Experimentos usando qudits de camino en altas dimensiones para información cuántica = Experiments using high dimensional path qudits for quantum information.

Abstract

ional quantum states is presented. Weak coherent pulses in the single photon level are prepared when a continuous wave 690 nm laser is pulsed with an Acousto Optical Modulator (AOM) and attenuated using neutral filters. The quantum states are encoded in the transverse linear momentum (TLM) of individual photons. The manipulation of TLM is performed by Spatial Light Modulators (SLMs), who display sets of d transmissive apertures (slits) giving the photon d alternative paths to propagate through, addressing the d dimensional state |ψi the user wants to prepare. Two SLMs combined manipulate the real and imaginary part of the coefficients of |ψi, completing the generation stage of the setup. The SLMs are fully automated using Field Programmable Gate Array (FPGA) electronics. Once the state is generated, we can choose a previously calculated projective measurement hφ| to be implemented. This is done preparing a new set of d slits in another pair of SLMs, located in the measurement stage of the setup. Finally, an Avalanche Photo Diode masked with a 10 µm pinhole measures the overlap probability of |hφψi| 2 from the accumulated statistics of the binary APD outcomes. Since the visibility of the output signal of the is around 0.98, a wide variety of quantum tasks can be performed using the presented experimental setup.