A Thermodynamic Limit on Brain Size

If our brains have to be cooled like computer chips, is there a limit on how big they can be?

In recent years, chip makers have conlcuded that the race to produce ever faster circuits is a fool’s game. As the clock speed increases, the amount of energy lost as heat becomes too large to dissipate efficiently and in any case, the waste is unjustifiable.

That raises some interesting questions about the human brain, says Jan Karbowski at the Sloan-Swartz Center for Theoretical Neurobiology at the California Institute of Technology. Karbowski points out that the problem of heat transfer could be a serious factor shaping brain evolution and so has embarked on a program to determine the relationship between brain temperature, its size, cerebral power generated and neural activity.

The question on Karbowski’s mind is whether there is any thermodynamic limit on brain size. And if so, does 5 kg, which Karbowski says is the mass of the largest mammalian brain, approach that limit?

Source: Arxiv blog.

Also see “Why Worry About This Sci-Fi Stuff Now? Mindfiles, Mindware and Mindclones” on IEET.

Quantum tunneling with nanowires

Nanowires

Quantum tunneling is the capability of a particle to inhabit regions of space that would normally be off-limits according to classical mechanics. This research observes a process called a quantum phase slip, whereby packs of roughly 100,000 electrons tunnel together from higher electrical current states to lower ones. The energy locked in the motion of the electrons as they phase slip is dissipated as heat, causing the nanowires to switch from a superconducting state to a more highly resistive one.

Source: University of Illinois. The researchers hope this effect could be used for quantum computing.

Also read “New rotors could help develop nanoscale generators” about more breakthroughs in nanotechnology from Eurkalert.