| Topic: |
Science > Physics |
| User: |
"Sam Wormley" |
| Date: |
10 Nov 2006 07:42:02 PM |
| Object: |
Spin measured without destruction |
Spin measured without destruction
http://physicsweb.org/articles/news/10/11/10/1
10 November 2006
The spin state of a single electron in a quantum dot has been
measured for the first time without destroying the state. David
Awschalom and colleagues at University of California, Santa Barbara,
determined the spin by reflecting polarized laser light from a
quantum dot. The development could lead to the exploitation of the
quantum properties of single electrons in quantum computers
(Sciencexpress 9 November 2006).
Quantum computers could exploit the fact that a quantum particle can
be in two states at the same time -- spin up or spin down in the case
of an electron. With the two states representing a one or a zero, N
such particles -- or quantum bits (qubits) -- could be combined or
"entangled" to represent 2^n values simultaneously. This could lead to
the parallel processing of information on a massive scale. However,
the realization of a quantum computer involves fundamental challenges
such as how to read the logical state of a qubit without destroying
the state, and how to entangle the qubits.
See: http://physicsweb.org/articles/news/10/11/10/1
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| User: "Jan Panteltje" |
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| Title: Re: Spin measured without destruction |
11 Nov 2006 07:15:59 AM |
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On a sunny day (Sat, 11 Nov 2006 01:42:02 GMT) it happened Sam Wormley
<swormley1@mchsi.com> wrote in <KT95h.231406$FQ1.144417@attbi_s71>:
Spin measured without destruction
http://physicsweb.org/articles/news/10/11/10/1
10 November 2006
The spin state of a single electron in a quantum dot has been
measured for the first time without destroying the state.
End of quantum security?
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| User: "Ben Rudiak-Gould" |
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| Title: Re: Spin measured without destruction |
11 Nov 2006 08:54:08 AM |
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Jan Panteltje wrote:
Sam Wormley wrote:
The spin state of a single electron in a quantum dot has been
measured for the first time without destroying the state.
End of quantum security?
If you mean quantum cryptography, no, this doesn't threaten it.
-- Ben
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| User: "Jan Panteltje" |
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| Title: Re: Spin measured without destruction |
11 Nov 2006 09:28:10 AM |
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On a sunny day (Sat, 11 Nov 2006 14:54:08 +0000) it happened Ben Rudiak-Gould
<br276deleteme@cam.ac.uk> wrote in <ej4o6g$hf2$1@gemini.csx.cam.ac.uk>:
Jan Panteltje wrote:
Sam Wormley wrote:
The spin state of a single electron in a quantum dot has been
measured for the first time without destroying the state.
End of quantum security?
If you mean quantum cryptography, no, this doesn't threaten it.
OK, yes, but quantum crypt is not secure at all anyways ;-).
And highly impractical to make a fiber connection from everybody to everybody
else in case of single photon polarised light transmisisons.
No way.
And single photon no way either it seems.
OK it is Saturday, I plead no contest.
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| User: "malibu" |
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| Title: Re: Spin measured without destruction |
10 Nov 2006 09:49:04 PM |
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Sam Wormley wrote:
Spin measured without destruction
http://physicsweb.org/articles/news/10/11/10/1
10 November 2006
The spin state of a single electron in a quantum dot has been
measured for the first time without destroying the state. David
Awschalom and colleagues at University of California, Santa Barbara,
determined the spin by reflecting polarized laser light from a
quantum dot. The development could lead to the exploitation of the
quantum properties of single electrons in quantum computers
(Sciencexpress 9 November 2006).
Quantum computers could exploit the fact that a quantum particle can
be in two states at the same time -- spin up or spin down in the case
of an electron. With the two states representing a one or a zero, N
such particles -- or quantum bits (qubits) -- could be combined or
"entangled" to represent 2^n values simultaneously. This could lead to
the parallel processing of information on a massive scale. However,
the realization of a quantum computer involves fundamental challenges
such as how to read the logical state of a qubit without destroying
the state, and how to entangle the qubits.
you're drunk
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| User: "Sam Wormley" |
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| Title: Re: Spin measured without destruction |
10 Nov 2006 09:58:33 PM |
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malibu wrote:
Sam Wormley wrote:
Spin measured without destruction
http://physicsweb.org/articles/news/10/11/10/1
10 November 2006
The spin state of a single electron in a quantum dot has been
measured for the first time without destroying the state. David
Awschalom and colleagues at University of California, Santa Barbara,
determined the spin by reflecting polarized laser light from a
quantum dot. The development could lead to the exploitation of the
quantum properties of single electrons in quantum computers
(Sciencexpress 9 November 2006).
Quantum computers could exploit the fact that a quantum particle can
be in two states at the same time -- spin up or spin down in the case
of an electron. With the two states representing a one or a zero, N
such particles -- or quantum bits (qubits) -- could be combined or
"entangled" to represent 2^n values simultaneously. This could lead to
the parallel processing of information on a massive scale. However,
the realization of a quantum computer involves fundamental challenges
such as how to read the logical state of a qubit without destroying
the state, and how to entangle the qubits.
you're drunk
I had but one glass of wine tonight! Quantum computers are down the
road a bit, but coming along quicker than I once imagined, John.
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| User: "" |
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| Title: Re: Spin measured without destruction |
10 Nov 2006 10:25:03 PM |
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Sam Wormley <swormley1@mchsi.com> wrote:
malibu wrote:
Sam Wormley wrote:
Spin measured without destruction
http://physicsweb.org/articles/news/10/11/10/1
10 November 2006
The spin state of a single electron in a quantum dot has been
measured for the first time without destroying the state. David
Awschalom and colleagues at University of California, Santa Barbara,
determined the spin by reflecting polarized laser light from a
quantum dot. The development could lead to the exploitation of the
quantum properties of single electrons in quantum computers
(Sciencexpress 9 November 2006).
Quantum computers could exploit the fact that a quantum particle can
be in two states at the same time -- spin up or spin down in the case
of an electron. With the two states representing a one or a zero, N
such particles -- or quantum bits (qubits) -- could be combined or
"entangled" to represent 2^n values simultaneously. This could lead to
the parallel processing of information on a massive scale. However,
the realization of a quantum computer involves fundamental challenges
such as how to read the logical state of a qubit without destroying
the state, and how to entangle the qubits.
you're drunk
I had but one glass of wine tonight! Quantum computers are down the
road a bit, but coming along quicker than I once imagined, John.
Yep, just around the corner along with artificial intelligence, fusion
power, a cure for the common cold, world peace now that we have the
UN instead of that wimpy League of Nations, a hit movie starring
Vanna White, and something without calories that actually tastes good.
--
Jim Pennino
Remove .spam.sux to reply.
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| User: "FrediFizzx" |
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| Title: Re: Spin measured without destruction |
11 Nov 2006 02:36:39 AM |
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<jimp@specsol.spam.sux.com> wrote in message
news:jkvf24-td2.ln1@mail.specsol.com...
Sam Wormley <swormley1@mchsi.com> wrote:
malibu wrote:
Sam Wormley wrote:
Spin measured without destruction
http://physicsweb.org/articles/news/10/11/10/1
10 November 2006
The spin state of a single electron in a quantum dot has been
measured for the first time without destroying the state. David
Awschalom and colleagues at University of California, Santa
Barbara,
determined the spin by reflecting polarized laser light from a
quantum dot. The development could lead to the exploitation of
the
quantum properties of single electrons in quantum computers
(Sciencexpress 9 November 2006).
Quantum computers could exploit the fact that a quantum
particle can
be in two states at the same time -- spin up or spin down in
the case
of an electron. With the two states representing a one or a
zero, N
such particles -- or quantum bits (qubits) -- could be combined
or
"entangled" to represent 2^n values simultaneously. This could
lead to
the parallel processing of information on a massive scale.
However,
the realization of a quantum computer involves fundamental
challenges
such as how to read the logical state of a qubit without
destroying
the state, and how to entangle the qubits.
you're drunk
I had but one glass of wine tonight! Quantum computers are down
the
road a bit, but coming along quicker than I once imagined, John.
Yep, just around the corner along with artificial intelligence, fusion
power, a cure for the common cold, world peace now that we have the
UN instead of that wimpy League of Nations, a hit movie starring
Vanna White, and something without calories that actually tastes good.
Ice water tastes pretty good when you are really thirsty. ;-) Just
tried some right now. Pretty good for calorie free stuff.
Yeah, what up with Vanna White?
FrediFizzx
Quantum Vacuum Charge papers;
http://www.vacuum-physics.com/QVC/quantum_vacuum_charge.pdf
or postscript
http://www.vacuum-physics.com/QVC/quantum_vacuum_charge.ps
http://www.arxiv.org/abs/physics/0601110
http://www.vacuum-physics.com
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| User: "Edward Green" |
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| Title: Re: Spin measured without destruction |
11 Nov 2006 05:22:03 PM |
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wrote:
Yep, just around the corner along with artificial intelligence, fusion
power, a cure for the common cold, world peace now that we have the
UN instead of that wimpy League of Nations, a hit movie starring
Vanna White, and something without calories that actually tastes good.
Spring water, and Fresca (though the last may be an acquired taste).
World peace and freedom are, I regret, incompatible concepts. The best
that can be hoped for is a kind of Pax Romana, a benign dictatorship
.... like the one exercised by the nanny in the nursery who takes away
the freedom of the poor tykes to kill each other, which not only crimps
their freedom, but is probably also censorship and a form of child
abuse.
I can't see why, given the explosion of processing power available,
something like AI hasn't been developed the old fashioned way --
through evolution. We merely need a sea of bits large enough, and...
maybe to get things started a model of genetic code... and let the
autonomous programs sort it out among themselves. From time to time we
could up the hostility of the environment, and add the occasional mass
extinction.
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| User: "Ken Muldrew" |
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| Title: Re: Spin measured without destruction |
13 Nov 2006 01:27:45 PM |
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"Edward Green" <spamspamspam3@netzero.com> wrote:
Spring water, and Fresca (though the last may be an acquired taste).
Have you ever noticed the precipitate that forms when you mix Fresca
with Ouzo? (If not, then try it and report back).
Ken Muldrew
kmuldrezw@ucalgazry.ca
(remove all letters after y in the alphabet)
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| User: "Timo A. Nieminen" |
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| Title: Re: Spin measured without destruction |
13 Nov 2006 01:56:58 PM |
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On Mon, 13 Nov 2006, Ken Muldrew wrote:
"Edward Green" <spamspamspam3@netzero.com> wrote:
Spring water, and Fresca (though the last may be an acquired taste).
Have you ever noticed the precipitate that forms when you mix Fresca
with Ouzo? (If not, then try it and report back).
This differs from the usual outcome of ouzo + water? Is so, how so? Given
that we're interested in approximately wavelength-sized particles, perhaps
we could try playing with some ouzo? Imagine, trying to get a bottle of
ouzo through the finance people! There was something in the news many
years ago, with a Russian group getting vodka to work as a lasing medium.
Perhaps a similar idea?
--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
E-prints: http://eprint.uq.edu.au/view/person/Nieminen,_Timo_A..html
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html
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| User: "Ken Muldrew" |
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| Title: Re: Spin measured without destruction |
14 Nov 2006 01:36:28 PM |
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"Timo A. Nieminen" <timo@physics.uq.edu.au> wrote:
On Mon, 13 Nov 2006, Ken Muldrew wrote:
"Edward Green" <spamspamspam3@netzero.com> wrote:
Spring water, and Fresca (though the last may be an acquired taste).
Have you ever noticed the precipitate that forms when you mix Fresca
with Ouzo? (If not, then try it and report back).
This differs from the usual outcome of ouzo + water?
That is my recollection, but it was a long time ago and the ouzo was
overproof and the bottle was emptied and so may have affected said
recollection, etc., etc.
If so, how so?
In fact, now that some flecks of memory are returning, it was even
different from Fresca and Sambuca. Only the Ouzo produced a
precipitate.
Given
that we're interested in approximately wavelength-sized particles, perhaps
we could try playing with some ouzo? Imagine, trying to get a bottle of
ouzo through the finance people!
All it takes is some preliminary data, then they can't refuse!
There was something in the news many
years ago, with a Russian group getting vodka to work as a lasing medium.
I can picture several scenarios where a Russian group might try this,
but to actually have it work! Serendipity, for sure.
Ken Muldrew
kmuldrezw@ucalgazry.ca
(remove all letters after y in the alphabet)
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| User: "Edward Green" |
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| Title: Re: Spin measured without destruction |
13 Nov 2006 08:12:44 PM |
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Timo A. Nieminen wrote:
On Mon, 13 Nov 2006, Ken Muldrew wrote:
"Edward Green" <spamspamspam3@netzero.com> wrote:
Spring water, and Fresca (though the last may be an acquired taste).
Have you ever noticed the precipitate that forms when you mix Fresca
with Ouzo? (If not, then try it and report back).
This differs from the usual outcome of ouzo + water? Is so, how so?
I take it ouzo is full of dissolved crud, decreasingly soluble in
ethanol/water solutions as the proportion of ethanol decreases.
I hope that mixing ouzo with Fresca is not a waste of good ouzo. On
the other hand, I should talk: I once mixed 22 year old Scotch with
diet ginger ale ... there was nobody around to drink the Scotch with,
and it was tasty. In fact, it was the most complex, peaty, ginger ale
I have ever tasted. I probably should have started with crushed fresh
ginger, seltzer water, and powedered sugar, however: that would have
lent the thing the pseudo-refined foody elan of using fresh
ingredients, and I could have called it "shandygaff".
Given
that we're interested in approximately wavelength-sized particles, perhaps
we could try playing with some ouzo? Imagine, trying to get a bottle of
ouzo through the finance people! There was something in the news many
years ago, with a Russian group getting vodka to work as a lasing medium.
Perhaps a similar idea?
Sound like great fun. Idea for forbidden science themed party: listen
to music via oxy-acetylene flame speaker, light effects provided by
vodka laser. Drink lasing medium. Inhale oxygen. Wonder what
acetylene smells like ... nobody light a match!
"I wish I had a barrel of rum, and sugar 300 lbs.
A college bell to mix it in, the clapper to stir it round".
And etc...
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| User: "Ken Muldrew" |
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| Title: Re: Spin measured without destruction |
14 Nov 2006 01:44:16 PM |
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"Edward Green" <spamspamspam3@netzero.com> wrote:
I hope that mixing ouzo with Fresca is not a waste of good ouzo.
If it's full of barely dissolved crud, then perhaps this is a
necessary step in refining the product. Besides, it was the only time
I remember finding a good use for Fresca.
On
the other hand, I should talk: I once mixed 22 year old Scotch with
diet ginger ale ... there was nobody around to drink the Scotch with,
and it was tasty. In fact, it was the most complex, peaty, ginger ale
I have ever tasted.
The only question is whether an inferior Scotch would have tasted as
good. And if so, then you, sir, are a savage.
I probably should have started with crushed fresh
ginger, seltzer water, and powedered sugar, however: that would have
lent the thing the pseudo-refined foody elan of using fresh
ingredients, and I could have called it "shandygaff".
The veneer of civilization is wafer thin; at least you are able to
recognize how your betters would have acted even if you lack the moral
fortitude to restrain your primitive desires.
Ken Muldrew
kmuldrezw@ucalgazry.ca
(remove all letters after y in the alphabet)
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| User: "Edward Green" |
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| Title: Re: Spin measured without destruction |
14 Nov 2006 08:35:15 PM |
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Ken Muldrew wrote:
"Edward Green" <spamspamspam3@netzero.com> wrote:
On
the other hand, I should talk: I once mixed 22 year old Scotch with
diet ginger ale ... there was nobody around to drink the Scotch with,
and it was tasty. In fact, it was the most complex, peaty, ginger ale
I have ever tasted.
The only question is whether an inferior Scotch would have tasted as
good. And if so, then you, sir, are a savage.
Indeed... the empty bottle is a silent reproach to me even today.
But one thing is sure: drink it neat, drink it with water, drink it
with diet ginger ale, or drink it with Fresca; you can't have your
Scotch, and drink it too.
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| User: "" |
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| Title: Re: Spin measured without destruction |
12 Nov 2006 08:45:42 AM |
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In article <1163287322.964342.114520@m7g2000cwm.googlegroups.com>,
"Edward Green" <spamspamspam3@netzero.com> wrote:
jimp@specsol.spam.sux.com wrote:
Yep, just around the corner along with artificial intelligence, fusion
power, a cure for the common cold, world peace now that we have the
UN instead of that wimpy League of Nations, a hit movie starring
Vanna White, and something without calories that actually tastes good.
Spring water, and Fresca (though the last may be an acquired taste).
World peace and freedom are, I regret, incompatible concepts. The best
that can be hoped for is a kind of Pax Romana, a benign dictatorship
.... like the one exercised by the nanny in the nursery who takes away
the freedom of the poor tykes to kill each other, which not only crimps
their freedom, but is probably also censorship and a form of child
abuse.
I can't see why, given the explosion of processing power available,
something like AI hasn't been developed the old fashioned way --
through evolution.
Because people keep interfering ;-)
We merely need a sea of bits large enough, and...
maybe to get things started a model of genetic code... and let the
autonomous programs sort it out among themselves. From time to time we
could up the hostility of the environment, and add the occasional mass
extinction.
That game has already been written and distributed.
/BAH
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