In 1929, Leó Szilárd invented a feedback protocol1 in which a hypothetical intelligence—dubbed Maxwell’s demon—pumps heat from an isothermal environment and transforms it into work. After a long-lasting and intense controversy it was finally clarified that the demon’s role does not contradict the second law of thermodynamics, implying that we can, in principle, convert information to free energy2, 3, 4, 5, 6. An experimental demonstration of this information-to-energy conversion, however, has been elusive. Here we demonstrate that a non-equilibrium feedback manipulation of a Brownian particle on the basis of information about its location achieves a Szilárd-type information-to-energy conversion. Using real-time feedback control, the particle is made to climb up a spiral-staircase-like potential exerted by an electric field and gains free energy larger than the amount of work done on it. This enables us to verify the generalized Jarzynski equality7, and suggests a new fundamental principle of an ‘information-to-heat engine’ that converts information into energy by feedback control.
At a glance
- On the decrease of entropy in a thermodynamic system by the intervention of intelligent beings. Z. Phys. 53, 840–856 (1929).
- Irreversibility and heat generation in the computing process. IBM J. Res. Dev. 5, 183–191 (1961).
- The thermodynamics of computation—a review. Int. J. Theor. Phys. 21, 905–940 (1982).
- Minimal energy cost for thermodynamic information processing: Measurement and information erasure. Phys. Rev. Lett. 102, 250602 (2009). &
- 2003). & Maxwell’s Demon 2: Entropy, Classical and Quantum Information, Computing (Institute of Physics Publishing,
- The physics of Maxwell’s demon and information. Rev. Mod. Phys. 81, 1–23 (2009). , &
- Generalized Jarzynski equality under nonequilibrium feedback control. Phys. Rev. Lett. 104, 090602 (2010). &
- A molecular information ratchet. Nature 445, 523–527 (2007). , , &
- The nonequilibrium thermodynamics of small systems. Phys. Today 58, 43–48 (July, 2005). , &
- 2010). in Stochastic Energetics (Lecture Notes in Physics, Vol. 799, Springer,
- Experimental demonstration of violations of the second law of thermodynamics for small systems and short time scales. Phys. Rev. Lett. 89, 050601 (2002). , , , &
- Fluctuations and irreversibility: An experimental demonstration of a second-law-like theorem using a colloidal particle held in an optical trap. Phys. Rev. Lett. 92, 140601 (2004). et al.
- Experimental realization of an optical one-way barrier for neutral atoms. Phys. Rev. Lett. 100, 240407 (2008). , , &
- Realization of a feedback controlled flashing ratchet. Phys. Rev. Lett. 101, 220601 (2008). et al.
- Tuning the effective coupling of an AFM lever to a thermal bath. Nanotechnology 18, 475502 (2007). , , &
- 1992). , & Feedback Control Theory (Prentice Hall,
- Second law of thermodynamics with discrete quantum feedback control. Phys. Rev. Lett. 100, 080403 (2008). &
- 1991). & Elements of Information Theory (John Wiley,
- Probability of second law violations in shearing steady states. Phys. Rev. Lett. 71, 2401–2404 (1993). , &
- Dynamical ensembles in nonequilibrium statistical mechanics. Phys. Rev. Lett. 74, 2694–2697 (1995). &
- Entropy production fluctuation theorem and the nonequilibrium work relation for free energy differences. Phys. Rev. E 60, 2721–2726 (1999).
- A mathematical theory of communication. Bell System Tech. J. 27, 379–423, 623–656 (1948).
- Nonequilibrium equality for free energy differences. Phys. Rev. Lett. 78, 2690–2693 (1997).
- Equilibrium information from nonequilibrium measurements in an experimental test of Jarzynski’s equality. Science 296, 1832–1835 (2002). , , , &
- Unidirectional rotation in a mechanically interlocked molecular rotor. Nature 424, 174–179 (2003). , , &
- Unidirectional molecular motor on a gold surface. Nature 437, 1337–1340 (2005). et al.
- Artificial Brownian motors: Controlling transport on the nanoscale. Rev. Mod. Phys. 81, 387–442 (2009). &
- Dissipation: The phase-space perspective. Phys. Rev. Lett. 98, 080602 (2007). , &
- Effect of external torque on the ATP-driven rotation of F1-ATPase. Biochem. Biophys. Res. Commun. 366, 951–957 (2008). et al.
- Nonequilibrium energetics of a single F1-ATPase molecule. Phys. Rev. Lett. 104, 198103 (2010). et al.
- Supplementary Information (500k)