Master 2 internship – Synthetic Photonic Matter with
phase-transition engineering in a Quantum Fluid of Light

Institution: Sorbonne University – Ecole Normale Sup´erieure – CNRS – Laboratoire Kastler Brossel
Team: Quantum Fluids of Light team – Alberto Bramati, Quentin Glorieux, Hanna Le Jeannic
Location: Jussieu campus. Paris, France
Duration: 3-6 months – followed by a ERC-funded PhD
Websites: and

Quantum fluids of light
Photons are great carriers of information but they usually don’t interact with one another. Atoms in-
teract but are hard to manipulate and do not benefit from the toolbox of quantum optics for detecting
quantum fluctuations and entanglement. Many approaches have been proposed to marry these two
systems for quantum simulation of condensed matter with strongly interacting photons,
but to date, the realization of large-scale synthetic materials made of optical photons is still missing.
Our team targets this exciting goal, namely the creation of Synthetic Photonic Matter.
This ambitious goal relies on our original approach of engineering a quantum phase transition in a
quantum fluid of light. Indeed, it has been realized that, under suitable circumstances, photons can
acquire an effective mass and will behave as a quantum fluid of light with photon-photon interactions.
Striking experimental demonstrations of superfluidity and other quantum hydrodynamics effects such as
quantized vortices and solitons have been performed using fluids of light. The current situation is then;
we have a superfluid of light (left part of the image below) and we want to create Syntehtic Photonic
Matter (right part of the image).

Internship Description
Building on these experiments done by the LKB group, we propose to use a platform based on atomic
cloud of Rubidium to study quantum fluids of light in a new regime. Specifically, we will investigate
the superfluid to Mott insulator transition for light propagating in a dense cold atomic
cloud. In this regime, photons will follow an evolution similar to ultracold atomic quantum gases and
our original hypothesis is that a fluid of light should undergo the same phase transition, driven by
quantum fluctuations, as quantum gases do, and therefore a many-body state of light will emerge from
this transition.

Key Responsibilities
As a member of the quantum fluids of light team you will be in charge to
• Design and build a novel cold-atoms setup to explore the physics of fluids of light in the strong
interaction regime.
• Collaborate with other team members to conduct experiments and data analysis on already working
setups in hot atomic vapors.

Impact of the project
At the fundamental level, a Mott insulator state of light allows for exploring truly quantum effects
such as the emergence of analogue of phase transition in non-equilibrium systems, the presence of quan-
tum depletion and pre-thermal states and the entanglement dynamics in many-body systems. On the
applied side, a photonic Mott insulator is a giant source of single photons (or any Fock state)
with potentially several hundreds of lattice sites delivering tunable photon number-states in parallel. It
will be a game changer for scalability issues in photonics quantum technologies.

How to Apply – Contact Us
We are offering an internship opportunity (followed by an ERC-funded PhD) to expand the
capabilities of this platform to a new level by increasing by many orders of magnitude the effective
photon-photon interactions and enter the strong interaction regime.
For inquiries or more information about this internship or to apply for this internship, please contact us
directly at

Quantum fluids of light group at LKB
We are a group of friendly and welcoming scientists and we aim to create an inclusive and supportive
research environment. We strongly believe in the value of diversity and inclusion in the field of
quantum physics and we encourage women and/or individuals from underrepresented minority
groups to apply for this internship.