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Would using quantum mechanics for information processing be an impediment or could it be an advantage? This is the fundamental question in the field of quantum information processing (QIP). QIP is a young field with an incredible potential impact reaching from the way we understand fundamental physics to technological applications.
Information processing devices are pervasive in our society - from the 5 dollar watches to multi-billions satellite network - and have allowed the information revolution which is developing around us. It has transformed not only the way we communicate or entertain ourselves, but also the way we do science and even the way we think. All this information is manipulated using the classical approximation to the laws of physics, but we know that there is a better approximation: the quantum mechanical laws.
In late 1994, after hearing of Shor's quantum factoring algorithm, Professor Laflamme quickly realized that quantum computers would be hampered by the loss of quantum coherence (i.e. decoherence). In fact if decoherence is not taken care of, quantum computers lose their power.
After the seminal work of Shor and Steane, Professor Laflamme and his colleague Manny Knill laid down the mathematical foundation of quantum error correcting codes. With colleagues Miquel, Paz and Zurek, he has also discovered the most compact quantum error correcting code which corrects one quantum error. This quantum error correcting code has since been implemented using NMR, together with Knill, Negrevergne and Martinez.
After having looked at error correcting codes, his attention turned to taking care of errors which would happen while we are trying to correct errors. This lead to the threshold accuracy theorem which says that it is possible to compute for as long as desired with given accuracy, with reasonable (polynomial) amount of overhead, as long as the error rate is below a threshold. It is an important discovery as it shows that imperfection and imprecision of realistic devices are not fundamental objections to quantum computing. A few years later, using the multi-disciplinary characteristic of Los Alamos National Laboratory, he learned how to use Nuclear Magnetic Resonance (NMR) and collaborated with NMR spectroscopists both at Los Alamos and MIT to to better understand quantum information in an experimental setting.
The thread in Professor Laflamme's research has been to understand the limitations, both in theory and in experiments, on the control we have on quantum systems.
Current research projects include
Quantum information: Understanding the impact of manipulating information using the laws of quantum mechanics.
Robust quantum control: Developing methods to protect quantum information against noise through quantum control and quantum error correction for quantum computing and quantum cryptography.
Experimental quantum information processing: Implementing ideas and concepts of quantum information processing using nuclear magnetic resonance and developing scalable methods to control quantum systems.
Quantum cryptography: Theoretical and experimental investigations focussed on using the laws of quantum mechancis to transmit secure information, in particular using satellite communication.
Physical systems for quantum information processing: Developing “blueprints” for quantum information processors using various approaches such as linear optics quantum computing (LOQC).
Simulation of quantum systems: Finding ways to simulate quantum systems using quantum information processors.
Jochym-O'Connor T, Laflamme R.Using Concatenated Quantum Codes for Universal Fault-Tolerant Quantum Gates Physical Review Letters, Vol. 112, Issue 1, Article 010505, 2014.
An Introduction to Quantum Computing Oxford University Press 2006 (with P. Kaye & M. Mosca).
T. D. Ladd, F. Jelezko, R. Laflamme, Y. Nakamura, C. Monroe, and J. L. O’Brien. “Quantum computers.” Nature, 464:45–53, 2010.
Knill E, Laflamme R, Milburn GJ. “A scheme for efficient quantum computation with linear optics.” Nature 409,46-52, 2001.
Knill E, Laflamme R, Zurek WH. “Resilient quantum computation.” Science, 279:342–345, 1998.
Please see Google Scholar for a complete list of Professor Laflamme's publications.
The following news stories have featured Professor Laflamme's research:
1988 PhD, D.A.M.T.P., University of Cambridge
1984 Part III of Math. Tripos, D.A.M.T.P., University of Cambridge
1983 BSc, Physics, Universite Laval