Speaker
Ms
Marie Louise Umuhire
(University of Kwazulu Natal, School of Chemistry and Physics, Westville Campus, Durban, South Africa)
Description
Quantum communication is a means of encoding information in the form of single photons and share that information amongst authorised parties regardless of the presence of an adversary [1, 2]. For free-space communication, the communication is not only threatened by the eavesdropper but also by the atmospheric turbulence since it does have an impact on the information passing through it. Therefore, it is important to study the channel before transferring information through it [1, 2].
Optically atmospheric turbulence is observed as a medium with a refractive index nearly equals to unity which randomly changes over space and time and this causes light to be randomly distorted as it passes through the atmosphere [3]. This means that the radiation passing through the atmosphere might be absorbed, emitted as well as refracted [3]. Optical systems which depends on the propagation of light through the atmosphere must control this phenomenon since it is considered as a quantum channel (free-space) which enables the transfer of quantum information [3].
In this work, we are studying the impact the atmospheric turbulence has on a single photon source by observing how the entangled photons survive through the environment. This is done by verifying the Bell’s inequality and by reconstructing the density matrix on entangled states after passing through turbulence [4, 5]. Note that here the atmospheric turbulence is simulated in the laboratory using a liquid crystal spatial light modulator (SLM) and the results are analysed using the aforementioned measurement schemes.
References
1. Gisin, N., et al., Quantum cryptography. Reviews of modern physics, 2002. 74(1): p. 145.
2. Ekert, A.K., Quantum cryptography based on Bell’s theorem. Physical review letters, 1991. 67(6): p. 661.
3. Ismail, Y., et al., Instrumentation limitation on a polarization-based entangled photon source. JOSA B, 2017. 34(6): p. 1084-1089.
4. Clauser, J.F., et al., Proposed experiment to test local hidden-variable theories. Physical review letters, 1969. 23(15): p. 880.
5. James, D.F., et al., On the measurement of qubits, in Asymptotic Theory of Quantum Statistical Inference: Selected Papers. 2005, World Scientific. p. 509-538.
Level for award<br> (Hons, MSc, <br> PhD, N/A)?
PhD
Apply to be<br> considered for a student <br> award (Yes / No)?
Yes
Primary author
Ms
Marie Louise Umuhire
(University of Kwazulu Natal, School of Chemistry and Physics, Westville Campus, Durban, South Africa)
Co-authors
Prof.
Francesco Petruccione
(UKZN)
Ms
Samkelisiwe Purity Phehlukwayo
(University of Zululand)
Dr
Yaseera Ismail
(UKZN)
