Breakthrough in Quantum Transport: RRI Researchers Unlock New Insights Using Ultra-Cold Atoms

The findings, published in Optics Letters, mark a crucial step in advancing the understanding of quantum systems and their response to tunable interactions.

Researchers at the Raman Research Institute (RRI), funded by the Department of Science and Technology (DST), Government of India, have made significant strides in understanding quantum transport properties by observing the behavior of ultra-cold potassium atoms under sudden exposure to laser pulses. This pioneering study offers promising advancements for the development of smart, high-conductivity materials and next-generation battery components.

Ultra-cold atoms, cooled to temperatures near absolute zero, provide an ideal platform for precision measurements of quantum effects such as tunneling and quantized conductance, both crucial for nanoscale electronics. The study focused on quantum charge transport, where the flow of charge and energy is governed by quantum statistical principles rather than classical electron dynamics.

The RRI team, led by Dr. Saptarishi Chaudhuri from the Quantum Mixtures (QuMIX) lab, conducted experiments on neutral potassium atoms trapped in a Magneto-Optical Trap (MOT). The MOT, which employs laser cooling and magnetic fields, confined the atoms to micro-kelvin temperatures. Two experimental settings were tested:

1. Single Laser Beam: A driving laser beam displaced the trapped atoms, inducing oscillations resembling a damped harmonic oscillator.
2. Dual Laser Beams with Photoassociation (PA): An additional laser beam near a photoassociation resonance significantly altered the atoms' interatomic interactions, resulting in a transition from overdamped to underdamped oscillations.

Photoassociation, a process where atoms briefly form molecules, altered the interaction strength and transport properties. Lead author and PhD student Anirban Misra described the collective oscillations observed during sudden atomic displacement as "both surprising and counter-intuitive." This behavior revealed how laser tuning can dramatically influence quantum dynamics.

A theoretical model developed by collaborating authors Supurna Sinha and Urbashi Satpathy provided critical insights into how PA resonance enhances interatomic interactions, enabling the detection of molecular resonances. By adjusting control parameters such as laser power and magnetic field gradients, the team demonstrated the ability to precisely manipulate quantum transport dynamics.

The findings, published in Optics Letters, mark a crucial step in advancing the understanding of quantum systems and their response to tunable interactions. The RRI researchers emphasize that further exploration of these dynamics could revolutionize the design of efficient, customizable, and high-conductivity materials for advanced technological applications, including next-generation batteries and quantum computing components.