Friday, March 12, 2010

Can we detect quantum behavior in viruses?

The weird world of quantum mechanics describes the strange, often contradictory, behaviour of small inanimate objects such as atoms. Researchers have now started looking for ways to detect quantum properties in more complex and larger entities, possibly even living organisms.

A German-Spanish research group, split between the Max Planck Institute for Quantum Optics in Garching and the Institute of Photonic Sciences (ICFO), is using the principles of an iconic quantum mechanics thought experiment -- Schrödinger's superpositioned cat -- to test for quantum properties in objects composed of as many as one billion atoms, possibly including the flu virus.

New research published on March 11 in New Journal of Physics describes the construction of an experiment to test for superposition states in these larger objects.

Quantum optics is a field well-rehearsed in the process of detecting quantum properties in single atoms and some small molecules but the scale that these researchers wish to work at is unprecedented.

When physicists try to fathom exactly how the tiniest constituents of matter and energy behave, confusing patterns of their ability to do two things at once (referred to as being in a superposition state), and of their 'spooky' connection (referred to as entanglement) to their physically distant sub-atomic brethren, emerge.

It is the ability of these tiny objects to do two things at once that Oriol Romero-Isart and his co-workers are preparing to probe.

via Can we detect quantum behavior in viruses?.

Tantalizing glimpse of macroscopic quantum effects

The weird laws of quantum mechanics govern how molecules, atoms and smaller particles behave, but quantum phenomena sometimes "leak up" to macroscopic scales, researchers at the University of Illinois have found. They have demonstrated that, counter to classical Newtonian mechanics, an entire collection of superconducting electrons in an ultrathin superconducting wire is able to "tunnel" as a pack from a state with a higher electrical current to one with a notably lower current, providing more evidence of the phenomenon of macroscopic quantum tunneling.

Alexey Bezryadin and Paul Goldbart led the team, with graduate student Mitrabhanu Sahu performing the bulk of the measurements, with the results appearing in Nature Physics.

Quantum tunneling is the capability of a particle to inhabit regions of space that would normally be off-limits according to classical mechanics. The team's 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. This switching of states allows the tunneling of the phase slip to be observed.

Goldbart describes a quantum phase slip as a phenomenon that allows the spatially extended structure of superconductivity; "to undergo a kind of quantum mechanical rip or tear, one where the entire extended behavior of the superconductivity tunnels its way through a classically forbidden set of configurations." ... - scienceagogo

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