Welcome !

This is the website of the Laboratory of Nonlinear Photonics and Theoretical Physics at the Department of Physics of the University Sapienza and the Institute for Complex Systems of the National Research Council. Our program is applying paradigms from the science of complex systems to light propagation, and investigating the development of complexity and self-organization in nonlinear waves. We want to test and deepen ideas of fundamental physics by using optics and photonics, and developing experiments, high performance computing approaches, and theory.

Please visit our research pages or our Blog.







Press Release Time Travel IS NOT possible

Our paper on the Glauber oscillator and Time Travel had a relevant press release ...







Other press release is found in the links below






Ritorno al futuro? Rassegniamoci: i viaggi nel tempo sono impossibili ­ Repubblica.it
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Last Updated (Monday, 30 November 2015 13:13)


Glauber oscillator and time travel

The standard quantum mechanics does not forbid time-travel. However, some alternative formulations (based on the so called "rigged Hilbert space") include irreversibility as a fundamental principle: a quantum particle that decays cannot travel back in time.

There are not direct evidences of the irreversibility of decay processes, but the new quantum mechanics predicts that the decay rates are quantized.

If one observes the quantization of the decay rates, one can claim to have provided experimental support to the irreversible formulation of quantum mechanics.

In simple terms, one can claim that time-travel is not possible at the quantum level (...and also at the classical level).

Silvia Gentilini, Maria Chiara Braidotti, Giulia Marcucci, Eugenio Del Re, and Claudio Conti simulated in the laboratory one of the simplest models of the irreversible quantum mechanics, that follows an original proposal of Glauber. A laser beam emulates a quantum particle in a reversed harmonic oscillator, as a result the first experimental evidence of the quantization of decay time is reported in a paper published in Scientific Reports.


Last Updated (Saturday, 07 November 2015 20:41)


How much can you twist a ultrashort pulse?

If you have a ultrashort pulse, and you want to add angular momentum, you have limitations.

This is what Andrea Ornigotti, Claudio Conti, and Alexander Szameit, discovered and published in the Physical Review Letters. An extended and generalized analysis can be found in Physical Review A.

Angular momentum of light is nowadays largely studied because you can add information to a optical beam by twisting it, or you can rotate objects by lasers with angular momentum. But if you want to transmit information, the best thing to do is using light pulses and adding to any pulse a certain amount of orbital angular momentum (OAM).  For example, by using m levels of OAM, any single pulse can encode m symbols (2 symbols correspond to one bit). The shortest the pulse you use, the higher the number of symbols you can transmit in a second (the transmission rate). This approach can be used for new classical and quantum high-bit rate transmission systems in free space or in fiber. 

But Ornigotti and others find out that the number of OAM bits you can store in a single pulse is actually limited by the duration of the pulse and by its carrier frequency.

The following picture shows the link between OAM units m and the number of optical cycles in the pulse, these two quantized observables are actually strictly related.



These findings have important outcomes in the modern multilevel transmission systems, but also reveal a novel form of spatio-temporal coupling. The latter may lead to new kinds of entanglement, which may trigger applications in Quantum Optics.




Last Updated (Sunday, 04 October 2015 12:18)


The John Templeton Foundation !

Great news ! 

The John Templeton Foundation is funding us!

Out project "Generalized Uncertainty Principle and the Photon" has been funded for searching the links between quantum gravity and photonics.


Last Updated (Sunday, 30 August 2015 10:02)