Key Articles 2

Zeeya Merali (Based on Jonjoe McFadden)


New Scientist:  8th December 2007

This recent article in the New Scientist revives a long-established idea that the origin of life on Earth could derive from a quantum process. The first to suggest this appears to have been Schrodinger in his 1944 book, 'What is Life? The idea is relaunched by Jonjoe McFadden of the University of Surrey UK, who has also proposed the idea of an electromagnetic field as a substrata of consciousness. 

The proposal is in many ways the mirror image of the proposals for quantum consciousness. The quantum process is suggested to provide an explanation for something that macroscopic science has failed to explain, and the main argument against the quantum is the same as in the case of consciousness, that is that decoherence in the conditions involved would be far too quick for quantum coherence to be relevant. As with the quantum consciousness idea, proponents of the quantum view have argued for possible shielding of the quantum processes.

The origin of life is not as hard a problem as consciousness, but it has certainly proved difficult. The idea that life arose from some primordial soup of molecules is inherently plausible. The difficulty arises in getting the molecules to combine in the right order. The simplest self-replicating structure is estimated to require 165 base-pair molecules placed in the right order, and the odds against getting the this order is 4^165, a number said to be greater than the number of electrons in the universe. Of course, if nature made enough, tries for long enough it should get there eventually. However, life on Earth appeared quite soon after the planet became at all suitable for it, making the 4^165 chance a bit improbable.

McFadden proposes that a form of quantum computing arose in the primordial conditions allowing a 'search' of all the possible ordering of the molecules, and leading to the discovery of a sequence that self-replicated. Some support is given to his idea by the suggestion that the speed at which nucleotide bases are matched up when cells split requires quantum processes.

As with quantum consciousness, the main problem for the proposal is the speed at which quantum decoherence would be expected to occur in the type of conditions that would allow the origin of life. However, two other researchers, Asoke Mitra and Garge Mitra-Delmotte have suggested how quantum processes could have been shielded, in a manner rather akin to Hameroff's idea of quantum processes being shielded within the microtubule. They focus on sub-sea vents that have been a favourite location for the origin of life in recent years. Another scientist, Michael Russell at the University of Glasgow had already shown that the necessary molecules could react with iron sulphide found close to the vents. Mitra and Mitra-Delmotte argue that chambers found near sub-sea vents could shield quantum processes. Magnetic fields generated by the iron sulphide are suggested to protect the quantum states of the necessary molecules. The Mitras point out that magnetic fields are used in an analogous manner in proto-type quantum computers, in order to maintain the entanglement of particles used as qubits. The idea is suggested testable by means of existing technology.

Substantiation of the idea would not in itself appear to prove that consciousness is explained at the quantum level. However, if quantum processes were seen to have been involved in the origin of life, that would seem to be an inherent plausibility that the adaptive advantages of the speed of quantum search processes would have been incorporated into living organisms.





Quantum entanglement of K+ Ions, multiple channel states & the role of noise in the brain
 
Bernroider, G. & Roy, S. (2005)
 
International Society for Optical Engineering (SPIE) Vol. 5841

Gustav Bernroider of Salzburg University has proposed that quantum coherence and entanglement in the ion channels of neurons underlies information processing in the brain and ultimately consciousness (1&2.).

Ion channels are a crucial component in the axonal spiking/synaptic firing model of neuronal signalling and information processing. The axonal signal starts from the body of the neuron and proceeds down the axon, by means of a fluctuation in the difference in electrical potential across the membrane that forms the exterior of the axon. The membrane is formed by a double layer of lipids. The ion channels consist of protein molecules inserted through the lipid bi-layer. The axon fires when sodium (Na+) ions flow in through one set of ion channels, and subsequently returns to its resting state when potassium (K+) ions flow out through another set of ion channels. This process continues down the length of the axon until it reaches the synapse, which it causes to fire, and thus communicate with other neurons. Ion channels are thus a key mechanism in the brain's signalling and information processing.

Bernroider bases his theory on recent studies of ion channels. These have been made possible by advances in high-resolution atomic-level spectroscopy and accompanying molecular dynamics simulations. His theory was principally developed in a 2005 paper with co-author Sisir Roy (1.). In this work, they draw particularly on the work of the MacKinnon group, and on studies of the potassium (K+) channel, especially the closed state of this channel. (3-20.)

The functioning of the K+ channel occurs in two stages, firstly, the selection of K+ ions in preference to any other species of ion, and secondly voltage-gating that controls the flow of these favoured K+ ions. The authors say that the traditional understanding of both functions has been altered by the recent studies. In its closed state, the channel is now seen to stabilise three K+ ions, two in the permeation filter of the ion channel and one in a water cavity to the intracellular side of this permeation path. In the case of the channel's voltage gating, the electrical charges involved, which were previously thought to act independently of the surrounding proteins and lipids, are now seen to be coupled to these proteins and lipids, and are thus involved in the gating process.

Atomic-level spectroscopy has revealed the detailed structure of the K+ channel in its closed state. The filter region of the channel has a framework of five sets of four oxygen atoms, which are each part of the carboxyl group of an amino-acid molecule in the surrounding protein. These are referred to as binding pockets, involving eight oxygen atoms in total. Both ions in the channel oscillate between two configurations (1).

Bernroider and Roy's calculations lead them to claim that ion permeation can only be understood at the quantum level. Taking this as an initial assumption, they go on to ask whether the resulting model of the ion channel can be related to logic states. Their calculations suggest that the K+ ions and the carboxyl atoms of the binding pockets are two quantum-entangled sub-systems, and they equate this to a quantum computational mapping. The K+ ions that are destined to be expelled from the channel could encode information about the state of the oxygen atoms in the axon membrane (1.).
 
In a later paper, presented at the Quantum Mind 2007 conference (2.), Bernroider proposed that different ion channels could be non-locally entangled, thus proposing a quantum process over an extended area of the axon. Given the importance of the ion channels in brain functioning, this model would give quantum coherence and non-locality in the axon membrane an integral role in the brain's signalling and information processing.
 
Further to this, Bernroider and Roy have pointed out a similarity between the structure of the K+ ion channel and some recent proposals for building quantum computers, in which ions are held in microscopic traps (20-27.).

The authors argue that their model is well protected against decoherence, which has always been the most cogent criticism of quantum consciousness proposals. In particular, they claim that Tegmark's calculations do not apply to their model (28.). The authors agree that for ions moving freely in water, Tegmark's coherence time of 10^20 seconds would apply. However, they argue that the situation of the ions held in the permeation filter of the ion channel is markedly different, with a temperature about half the prevailing level for the brain, and the ions protected from decoherence by the binding pockets and the adjoining water cavity (1).

A New Theory of Quantum Consciousness?
It may be debatable as to whether Bernroider's proposals amount to a new theory of quantum consciousness.  In a paper in Neuroquantology in 2003 (29.), Bernroider appeared to favour David Bohm's concept of an underlying implicate order, from which arises the explicate order of classical physics that we experience in everyday life. However, Bernroider and Roy's 2005 paper and Bernroider's extension of this at the 2007 conference propose a new system of quantum coherence in the brain that is distinct from any of the earlier quantum consciousness models.

Bernroider's theory could potentially be a vehicle for transfering consciousness from the implicate into the explicate order of David Bohm. Bernroider differs from Penrose and Hameroff's Orch OR model in his emphasis of the axons and membranes, as opposed to the dendrites and the cytoskeleton. However, there are similarities between the two models in that both of them propose quantum coherence, non-locality and subsequent wave function collapse linked to the brain's macroscopic information processing activity. As it stands, Bernroider's proposals only deal with information processing in the brain rather than consciousness as such. However, it appears possible that wave function collpase in the ion channels might link to Penrose's proposed geometry of spacetime, just as readily as wave function collapse in the cytoskeleton.

Bernroider's theory is distinct from all earlier quantum consciousness theories in locating its mechanism in structures that are central to mainstream theories of the brain's information processing and production of consciousness. If future experimentation were to substantiate the Bernroider proposals, this would involve a revolution in neuroscience of the most profound kind.





Gregory Engel et al

Dept. of Chemistry, University of California, Berkeley

Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems

Nature, vol 446, pp.  782-786, 12 April 2007

This paper points out that photosynthetic complexes are adapted to capture light, and put its energy into long-term storage. This process has normally been described in classical terms, and quantum coherence has been to a good extent ignored in the traditional analysis. However, the possibility of quantum coherence has been predicted, and in this paper the authors describe evidence for long-lived quantum coherence being involved in energy transfer within photosynthetic systems. The wavelike process is thought to account for the efficiency of the sytem, because it allows the sampling of large areas of phase space, in order to find the most efficient path, or to transfering energy to the area in the lowest energy state.
 
The Engel et al experiment involved electronic spectroscopy to observe the evolution of electronic coherence. Quantum beating was found to last for 660 fs, which was much more than the 250 fs estimated for conventional models. Conventional models had assumed that quantum coherence would be rapidly destroyed, and had therfore not factored it into their models of photosynthetic systems.

By contrast, the authors conclude that long-lived quantum coherence must play an active role in photosynthetic systems. A quantum coherent system allows sampling in order to direct energy to the lowest energy state. The system is viewed as performing a quantum computation, in which it senses many states simultaneously and from these selects the correct answer. This is seen as analogous to Grover's algorithm, allowing both the discovery of the lowest energy state and the transfer of coherence. This is more efficent than any classical search engine. Protein is seen as providing the structure in which coherence can be preserved and at the same time modulating the coherence as a result of the local dielectric environment.





The Ascent of Life

Paul Davies

Macquarie University, Australia

New Scientist, 11^th December 2004

As a physicist, Paul Davies, starts by noting that living organisms represent a state of matter in a class apart from all other matter. The cell is the basic subunit of living matter, and is now understood to be full of nanomachines in the form of the organelles, cytoskeleton, receptors and synapses.

Davies discusses Heisenberg’s uncertainty principle as a possible objection to quantum involvement in brain processes. Uncertainty is a potential problem for living organisms, because replication requires the accurate coordination of molecules. Uncertainty principle is usually explained in terms of not being able to know both the exact position and exact momentum of a quantum particle. The more one knows about one, the less one can know about the other. However, the same constraint applies to other aspects of a quantum particle, such as time and energy. Time uncertainty represents a problem with respect to living organisms because the uncertainty compromises the accuracy of timing that is vital to life, which depends on the timely organisation of molecules for replication and other processes.

In fact, it is possible to calculate the minimum size of a clock of a given accuracy. This calculation derives from the physicist, Eugene Wigner, in the 1950s. Wigner’s calculation has thrown up some interesting correlations in terms of various organisms, in circumstances where these can be regarded as clocks. For mycoplasma cells, it is possible to calculate a reliability time limit of about an hour for internal time keeping. It now transpires that their reproductive cycle also takes an hour. The internal components of the cell are much smaller than the cell itself and have a correspondingly shorter period of accurate time keeping, but despite this similar instances arise at the cellular coponent level. Thus the polymerase enzyme that moves along the unzipped strands of DNA covers a bit over 100 base pairs per second, which is in line with the minimum speed required to retain accuracy of timekeeping at the quantum level. Protein folding times have also been shown to be close to the limit allowed if accuracy of quantum time keeping is to be retained.

It is also suggested that quantum mechanics may play a more positive role in organisms. Apoorva Patel at the Indian Institute of Science proposes that quantum mechanics could be involved in speeding up the process by which polymerase finds bases to bind to the DNA strand. It is suggested that this could involve an application of Grover’s algorithm, an algorithm that manmade quantum computers might eventually use to search massive and jumbled databases. The DNA strand has four bases, three letters of this strand at a time code for the amino acids, and there are 20 amino acids. Biologists have often speculated about the apparently arbitrary nature of these numbers. Patel points out that 3, 4 and 20 would emerge naturally from the application of Grover’s algorithm.

Genetic mutation has often been suggested to be the result of quantum fluctuations. Jonjoe McFadden and Jim Al-Khalili at Surrey University suggested that the ability of bacteria to respond to shortage of nutrients might have a quantum origin.

A final suggestion is that quantum processes might have been involved in the origin of life on Earth. The odds against a replicator emerging from a soup of molecules are usually calculated to be very high, and some form of quantum search, making use of Grover’s algorithm could have facilitated the emergence of the first replicators. If quantum processes were involved in the origin of life, it is likely that they would have been retained as organisms evolved.

At the end of his paper, Davies discusses the extent to which decoherence is a problem for quantum processes in biological tissue. He agrees that a simple model shows that decoherence in biological tissue will happen much too quickly for quantum processes to be biologically useful. However, he points out that simple models often fail to take account of all the relevant features in real systems. For instance, in some situations, decoherence does not proceed at a uniform rate, but the collapse of part of a system to the classical level creates conditions that protect the quantum coherence of the remainder of the system.

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