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Department of Physics

Thermodynamics and the Shoulders of Einstein and others

"A theory is the more impressive the greater the simplicity of its premises, the more different kinds of things it relates, and the more extended its area of applicability. Therefore the deep impression that classical thermodynamics made upon me. It is the only physical theory of universal content concerning which I am convinced that, within the framework of applicability of its basic concepts, it will never be overthrown (for the special attention of those who are sceptics on principle).”

- Albert Einstein, 1946 (Autobiographical Notes), English translation by Paul Arthur Schilpp

Research and Motivation

Can physical laws explain living systems?

Molecular biology may provide a material basis (the building blocks) of life (causa materialis), but physics has to explain why things happen (causa efficiens). Our dream is to understand biological function based on physical principles or - in other words - to derive biological function from physics.

One key idea is to start from the 2nd law of thermodynamics in Einstein's formulation, as suggested by Konrad Kaufmann, and apply it to hydrated interfaces. In this way different biological functions are derived from looking at the 2nd law for different thermodynamic states.


Communication and Integration in Biology – What makes the cell a cell?

What makes the cell a unit? What orchestrates it or how does one end know about the other? We have demonstrated that linear and nonlinear acoustic pulses can propagate through hydrated interfaces (e.g. lipid monolayers) and that these pulses can be regulated by the thermodynamic state. In particular, pulse stability is largely facilitated by the system being near a phase transition.

Following Einstein's view on thermodynamics, we consider these pulses as the result of non-zero first derivatives of the entropy potential (Einstein 1910). We hypothesize that such pulses play a vital role in biology, forming the foundation of integration and communication in biology from cells, multicellular structures, organs up to the brain. In this sense these pulses would represent a physical origin of Neuroscience. For more detailed information, see references 44, 45, 55 and 48 (further publications on pulses 34, 47, 49, 56)

The control of catalytic activity by the thermodynamic state (fluctuations or - in other words - second derivatives of the entropy potential) is a further step which integrates the main pillar of Biochemistry: Enzymes. State changes - isothermal and/or adiabatical - can regulate enzymatic activity (Kaufmann 1996). The latter can and will feed back on the state for instance by chemistry (e.g. by changing lipids and thereby the membrane state). Experimentally, we will study the role of this integration of biochemistry into a thermodynamic picture using Fluorescence Correlation Spectroscopy (FCS). With this technique we hope to gain deeper insight into the physical foundations of the cell.


Health and departure from health – Physically controlled (cell) adaptation.

The described integration of thermodynamic state, pulses and biochemistry opens the door to studying adaptation, growth and structure formation of biological systems. If a certain thermodynamic state (e.g. near a phase transition) is favored, i.e. optimizes the system in some sense, external perturbations will trigger processes that drive the system back to this state. In other words, the system adapts.

We will test this hypothesis on living systems and study its role in addiction and withdrawal. Further, we will investigate the formation of cellular networks and how growth and connectivity relates to the existence of pulses and its coupling to enzymatic activity via state. This ultimately should test whether these ideas hold also for a physical foundation of the brain.