Decoupling system and environment

Our first guest-post is by Diogo O. Soares-Pinto (IFSC-USP), who is an expert in NMR experiments. Diogo writes about the first two talks of today (14.08.13) at Paraty IV.
Thanks a lot Diogo!

And if you want to contribute to our blog, please drop me a line (fmelo .at.

———— guest-post by Diogo O. Soares-Pinto

In general, all physical systems are affected in some sense by their surroundings. The effect of such coupling between system and environment is the loss of coherence, also known as decoherence, which means a transition from a quantum a classical world. In today’s first two talks Alexandre Souza and Gonzalo Alvarez showed us how to circumvent this effect and even take some advantage of it.

In the beginning of the first morning session, Alexandre Souza from CBPF, Rio de Janeiro, showed an interesting combination between dynamical decoupling techniques and quantum gates useful for quantum computing, followed by an experimental implementation in NV-centre of diamonds. In the first part of the talk, Alexandre explained that such dynamical decoupling (DD) pulse sequences are very important to avoid the effects of the system-environment interaction, by “simply” refocusing such coupling. These pulse techniques have a long history of contribution to Nuclear Magnetic Resonance (NMR), Electron Paramagnetic Resonance (EPR) and optical studies, and in the last years were adopted by quantum computing community as possible quantum error correction technique. In the second part of the talk, Alexandre showed that he and his collaborators created a DD pulse sequence interleaved with quantum gate operations for which the fidelity of the experimental implementation was over 98% for gates that are much longer than the decoherence time!

In the second talk, Gonzalo Alvarez from Weizmann Institute in Israel, continued to discuss the origins and applications of DD pulse techniques to different research areas. He showed that the engineering of the pulse sequences can be useful to extract information about the physical system and even about the environment itself! Gonzalo presented a new proposal by him and collaborators called Selective Dynamical Recoupling (SDR) sequences that is extremely useful for spectroscopy. He also showed some applications of this technique to NMR studies of diffusive processes, together with some experimental implementation. It seems that a huge number of applications are about to come!

I believe that anyone who knows a little bit about NMR and related techniques got really excited with these two talks! Congratulations to Alexandre and Gonzalo!


2 thoughts on “Decoupling system and environment

  1. Pingback: Random – but not quite: exploiting quantum decoherence as a tool for characterizing unknown systems | Paraty 2013 | Gonzalo Agustin Alvarez

  2. Pingback: Random – but not quite: exploiting quantum decoherence as a tool for characterizing unknown systems | Seminar | Gonzalo Agustin Alvarez

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