Manufacturing quantum computers
-----BEGIN PGP SIGNED MESSAGE----- Hi all, Regarding the quantum cryptography thread: Some people expressed the view that although the idea may be workable, the manufacturing technology was a long way of being able to produce quantum computers. The quantum dot design proposed by Eckert et al for a quantum "factorisation engine" requires 100000 quantum dots (to factorise RSA-129 or similar) which are each about 10nm across to be fairly densly packed onto a chip. I'm not so sure about this being 'a long way off' in terms of materials technology, and I found the following article on WWW which describes some relevant research into this kind of manufacturing at a US army research centre. I found this on the FedWorld (US Govt, http://www.fedworld.gov/ ) pages.... ============================================================ Part of the "unique ARL (Army Research Lab) facilities" page http://info.arl.army.mil/UAFD/uafd.html ============================================================ Ultralithography Center. This facility provides the Army and DoD with a capability that significantly impacts the development of novel ultra-submicron electronic device technology required by next-generation and future military systems. A multi-million-dollar Leica (Philips) EBPG-5HR electron-beam lithography system, which represents the state of the art in ultra-high-resolution device patterning, is housed in a newly constructed clean room. The Leica EBPG-5HR accomplishes lithography by scanning a finely focused beam of high-energy electrons over an electron-sensitive polymer coating applied to the substrate surface. With an electron beam spot size approaching 10 nm, the Leica EBPG-5HR provides an effective solution to the most demanding lithographic applications, including ultra-small (250 angstrom [= 25nm]) electronic and photonic devices. These devices will provide an enabling foundation for next-generation Army electronic and optoelectronic systems. Devices such as sub-100-nm gate length millimeter-wave high-electron- mobility transistors (HEMTs), novel quantum-effect and mesoscopic (phase-preserving) devices, and quantum-well infrared photo-detectors are patterned with this system. The instrument's high acceleration voltage (100kV) provides a unique capability to pattern closely spaced nanometer-scale device features without feature or sample- related distortion. Automated calibration permits the writing of undistorted patterns over the large sample areas required to fabricate many photonic devices and optoelectronic circuits. ======================================================= Well there you go. Perhaps the technology is nearer than we think. Of course this still doesn't answer the noise problem that critics of the proposed technique think will render it all but useless. However I wanted to make the point that we shouldn't be complacent about the materials technology side of things. Tim May makes the point that he is not selling his shares in intel, and that conventional chip technology is not about to be supplanted. The problem with this IMHO is that these are not two completely different technologies we are talking about. The constantly improving techniques being used to cram more and more onto conventional chips are directly applicable to the manufacture of these proposed quantum dot devices. Just my 2 cents Sherry Sheridan C. Mayo | WWW pages include caving, sci fi and RSC, ANU, Australia | crypto pages. NEW: X-files has its own scmayo@rschp2.anu.edu.au | page with gifs/sounds/fanfic etc. Finger for PGP key | http://rschp2.anu.edu.au:8080/local.html -----BEGIN PGP SIGNATURE----- Version: 2.6 iQCVAgUBLo+G9uFu4n6w1qeBAQGVMgP+Kechf44WUe11qnQG5cD3Ybf+NuNc9jjr ajI7ZXYmZgQb1xdhS7ruy+UOo39zBCPxgKOaCahAniKV9vlNOmHB2pqAr8aYoMWt olhDdZdEWSGrLPAvfh4gVa/T8GI9C2NPc7kusIZujlVHnemBbSSz6FW+dJedR/FE oRKvzzW0IHs= =Ub7K -----END PGP SIGNATURE-----
Sherry Mayo writes
Regarding the quantum cryptography thread: Some people expressed the view that although the idea may be workable, the manufacturing technology was a long way of being able to produce quantum computers. The quantum dot design proposed by Eckert et al for a quantum "factorisation engine" requires 100000 quantum dots (to factorise RSA-129 or similar) which are each about 10nm across to be fairly densly packed onto a chip. I'm not so sure about this being 'a long way off' in terms of materials technology,
Current art is fairly close to making components whose interaction requires a full quantum description. To make a quantum computer from such components requires that that the components be orders of magnitude faster and more reversible. Presently known quantum algorithms cannot tolerate the loss of a single quantum of energy, as this will introduce vacuum noise into the data. The longer the algorithm takes, the less energy there is in a single quantum of energy, thus the components for any long quantum algorithm, such as factoring a 1024 bit number, must be very fast indeed (near infrared frequencies) and extraordinarily efficient (fully reversible classical, non quantum computation.) Although quantum computers are interesting and important, they have no immediate practical relevance to cryptography. Error tolerant algorithms could change the picture substantially, but they would still require components far beyond current art. -- --------------------------------------------------------------------- We have the right to defend ourselves and our property, because of the kind of animals that we James A. Donald are. True law derives from this right, not from the arbitrary power of the omnipotent state. jamesd@netcom.com
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Sherry Mayo