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Previous Programs

2019 Intelligence in the Physical World

2019 Information as Fuel

2018 Agency in the Physical World
Awardees; RFP download

2016 Physics of the Observer
Awardees; RFP download

2015 The Physics of What Happens
Awardees; RFP download

2013 Physics of Information
Awardees; RFP download

2010 The Nature of Time
Awardees; RFP download

2008 Foundational Questions in Physics and Cosmology
Awardees; RFP download

2006 Foundational Questions in Physics and Cosmology
Awardees; RFP download

Peter Samuelsson
Lund University

Ville Maisi
Lund University

Klaus Ensslin
ETH Zürich

Christopher Jarzynski
University of Maryland

Project Title

Information-to-work conversion from classical to quantum – a nanoscale electronic demon in double quantum dots.

Project Summary

When the sun hits the earth, it warms the atmosphere. The atmosphere consists of gas molecules that move the faster, the hotter the atmosphere is. Imagine it would be possible, to slow down these molecules, i.e. extract their kinetic energy, and use it to drive an electric motor. This procedure would serve two purposes, namely to cool the atmosphere and to produce electric energy. Overall energy would be conserved. In physics there is a law called the second law of thermodynamics. This law states, that the above described procedure will not work. In order to cool the atmosphere, the extracted heat would have to be at least partially transported to another reservoir, for example the earth. So cooling always comes together with heating, for macroscopic systems this can not be changed.

For an individual gas molecule it is very well possible that it slows down, for example by hitting a soft barrier. This effect, however, is compensated by other gas molecules being accelerated so that the overall systems follows the second law of thermodynamics.

Technology has advanced to a point that the velocity of individual molecules can be monitored. Similarly, for small transistors realized in semiconductors, the transport of individual electrons, the carriers of charge leading to a measurable current, can be measured. If two transistors are close to each other one can tell whether an electron is in the right, the left or none of the transistors. This information, namely where the electron is located, can be used. Furthermore, the transistors can be externally manipulated through locally applied voltages or electric fields such that the location of an electron is determined by the potential landscape and the local fluctuations, which are always present for a system at finite temperature.

In modern physics we understand that information about a system and energy that one can extract from the system are related. We can thus build a system, for example consisting of two closely positioned transistors, which we can manipulate in a way that the electrons flow in the “wrong” direction, driven by the local thermal fluctuations. This requires that we know, i.e. have the information, where the electron is and how barriers have to be shaped in order for the electron to move against the applied voltage. We can thus use information to produce an electric current.

Knowing where an electron is, is a classical concept. Quantum mechanics tells us that if we know the location of a quantum object, we can not know in principle how fast it is. In this proposal we put all of these concepts together, namely quantum mechanics, information theory, thermodynamics and semiconductor technology. Our goal is to measure a current that is driven in a system, of which we have information which is used to manipulate critical components of the system. We will put information to work.

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