As the world grapples with the energy crisis, a group of maverick scientists working on the fringes of accepted science has yet again come up with tantalising results. Last month in Japan, Yoshiaki Arata, a highly respected physicist in Japan and recipient of Japan's highest award, the Emperor's Prize, demonstrated the production of continuous excess heat from a simple experiment.

This low-energy nuclear reaction experiment was one more in the sporadic efforts to prove 'cold fusion', the discredited holy grail of unlimited cheap energy.

Using sample powders of zirconium oxide and palladium subjected to deuterium gas in a electrolysis cell, they were able to show generation of continuous heat along with helium. This is consistent with results they had produced in their earlier paper, proving it was reproducible.

More than ten groups have reported excess heat generation working with the same material. But reproduction has been the problem.

Arata used pressure to force deuterium gas into an evacuated cell that contained a palladium and zirconium oxide mix. By using powdered palladium, he increased the surface absorption area for deuterium. The excess heat generated by the fusion reaction kept the center of the cell warm for 50 hours.

So far the criticism has been that the experiments are not reproducible. Also, they do not give out the expected nuclear radiations like gamma rays and alpha particles (helium) or the high energy neutrons. Why should deuterium fuse in a solid when its density is much less than in a gas where it does not fuse?

Is the reaction nuclear or chemical is another doubt. Are we seeing products or simply contaminants?
It was in 1989 that cold fusion first whipped up heat when Stanley Pons and Martin Fleischmann, two electrochemists at Salt Lake City, Utah, spoke of controlled nuclear fusion in a glass jar. Fleishmann and Pons packed deuterium into a palladium lattice by electrolysis of heavy water. The palladium electrode absorbed a lot of deuterium and they claimed that some of these nuclei fused together, generating energy far in excess of any ordinary electrochemical reactions.

But flaws in the gamma ray spectra, as detected by the dept of energy, drove the last nail into the claim. However, since then groups have been working on the concept, but under a new name. Cold fusion went under cover and emerged as condensed matter nuclear science. Groups variously worked on 'clean energy' initiatives which used electrochemistry to convert elements and generate heat. Transmutation brought on the promise of alchemy!

At the beginning of 2007, The Royal Society of Chemistry in UK came up with a report on "cold fusion back on the menu" and this was followed by a symposium focusing on cold fusion (though not by that name!) at the American Chemical Society in Chicago.

There have been no satisfying theories that explain cold fusion.
In India, reputed theoretical physicist Prof K P Sinha has also been working on a suitable theory for CMNS based on lattice (structure) vibrations. As he explains, when electrons interact with these quanta of vibrations called phonons, the repulsion is overcome and two electrons sit on the same deuterium nuclei, allowing for two such nuclei to fuse. This has been observed with laser stimulated experiments on palladium where the surface enhanced Raman effect is enhanced 10 to the power of 14 times.

Commenting on the latest proof, Sinha says, “Arata's latest work convincingly demonstrates that it is genuine scientific phenomenon. Yes, it is nuclear fusion of deuteron pairs assisted by conditions in the solid state and screening provided by bound electron pairs. Dr David Nagel, research professor at George Washington University, Washington, has made detailed analysis and come to the conclusion that the energy released can be accounted for only by nuclear fusion reaction.”

Further, he explains, many experimental groups have shown the production of nuclear ash, for eg. helium4, helium3, tritium, neutrons,and X-rays etc. “It is high time experimental work is started in India. This low cost (compared to hot fusion) process may solve the energy problem.”

According to him, cold fusion conditions are "difficult but possible". Electrolysis may have to be done for 50 hours before the deuterons align along the line defects where they are confined and head-on collision is possible.
Cold fusion was stopped mainly because of propaganda from the hot fusion group whose funding runs into 100 billion dollars. "Cold fusion, on the other hand, costs less." He believes that scientists who have been working on the concept are all honest.

In India too, work has been done and as effectively buried. Now there is a resurgence of interest. Dr M R Srinivasan, former chairman of the Atomic Energy Commission of India said recently that "there is some science here that needs to be understood… the neglect should come to an end."

How fusion happens

Fusion of deuterium (hydrogen) nuclei into helium, with release of energy, is also what happens in the sun, albeit at high temperatures and in gaseous plasma. What cold fusion or condensed matter nuclear science offers is the same in a solid state.

Why this is important is because it opens possibilities of an infinite source of energy as released in the interiors of the sun without the need for such high temperatures and pressures.

Normally, nuclei resist coming close due to repulsion of like charges on protons but if this could be overcome and nuclei come close enough, a strong nuclear force takes over and nuclei fuse to become heavier elements. In the interiors of stars the high temperature provides this energy. The energised nuclei randomly dash about and merge.

This can also be done by generating huge electric fields across the solid, like in pyroelectric crystals (that generate electric fields on being heated). It has been experimentally proved.

Once the fusion reaction starts, it generates so much excess heat that it becomes a sustained chain reaction. The hydrogen bomb is an uncontrolled fusion chain reaction.

Theoretically speaking

Sinha is the oldest surviving physicist at the Indian Institute of Science celebrating its centenary year. He was responsible for setting up the Center for Theoretical Studies, whose offshoots are many today.

Starting his career at the prestigious Bell Labs, Sinha proposed a theory for semiconductor luminiscence behaviour which increased due to impurities, but till a limit. This was based on phonon-magnon (quanta of magnetic momentum when disturbed) interaction, he showed.

Having worked at the prestigious Bell Labs in the 60s, he came to IISc on the assurance of being allowed to work in any area. Starting work in solid state physics, both in theory and experiment, he went on to develop theories like the quantum theory for solid interaction, interaction of radiation with matter, gravity at extreme density, etc.
Low temperature superconductivity is another area he is active in and he is hopeful that it is going in the right direction. In fact, he had predicted photon induced superconductivity, now pursued actively and confirmed, way back in 1968.

More recently, and still pursuing work after retirement, Sinha along with S K Srivastav developed a theory that took Einstein's general relativity to a higher dimension. The geometry of space, time and energy matter is inter-convertible, they found, confirming what Einstein said. "The geometry of space-time is not inert but physical." First proposed by Italian physicist Ricci, the theory speaks of Riccions or quantums of this physical geometry.
Currently, Sinha is INSA honourary scientist at Physics department, IISc. He has written 6 books, has over 300 publications and 2 patents on solid-state materials besides winning the Bhatnagar award, etc.