Thursday, 21 August 2008

This Means Something

From the University of Rochester :
Most scientists have believed that the instant a quantum object was measured it would "collapse" from being in all the locations it could be, to just one location like a classical object. Jordan proposed that it would be possible to weakly measure the particle continuously, partially collapsing the quantum state, and then "unmeasure" it, causing the particle to revert back to its original quantum form, before it collapsed.
In the latest issue of Nature News, Postdoctoral Fellow Nadav Katz explains how his team put the idea to the test and found that, indeed, he is able to take a "weak" measurement of a quantum particle, which triggered a partial collapse. Katz then "undid the damage we'd done," altering certain properties of the particle and performing the same weak measurement again. The particle was returned to its original quantum state just as if no measurement had ever been taken.

Because theorists had believed since 1926 that a measurement of a quantum particle inevitably forced a collapse, it was said that in a way, measurements created reality as we understand it. Katz, however, says being able to reverse the collapse "tells us that we really can't assume that measurements create reality because it is possible to erase the effects of a measurement and start again."
Now if only I could decypher what Mother Nature is telling us about the nature of Reality.

Is it consistent with the "Many Worlds" interpretation of Quantum Mechanics? Having a do-over before a particular branch of the Multiverse is chosen as the perceived one? I don't know, this is getting beyond my pay grade.

More on Quantum Mechanics and the nature of Reality at a previous post, The Real, the Complex, and the Imaginary.

This means something. But I have no idea what.


Laserlight said...

It doesn't mean there's a redo switch, it just means that one particular quantum collapse isn't the definition of the time arrow. This seems so obvious that I must be either a genius or too clueless even to be bewildered.
(I know which way I would bet on that)

justme said...

I'm having trouble just deciphering what the reporter is trying to tell us about the nature of the experiment. What does it even mean to "weakly measure the particle continuously"? What does it mean to "partially collaps[e] the quantum state"? Is Schrödinger's cat only mostly dead? And what does it mean to "und[o] the damage [they]'d done"--to "erase the effects of a measurement and start again"? How is that different from measuring a particle, then resetting the experiment to its same initial conditions and measuring it again?

I'm sure the result is somehow meaningful, possibly even profound, but even though I took undergraduate quantum physics, I don't have any idea what they're getting at here. I guess I'd need to dig up Jordan's original paper and read it to be able to appreciate this.

Anonymous said...

"beyond my pay grade"

An Obama quote or just a popular phrase?

Jackie said...

Completely OT, but I thought you and your readers might be interested in the bigotted behavior that still reigns in some parts of norhtern Florida.

Battybattybats said...

"Is Schrödinger's cat only mostly dead?"

No, it just means it's got 8 partial collapses left!

^._.^ Meow!

Lloyd Flack said...

I suspect that the way our minds perceive space is a caricature of the real thing. I think what we have to give up is locality of phenomena.

How we perceive space is an internal representation in our minds. Similarly perceived colour only exists in our minds. What is out there is electromagnetic radiation of various wavelengths, not colours. I expect that our perception of space bears a closer relationship to reality than our perception of colour. But I expect that it only covers some aspects of space not all and does not cover some of what we need to visualize quantum phenomena.

Oh, and speaking of colour perception, I wonder if your slightly shifted visual spectrum has anything to do with your metabolic oddities. I would guess that it is due to a slight difference in the cornea and which wavelengths it is transparent to. said...

I'm with Justme on this one:

Weakly reporting a quantum experiment partially collapsed my state of ignorance but after rereading the article I found I was as mystified as ever.