaction between two micron-sized masses can induce detectable entanglement.
• Entanglement is achievable even when masses are sufficiently separated to mitigate Casimir-Polder forces.
• The proposed method allows for direct experimental certification of gravity's quantum mediating role.

Conclusions:

• The experiment offers a direct pathway to test the quantum nature of gravity.
• This work provides a concrete experimental blueprint for probing quantum gravity.
• Successful implementation would resolve the debate on gravity as a quantum entity.