Algorithmic cooling of nuclear spins using long-lived singlet order

Area of Science:

• Quantum physics
• Quantum information science
• Nuclear magnetic resonance

Background:

• Algorithmic cooling aims to reduce the temperature of open quantum systems below their environment.
• Nuclear spin systems offer a platform for exploring quantum phenomena and developing quantum technologies.
• The long-lived nuclear singlet state, an antisymmetric quantum superposition, plays a crucial role in quantum information processing.

Purpose of the Study:

• To demonstrate significant cooling of nuclear spin-pair systems using algorithmic cooling.
• To exploit the properties of the long-lived nuclear singlet state for enhanced cooling.
• To convert pumped singlet order into enhanced nuclear magnetization.

Main Methods:

• Utilizing nuclear magnetic resonance (NMR) experiments on a molecular system with coupled 13C nuclei.
• Applying a repeating sequence of cyclic permutations interspersed with relaxation intervals.
• Manipulating the populations of the nuclear spin system through algorithmic cooling protocols.

Main Results:

• Achieved significant cooling of an ensemble of nuclear spin-pair systems.
• Successfully exploited the long-lived nuclear singlet state for cooling.
• Converted singlet order into nuclear magnetization enhanced by 21% beyond thermal equilibrium.

Conclusions:

• Algorithmic cooling is an effective method for reducing the temperature of nuclear spin systems.
• The long-lived nuclear singlet state is a valuable resource for quantum cooling and enhancing nuclear magnetization.
• The demonstrated technique shows potential for applications in quantum sensing and quantum information processing.