The UCL/ICTEAM IEEE Student Branch along with prof. Denis Flandre is glad to invite you to the following seminar :

**“Energy Recovery and Recycling in Computation from Landauer principle to Reversible Adiabatic Logic”**

given by Alexei Orlov, professor at University of Notre Dame, IN, USA.

The event will be held on Thursday **28th of April at 11:00 am** in the **Shannon Room** (Maxwell A.105). Coffee and collation will be served.** **

**Abstract: **Is there a minimum energy required to compute a bit of information? Does the choice of state variable used to represent information affect the energy dissipated in computation? These questions are taking on more than mere academic importance, as evidenced by the heat produced by modern laptop computers. Indeed, energy use in computation has become the dominant challenge in the design of computational logic and systems. In CMOS logic the energy used to represent the bit of information is dissipated to heat at each logic transition. This way of processing information is very wasteful of energy and does not scale well as devices shrink to nanoscale dimensions. How low can dissipation be pushed? Recent experiments have shown that ultra-low energy dissipation is possible, the question becomes how to extend these results to real computing systems. One approach is to use reversible logic implemented with adiabatic circuits to avoid information destruction, so that energy can be recovered and loss is minimized in state transitions. In such a system the energy needed to process information is sent to the logic by power clocks, and then returned from the logic when the computation is complete. To achieve overall energy savings the energy returned must be recycled and reused in the next computation, rather that dissipated to heat in the clock generator.

This presentation will examine the fundamental issues involved in computation, including the Landauer Principle and the use of charge as a state variable, and show experimental results testing theoretical predictions. Implementations of reversible logic using adiabatic CMOS will also be discussed.

**Biography**: Alexei O. Orlov is a Research Professor at the Department of Electrical Engineering, University of Notre Dame, USA. He received his M.S. degree in Physics from the Moscow State University in 1983. From 1983 to 1993 he worked at the Institute of Radio Engineering and Electronics of the Russian Academy of Sciences, Moscow. During that time he conducted research on mesoscopic and quantum ballistic effects in electron transport of GaAs field-effect transistors.He received his Ph.D. from the same Institute in 1990. He has been a visiting fellow at the University of Exeter, UK in 1993, and joined the Department of Electrical Engineering at the University of Notre Dame, IN, in 1994. His topics of research include experimental studies of single-electron devices and sensors, nanomagnetics, quantum-dot cellular automata, IR nanosensors, and more recently, low power computation and Si CMOS Q-bit (in collaboration with INAC, Grenoble). Alexei Orlov has authored or co-authored more than 70 journal publications and 3 book chapters.