Hot Single Photons for Quantum Communications, QuanTour ft. Carlos Antós Solanas

Hot Single Photons for Quantum Communications, QuanTour ft. Carlos Antós Solanas

In Other Words

An experiment born of a mistake at the end of his postdoc with Pascale Senellart: exciting a semiconductor quantum dot with two close pulses to create a vacuum-and-single-photon entangled |00>+|11> state; a year of pandemic-era analysis confirmed it, and with more pulses the emitted light state follows the Fibonacci sequence and golden ratio.

Key Takeaways

• Tenure-track researcher at the Autonomous University of Madrid working on ‘hot’ (room-temperature) single photons from defects in hexagonal boron nitride, alongside continued work on semiconductor quantum dots.
• Cold vs hot single photons: cooling quiets crystal vibrations to give identical, interference-ready photons; room-temperature photons carry more noise but need no cryostat, so they suit drones, cars, satellites.
• hBN is currently the front-runner room-temperature single-photon material; defects can be placed deterministically by electron irradiation of flakes.
• Advice he passes on: change material platform (a calculated risk) between PhD and postdoc, and build broad international experience and networks before setting up a group.
• Leads a QuantERA project (COMPHORT, with Tobias Heindel) targeting 700 m free-space quantum key distribution with hot single photons by 2027; wishes for less bureaucracy, more funding, and a good coffee machine.