Scientists are trying to generate sources for single and entangled Phonons (or quantised sound waves) that can have applications in thermally insulating buildings, reducing environmental noise, transforming waste heat into electricity, and developing earthquake protection.

Phonons are collective excitations in lattices or the periodic, elastic arrangement of atoms or molecules. Elastic waves propagate inside materials mediated by lattice vibrations quantized in the form of phonons (in analogy to Photons that similarly quantify Light). As vibration is a universal phenomenon underlying many physical processes, Phononic systems offer the potential to revolutionize sensing and computing, allowing for recycling of waste heat and energy. Quantum Phononics will also enable low-noise imaging at very high frequencies, harnessing phenomena such as entanglement and squeezed states, yielding extremely fine precision in non-invasive materials diagnostics.

Prof. Prabhu Rajagopal from IIT Madras, a recipient of this year’s SwarnaJayanti fellowship instituted by the Department of Science & Technology, Government of India, proposes to develop novel concepts for achieving sources for single and entangled phonons. He has proposed a novel airtight nanoscale coupled mechanical oscillator device as a source for single Phonons, with near-micrometer dimensions and operation at higher milli-Kelvin temperatures, which will be further studied and tested out during this project. Moreover, completely new approaches to achieving entangled states through the use of metamaterials and novel Cooper-pair like states will also be studied.

According to Prof. Rajagopal, sound-based analogues of currently prevalent technologies are increasingly attractive as they can access a wide range of phenomena and also harness waste heat more naturally. The prestigious Swarnajayanti Fellowship award will make practical Quantum Phononics possible, with disruptive benefits for industrial and biomedical diagnostics, offering a safe alternative to radiation-prone electromagnetic techniques.

This work can help connect Indian research to the global effort towards Quantum Computers through the realization of Phonon sources, which are an essential ingredient in Phononic Circuits.

For more details, contact Prof. Prabhu Rajagopal (prajagopal[at]iitm[dot]ac[dot]in).