Qauntum Coherence & Entanglement

We have made a photonic Maxwell’s demon more efficient by using correlated photons.

(c) Rozema/Antesberger

Many quantum predictions are difficult to build an intuition for.  While a quantum particle can be in a superposition of different states, classical everyday objects appear in a definite state.  This leads to many surprising quantum effects, such as entanglement, wave-particle duality and interference.  We are interested in designing table-top experiments to demonstrate and make use of such effects.  Our work along these lines includes testing alternative versions of quantum theory, finding new ways to encode and communicate with quantum systems, and, more recently, attempting to find ways to study quantum thermodynamics with photons.

In practice, much of our recent experimental work has begun to encode information in the time degree of freedom of photons.  This means we are using active optical elements to manipulate photons on the fly.  This gives the opportunity to talk to photons in new ways, and it turns out some of our techniques could even lead to advantages and overlap with other research pillars, such as secure communication.

Publications (selected)

Distribution of Time-Bin Entangled Photons through a 7.7 km Hollow-Core Fiber
M. Antesberger, C. M. D. Richter, F. Poletti, R. Slavik, P. Petropolous, H. Hubel, A. Trenti, P. Walther, L.A. Rozema
Optica Quantum (2024).

Experimental Higher-Order Interference in a Nonlinear Triple Slit
P. Namdar, P. Jenke, I. Alonso Calafell, A. Trenti, M. Radonjic, B. Dakic, P. Walther, L. A. Rozema
Physical Review A 107, 032211 (2023).

Inferring Work by Quantum Superposing Forward and Time-Reversal Evolutions
G. Rubino, G. Manzano, L. A. Rozema, P. Walther, J. M.R. Parrondo, C. Brukner
Physical Review Research 4, 013208, (2022)

Enhanced Photonic Maxwell's Demon with Correlated Baths
G.L. Zanin, M. Anteberger, M.J. Jacquet, P.H.S. Ribeiro, L.A. Rozema, P. Walther
Quantum 6, 810 (2022).

Fiber-compatible photonic feed-forward with 99% fidelity
G. L. Zanin, M. J. Jacquet, M. Spagnolo, P. Schiansky, I. A. Calafell, L.A. Rozema, P. Walther
Optics Express 29, 3425-3437 (2021).

Experimental Two‐Way Communication with One Photon
F. Massa, A. Moqanaki, Ä. Baumeler, F. Del Santo, J. A. Kettlewell, B. Dakić, P. Walther
Advanced Quantum Technologies 2, 1900050 (2019).

Trace-free counterfactual communication with a nanophotonic processor
I. Alonso Calafell, T. Strömberg, D. R. M. Arvidsson-Shukur, L. A. Rozema, V. Saggio, C. Greganti, N. C. Harris, M. Prabhu, J. Carolan, M. Hochberg, T. Baehr-Jones, D. Englund, C. H. W. Barnes, P. Walther
npj Quantum Information 5, 61 (2019).

Single-photon test of hyper-complex quantum theories using a metamaterial
L.M. Procopio, L.A. Rozema, Z.J. Wong, D.R. Hamel, K. O’Brien, X. Zhang, B. Dakic, P. Walther,
Nature Communications 8, 15044 (2017).