A postdoctoral position is open at Laboratoire Kastler Brossel to work on the implementation of continuous-variable quantum complex networks.

The project aims at the experimental implementation of large and complex optical networks based on continuous-variable Gaussian correlations [1,2] and non-Gaussian operations [3,4]. The ultimate aims are the exploration of fundamental open questions in such large structures and/or their exploitation in optimized quantum information tasks. The post-doc will work on/supervise one of two cutting-edge setups at near infrared and telecom wavelengths where we recently demonstrated, for the first time, simultaneous multiplexing in time and frequency. This enable three-dimensional structures that are required to build a scalable quantum computer [5]. Protocols than can be addressed: quantum simulation [6], quantum reservoir computing [7], multiparty quantum communication [8] in complex networks [9,10].

The multimode quantum optics group at LKB carried out leading research in experimental generation of cluster states,i.e. large entangled networks useful in quantum information protocol on a large scale. The group has a strong experimental focus, but is also engaged in purely theoretical activities developing quantum optics in the continuous variable framework.

In a nutshell

Why to apply:

-If you are passionate about quantum science, its fundamental aspect and/or real-world applications
-To join an international team of experts in Continuous Variable quantum information spanning both theory and experiments.
– To be part of a group that’s at the heart of national and international research networks, amplifying your impact and collaboration.
Our specific view:
– Continuous variables are exploited to build deterministic and complex quantum networks [2, 9,10]
-We merge pulse-by-pulse temporal and multimode spectral encoding of femtosecond light sources in non-linear processes in waveguides [1,2]
-Measurement-based Gaussian and non-Gaussian operations [3,4] are used to shape quantum resources and perform protocols [6,7,8].

[1] V. Roman-Rodriguez, D. Fainsin, G. L Zanin, N. Treps, E. Diamanti, V. Parigi Spectrally multimode squeezed states generation at telecom wavelengths, arXiv:2306.07267 (2023)

[2] T. Kouadou, F. Sansavini, M. Ansquer, J. Henaff, N. Treps, V. Parigi, Spectrally shaped and pulse-by-pulse multiplexed multimode squeezed states of light, APL Photonics 8, 086113 (2023)
[3] Ra, Y.-S., Dufour, A., Walschaers, M., Jacquard, C., Michel, T., Fabre, C., and Treps, N., Non-Gaussian quantum states of a multimode light field, Nat. Phys. 16, 144–147 (2020)
[4] G. Roeland, S.  Kaali, Vi. Roman Rodriguez, N. Treps, V. Parigi  Mode-selective single-photon addition to a multimode quantum field New J. Phys. 24 043031 (2022)
[5] J. E.,  Bourassa,  et al. Quantum 5, 392 (2021).
[6] P. Renault, J.  Nokkala, G. Roeland, N. Joly, R.  Zambrini, S. Maniscalco, J.  Piilo, N. Treps, V. Parigi Experimental optical simulator of reconfigurable and complex quantum environment arXiv:2302.12674 (2023) accepted in PRX Quantum
[7] J. Nokkala, R. Martínez-Peña, G. L. Giorgi, V. Parigi, M. C Soriano, R. Zambrini, Gaussian states of continuous-variable quantum systems provide universal and versatile reservoir computing, Communications Physics volume 4, Article number: 53 (2021)
[8] O.  Kovalenko, Y.-S. Ra,  Y Cai,  V. C. Usenko ,  C.  Fabre  N. Treps, and R. Filip, Frequency-multiplexed entanglement for continuous-variable quantum key distribution  Photonics Research Vol. 9, pp. 2351-2359 (2021)
[9] M.  Walschaers, N. Treps, B. Sundar, L D Carr, V. Parigi Emergent complex quantum networks in continuous-variables non-Gaussian states Quantum Sci. Technol. 8 035009 (2023)
[10] F. Centrone, F. Grosshans, and V.Parigi Cost and routing of continuous variable quantum networks arXiv:2108.08176



As a whole, the group has a tradition of working together with a diverse range of people from varied backgrounds. This diversity often leads to fruitful scientific input from different points of view, and it allows the group to explore new avenues. Furthermore, the moderate size of our group gives PhD students and postdocs the opportunity to discuss with PIs on a daily basis. This gives rise to a dynamical atmosphere with a lot of space for discussion.Your work fits in the ERC project COCQOoN, and can include the supervision of PhD students. The group is part of several other large research projects, among the most recent:  the national acceleration strategy PEPR OQULUS, EIC Pathfinder VeriQub (European Innovation Council), EIC Pathfinder PANDA (European Innovation Council).  This provides support to enlarge your scientific network and establish new international collaborations.

Laboratoire Kastler Brossel is one of the main worldwide leaders in the field of fundamental physics of quantum systems, covering a number of subjects spanning from fundamental tests of quantum theory to applications. It has an internationally recognized expertise throughout its 65 years history, including three Nobel Prize winners. The multimode quantum optics team explore both fundamental science and applications in CV quantum information. Based in Sorbonne Université in the Pierre and Marie Curie Campus in the center of Paris, it is part of the Quantum Information Center (QICS) in Sorbonne, hosting both quantum physicists and computer scientists. It is also part of the Paris Centre for Quantum Technologies (PCQT), a research, training and innovation network involving 22 research laboratories in Paris Region, 35 start-ups and larger industry groups.

The multimode quantum optics team has experience in technological transfer and collaboration with industrial partner, ongoing collaborations and projects involve Cailabs, Thales and PASQAL. Moreover, we are engaged in mentoring postdoctoral researchers in their actual and future career, both as independent academics or actors in the private sector.


Practical information

Candidates must hold an internationally recognized PhD in a field related to experimental quantum physics.

A good background and past research track record in experimental optics, and quantum physics is required.
Application procedure: Inquiries and applications should be sent by email to Valentina Parigi (valentina.parigi@lkb.upmc.fr). Applications should include a detailed CV and two names of potential referees
Salary: Monthly net salary (after-tax) between 2200€ and 2900€, depending on experience
Application deadline:  Preferentially apply before October 20th
Starting date: flexible
Duration: up to 2 years (with possible renewal of 1 year)