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The measurement problem in physics

By Hamish Johnston

This morning on BBC Radio 4, the mathematician Roger Penrose, physicist Basil Hiley, and philosopher Simon Saunders had a lively discussion about the “measurement problem in physics” with broadcaster Melvyn Bragg.

You can listen to it here

I got to thinking that the growing interest in building quantum computers and other information systems has put a practical spin on the measurement problem.

The “problem” the open question of how (or even if) a measurement transforms an entity such as an electron from being a ghostly combination of quantum states to being very definitely in just one state.

Many physicists believe that the clever manipulation of such ghostly combinations could be done in quantum computers, allowing such machines to outperform conventional computers on some tasks.

Such quantum computers would rely on making the right measurements — and avoiding the wrong measurements — so what had been mostly a philosophical/mathematical debate about measurement has a growing technological relevance.

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  1. Starfart

    I will say this much: I for one do NOT happen to care a flying gob of SPIT beyond my regular and steady allegiance to technological progress, over whether there may happen to be an application of whatever is discerned by the currently fashionable investigations of ‘quantum computing’. Technology is NOT the same thing as science, and I shouldn’t have to remind anybody that technology never once EVER supplied a reciprocal input back into a genuinely scienftific understanding of the PHYSICS involved. I frankly do not care whether (so far) half-baked ideas or observations MAY be applicable to computer technology or amenable to any other technological application.
    Not only is this avenue physically uninteresting, it is as boring as listening to string theorists proclaiming they’ve got all the answers. Is the subject of quantum mechanics to be continuously swamped by the constant allusion to its potential applications? I unhestatingly admit these potential applications are almost certain, eventually, but that isn’t the point! TECHNOLOGICAL APPLICATION ISN’T THE POINT for a forum that claims PHYSICS as its domain!
    Wouldn’t this approach be better served by something called “TechnologyWorld” rather than “PhysicsWorld”? Why do we have to read dribble that any subscriber already appreciates? Why can’t we get – just HALF the time at least – a decent and in-depth accounting of the actual state of affairs in terms of both theory as well as experiment? Where are the articles that furnish an in-depth treatment complete with sufficient technical background? WHERE?
    If not, I would warn that you may soon have to change your name to “NewPhysicsWorld” – in the footsteps of that illustrious rag that has already done much to turn the communication of science into a near farce. Watch out. It could get awful tricky if you let the so-called ‘bottom line’ overtake your whole reason for being.

  2. jjeherrera

    I think the note answers by itself the relevance of the interaction between science and technology. What used to be “gendankenexperiment” are becoming “realexperiment” thanks to new technologies, and this is of great value to the advancement of physics, not just technology.


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