Quantum Light

MIRO is devoted to the theoretical and experimental study of quantum optics, and its role in realizing quantum information protocols and fundamental characteristics of quantum physics. Quantum information is the study of the encoding, transmission, and processing of information under the laws of quantum mechanics.  

Light can be made to possess certain properties, such as quantum entanglement and squeezing, which makes it inherently non-classical. These properties are directly responsible for the success of many quantum information protocols, such as quantum teleportation and quantum key distribution (QKD), which are tasks in which a quantum approach can outperform a classical one. 

Over the last five years, we have built experimental testbeds that are capable of generating, managing, and measuring quantum states of light. One method is to produce a single photon, that is, a quantum of light, which has a transverse-momentum degree of freedom that can be discretized to form a d-dimensional system.  This approach has allowed us to perform novel experiments and make important contributions to device-independent certification of quantum properties and randomness amplification, quantum state estimation, and tomography.    

The most modern version of our devices uses multi-core optical fibers to transmit information.  Moreover, we manipulate and measure high-dimensional quantum states using novel multi-core fiber beam splitters.  Some of our research highlights include the realization of the indefinite causal order of quantum gates, generalized measurements in higher dimensions, high-dimensional entangled states, and high-quality polarization-entangled photon pairs, which can be used for more restrictive self-testing protocols.   Most recently, a multi-core fiber link was recently installed over a total distance of about 800m, joining four laboratories.  Currently, we are expanding our capabilities with a focus towards multi-photon states (more than two) and squeezed states.   

Our theoretical research in quantum light includes the development of methods to characterize quantum states of light, in particular those of higher dimension.