There are 3 messages in this issue.
Topics in this digest:
1. Spin Triplets - Nano-scale metric engineering with self-assembly?
From: "Berkant"
2. Spin Triplets - Spintronics - Nano-scale metric engineering with self-assembly?
From: "Berkant"
3. Re: Multiple Universes and Creation; Big Bang Goes Bust? NO!
From: Jack Sarfatti
Good.
Message: 1
Date: Sun, 20 Jun 2004 19:00:41 -0000
From: "Berkant"
Subject: Spin Triplets - Nano-scale metric engineering with self-assembly?
Jack wrote that we need spin triplets.. Terry mentioned nanotube
quantum dots..
Let's look for "spin triplets" nanotubes in google:
7 items..
PDF] Towards Quantum Communication with Electron
SpinsDateiformat: ... a noise measurement can distinguish spin-
singlet states from spin-triplets by probing ... superconductivity
was found in ropes of single-walled carbon nanotubes [39 ...
http://journals.tubitak.gov.tr/physics/ issues/fiz-03-27-5/fiz-27-5-
10-0309-3.pdf
[PDF] Creation of Nonlocal Spin-Entangled Electrons via Andreev
.... by strong correlations in one-dimensional leads (such as
nanotubes) with Luttinger ... whereas the noise is suppressed in the
case of spin triplets because of ...
http://www.kluweronline.com/article.asp?PIPS=367297&PDF=1
[PDF] arXiv:cond-mat/0205484 v1 23 May ... correlations in one-
dimensional leads (such as nanotubes) with Luttinger liquid
properties. ... whereas the noise is suppressed in the case of spin
triplets due to ...
http://arxiv.org/pdf/cond-mat/0205484
[PDF] arXiv:cond-mat/0009452 v2 13 Oct 2000Dateiformat: PDF/Adobe
Acrobat - HTML-Version
.... to bunching behavior, whereas the noise is suppressed for spin-
triplets leading to ... Other candidate materials are eg carbon
nanotubes which also show Coulomb ...
http://arxiv.org/pdf/cond-mat/0009452
[PDF] THE GENERATION AND DETECTION OF ELECTRON
ENTANGLEMENTDateiformat: PDF/Adobe Acrobat - HTML-Version
.... Kim on numerous experimental and theoreti- cal issues, including
the very exciting observation of noise suppression in single-walled
Carbon nanotubes with our ...
http://marcuslab.harvard.edu/theses/ othertheses/Oliver_Thesis.pdf
[PDF] Few-electron quantum dots
Page 1. I NSTITUTE OF P HYSICS P UBLISHING R EPORTS ON P ROGRESS IN
P HYSICS Rep. Prog. Phys. 64 (2001) 701–736 www.iop.org/Journals ...
http://qt.tn.tudelft.nl/publi/Leok/IOPLeok01-dreamteam.pdf
Phys. Rev. B 63, 165314 (2001): Recher et al. - Andreev
tunneling ...... bunching behavior, whereas the noise is suppressed
for spin triplets leading toantibunching ... 19 Other candidate
materials are, eg, carbon nanotubes, which also ...
http://dx.doi.org/10.1103/PhysRevB.63.165314
--- In SarfattiScienceSeminars@yahoogroups.com, Jack Sarfatti
The team considered nanotori with various radii, made from
different
types of metallic nanotube, known as 'armchair' or 'zigzag'. In
their
calculations, the researchers assume that the nanotori are in a
magnetic field of 0.1 tesla, which causes the spins of the
electrons
to line up, producing a magnetic moment. They also imagined that
the
electrons were flowing around the rings as an electrical current.
Problem with Cooper pairs are that they are spin singlets. We
would
need spin triplets.
________________________________________________________________________
Message: 2
Date: Sun, 20 Jun 2004 19:18:41 -0000
From: "Berkant"
Subject: Spin Triplets - Spintronics - Nano-scale metric engineering with self-assembly?
Yesterday, I started reading the Corso book.. in the introduction we
can read: "And this is not to mention the military fears at first
that the craft might have been an experimental Soviet weapon because
it bore a resemblance to some of the German-designed aircraft that
had made their appearances near the end of the war, especially the
crescent-shaped Horton flying wing..."
I will soon upload some of results related to my intuitive Fibonacci
flying wing design.. see at http://www.future-workshop.com
Interesting, the first search item of the search function "spin
triplets" nanotubes shows a spintronics link to the
TURKISH JOURNAL OF PHYSICS
http://journals.tubitak.gov.tr/physics/
-->
SARAGA sounds like a Turkish name...
http://journals.tubitak.gov.tr/physics/issues/fiz-03-27-5/fiz-27-5-
10-0309-3.pdf
Towards Quantum Communication with Electron Spins
D.S. SARAGA1, G. BURKARD2, J. C. EGUES3, H.-A. ENGEL1,
P. RECHER1, D. LOSS1
1Department of Physics and Astronomy, University of Basel
Klingelbergstrasse 82, 4056 Basel, Switzerland
2IBM T. J. Watson Research Center, P. O. Box 218, Yorktown Heights,
NY 10598
3Department of Physics and Informatics, University of S~ao Paulo at
S~ao Carlos, 13560-970 S~ao Carlos/SP, Brazil
in Turk J Phys 27 (2003) , 427 - 441.
We review our recent work towards quantum communication in a solid-
state environment with qubits carried by electron spins. We propose
three schemes to produce spin-entangled electrons, where the
required separation of the partner electrons is achieved via Coulomb
interaction. The non-product spinstates originate either from the
Cooper pairs found in a superconductor, or in the ground state of a
quantum dot with an even number of electrons. In a second stage, we
show how spin-entanglement carried by a singlet can be detected in a
beam-splitter geometry by an increased (bunching) or decreased
(antibunching) noise signal. We also discuss how a local spin-orbit
interaction can be used to provide a continuous modulation of the
noise as a signature of entanglement. Finally, we review how one can
use a quantum dot as a spin-filter, a spin-memory read-out, a probe
for single-spin decoherence and, ultimately, a single-spin
measurement apparatus.
Yes, this looks good. A step in the right direction. I thought of qualitative idea of spintronics for quantum computing quite independently in late 1970's and it was very much part of Harold Chipman's plan in 1984 as shown in documents in "Destiny Matrix." It's actually an obvious idea, but it took awhile to become "mainstream" and "respectable."
Note, that spintronics may well involve the Soviet torsion fields, if Nature allows them. Nature should allow them since they have the same origin as Einstein's gravity, i.e. local gauge invariance principle applied to the space-time symmetries of the conformal group. This demands additional gauge force fields, i.e.
1. Einstein's 1916 gravity from locally gauging the 4-parameter translation group infinitesimally generated by total Energy-Momentum Pu
2. Soviet (Shipov/Akimov) torsion fields from locally gauging the 6-parameter Lorentz group infinitesimally generated by 3 total angular momenta J = L + S for space-space rotations and 3 Lorentz boosts for mixed space-time rotations.
3. A local gauge force field from the 4 special conformal transformations to uniformly accelerated "hyperbolic" special relativistic rocket motion.
4. A local gauge force field from 1 dilation, which seems to be linked to Bohm's quantum potential.
guv(x) ---> g'uv(x) = D(x)guv(x)
The idea here is simple. Use the local gauge invariance principle for ALL continuous symmetries both internal and space-time.
The issue of the strength of the coupling constants - generally not constants at all, but scale-dependent variables is largely an empirical matter. See "renormalization group flows to fixed points."
1. Introduction
The goal of the growing field of spintronics [1, 2] is to harness the
spin degree-of-freedom of the electron in a solid-state environment.
By going beyond the manipulation of the electron charge found in
standard electronics, one pursues the development of new devices
that use specifically the electron spin: for instance, magnetic read-
out heads for computer hard drives, single-spin memories, or spin
transistors [3, 4]. One ingredient is the injection and detection of
spin-polarized currents, which has now been studied experimentally
with various approaches [5, 6, 7]. A more ambitious step is to
consider quantum computation [8], for which it has been proposed to
use the electron spin as a qubit [9]. This naturally requires
coherent manipulation of the quantum spin-state, which is limited by
decoherence. The issue of electron spin decoherence in semiconductors
has found positive support from a number of experiments, which have
now demonstrated long decoherence times (exceeding 100 ns) for
electron spins in bulk n-doped GaAs, as well as coherent transport
of spins over distances up to 100 m [11]. In this work, we address
the most fundamental issues concerning the use of the electron spin
in quantum communication [10], the basic resource being Einstein-
Podolsky-Rosen (EPR) pairs [12]. Here the motivation stems from for
the desire to use the same physical qubit as the one used for
quantum computation [9], in order to have "on-chip" quantum
communication without transfers to photonic states. Secondly, these
e orts open the path towards experimental tests of quantum
non-locality with massive particles in the solid state (via
violation of Bell's inequality [13]).
....
5. Conclusion
We have proposed and theoretically analyzed devices which address a
number of milestones of quantum communication protocols with
electron spins in mesoscopic systems. For the creation of EPR-pairs,
we have proposed three di erent schemes for the preparation of spin-
singlet electron pairs, and their injection into solid-state quantum
channels. In the second part, we have discussed an interference
device able to distinguish, via noise measurement, the entangled
spin singlet from the spin triplet states. A local spin-orbit
interaction extends this proposal by allowing a continuously
variable noise signature, controllable by external gates.
Finally, we have shown how one can use single quantum dots as
fundamental tools for accessing quantum information stored as a
single spin. We have described a spin-lter, a spin-memory read-out,
and, finally, a device able to estimate the decoherence rate of a
single-spin in a quantum dot |a crucial parameter for the coherent
manipulation of the fundamental quantum system that is an electron
spin.
Acknowledgments
We would like to thank E.V. Sukhorukov for his contribution to the
work presented here. Financial support from NCCR "Nanoscale
Science", Swiss NSF, U.S. DARPA and ARO is gratefully acknowledged.
________________________________________________________________________
Message: 3
Date: Mon, 21 Jun 2004 11:23:22 -0700
From: Jack Sarfatti
Subject: Re: Multiple Universes and Creation; Big Bang Goes Bust? NO!
On Jun 21, 2004, at 9:34 AM, michael ibison wrote:
HI Victor
That I don't embrace BB is an accurate description. I do not hold a
strong
view on whether or not the currently accepted view is correct. That
makes me
a radical. Not because I say it is wrong, but because I am an agnostic.
Cheers,
Michael
That's only because you have not kept up with advances in the field. I
agree that prior to say end of 2002 the position held in that May 22,
2004 New Scientist Letter was slightly plausible and defensible as a
long shot - but no longer. Without applying a double standard, the
Baysean probability that the standard model with chaotic inflation,
dark energy/matter is essentially correct is very close to 100% and
getting closer all the time as new data comes in. What we have here is
a debate on how to weigh the new data that you admit you are not very
up on. I have been to 2 APS meetings on this topic in 2003 and listened
closely to Mike Turner and Saul Perlmutter - the experimental work is
beautiful - some of the best in the history of physics. This is a real
turning point. It also explains the saucers, the emergence of
Einstein's gravity from the cohering of random noise ZPF not from its
friction, the stability of electrically charged elementary particles as
spatially extended structures that shrink when hit hard, the stability
of the galaxy, the universal Regge slope, Ken Shoulders' charge
clusters, the Arrow of Time and even the emergence of consciousness in
the many worlds. What more do you want? This is grand!
Strong prediction that can falsify my idea: Dark matter detectors
cannot click, in principle, with the right stuff to explain Omega(DM) ~
0.23 any more than the motion of the Earth through the Galilean ether
can be detected with a Michelson-Morley interferometer in the domain of
validity of special relativity where the scale of the relative phase
measurements are small compared to the radius of curvature that the Sun
makes at the position of the Earth in its orbit.
PS How do Marshall Trevor/Haisch, Puthoff, Rueda, Cole et-al explain
observed sub-Poisson statistics of photon anti-bunching in laser light
which requires negative probability if you use SED?
No comments:
Post a Comment