Helgoland: Searching for the past and future of quantum physics on a tiny island

I went to more scientific conferences that I do not count, but a recent meeting held on the island of Helgoland to celebrate the centenary of quantum mechanics is one of the strangest – in the right direction.

This tiny German island, barely more than a kilometer long and far in the North Sea, looks like a coastal seaside resort at the bottom: the sea less than even in summer, the small streets full of cheap gift shops and the smell of fish and fries and ice cream. Imagine now that each round, you are launching into physicists of the Nobel Prize winner, inventors of the theory of quantum information and experimental at the forefront of quantum technologies, fresh to discuss their work at the town hall, next to the crazy golf course. It is rather wonderful.

The reason why we are here is revealed on a rock on the way to the cliff. He wears a bronze plaque (see below) which suggests that it was there that the physicist Werner Heisenberg, during an excursion to request a relief from his hay fever in 1925, invented quantum mechanics. Unfortunately, this is not really true – at best Heisenberg has sketched ideas here which, thereafter, he and others made a complete quantum theory. And the version we know more today was unveiled at the beginning of 1926 by Erwin Schrödinger, who introduced the function of waves as a means of predicting the evolution of a quantum system.

All the same, if you want to assign a centenary to quantum mechanics, it is the obvious year to choose. And whatever the quantity of Helgoland’s story, was due to Heisenberg’s self -invitation – he wrote the story of his breakthrough only years later – the distant island is a rather special place to organize the party.

And what a party is. It is difficult to imagine such an eminent cast of assembled quantum physicists. There are four laureates of the Nobel Prize here: Alain Aspect, David Wineland, Anton Zeilinger and Serge Haroche. Between them, they have established the reality of the strange characteristics of quantum mechanics, as the way in which the properties of a particle may seem instantly contingent to what we measure for a second, a “tangled” particle, whatever its distance. They have also created some of the manipulation techniques for individual quantum particles that are now used to build quantum computers.

But here is the thing. I suspect that these great alumni (ISH) would agree with me that it is the young generation who now has the best hope of giving meaning to what quantum mechanics really mean, and to transform its notoriously counter-intuitive nature into new technologies and a new understanding of nature. Quantum mechanics are known to admit many different interpretations of what mathematics of theory tell us about the real world, and most of the old guard has already taken a stand and seems unlikely to change their opinions.

This impasse was obvious in a round table the first evening when the aspect, Zeilinger and Gilles Brassard, founder of quantum cryptography of the University of Montreal, Canada, pronounced with equal confidence in the fundamental meaning of quantum mechanics while being in direct contradiction.

To be fair to these veterans, their ideas were formed in the face of skepticism (or worse) of their peers on the same value of thinking of such “fundamental” questions. They emerged from the era of “Shut up and calculate” – the sentence invented by the American physicist David Mermin to describe how he was considered bad to wonder what the quantum mechanics meant, his duty being simply to resolve the equation of Schrödinger. It is not surprising that they had to cultivate robust views and thick skins.

The youngest researchers seem less inclined to be dogmatic about quantum foundations, and perhaps more ready to collect and repress different interpretations according to their usefulness for the problem to be accomplished. A little of many worlds here, a little of the interpretation of Copenhagen there, all as tools of reflection with rather than declarations on reality.

The new generation is also less tirelessly. For example, Vedika Khemani at the University of Stanford, California, told the meeting on rich and beautiful connections between ideas in condensed material and quantum information, a connection that withdraws us from the storage of information on magnetic strip in the 1950s to essential error correction techniques for quantum calculation today.

Exploiting quantum mechanics to build new technologies is increasingly in vogue, but theorists are not relaxing either. Flaminia Giacomini at the Federal Institute of Technology in Zurich, Switzerland, was one of the many speakers who thought we could have a clearer image of what the quantum mechanics mean if we can reconcile it with gravity, seeking a marriage of discreet and gravity with the smooth and continuous world required by general refection.

You may have thought that everything is to explore non-testable and barely lasting ideas in string theory, an attempt to create such a union. But the truth, as Giacomini said, is that “we have no experimental evidence that we must quantify the gravity” – we do not even have empirical reasons (even if there are many theoreticals) why gravity must be a quantum force at all, as the other three forces of nature are clearly.

What is exciting is that, at least, is something that we can hope to test in the near future, for example by seeing if we can tangle two objects only by their gravitational interaction. The challenge here is that objects must be large enough to produce a significant gravitational force, but small enough to show quantum behavior: the nanoparticles of, let’s say, silica or diamond can do the trick. Several speakers have expressed their confidence that we take up this challenge in about a decade.

For me, a key revelation from Reunion is that so many quantum theory and experience flaps are now tangled. Pull on one and you affect others. Understanding more about quantum gravity from extremely sensitive experiences on trapped particles and you could enter into the black hole information paradox and emerge with new ideas on the correction of errors for quantum computer science or a new idea of ​​winding “topological” quantum states.

It seems that work in one of these areas can even help us understand the old questions that have disturbed Heisenberg and his colleagues: what happens when we make a measure on a quantum particle, and how does it transform quantum into a classic? In any case, saying that a century later, we are still fighting with these old questions is the wrong way to see it. We have rather discovered that quantum mechanics is much richer, more useful and more astonishing than its founders could have gone.