From: "Saved by Windows Internet Explorer 7" Subject: Quantum quirk | News & Events | University of Calgary Date: Thu, 13 Jan 2011 12:02:31 -0700 MIME-Version: 1.0 Content-Type: multipart/related; type="text/html"; boundary="----=_NextPart_000_0069_01CBB319.C1CB6DC0" X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6002.18263 This is a multi-part message in MIME format. ------=_NextPart_000_0069_01CBB319.C1CB6DC0 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Location: http://www.ucalgary.ca/news/utoday/january12-2011/quantumquirk =EF=BB=BF
January 13, 2011 |
Quantum quirk containedBy Leanne Yohemas Researchers at the = University=20 of Calgary, in Canada, collaborating with the University of = Paderborn, in=20 Germany, are working on a way to make quantum networks a reality = and have=20 published their findings in the journal Nature. A similar finding = by a=20 group at the University of Geneva, in Switzerland is reported in = the same=20 issue. =E2=80=9CWe have demonstrated, for the first time, that a = crystal can store=20 information encoded into, what=E2=80=99s called in quantum = mechanics, entangled=20 quantum states of photons,=E2=80=9D says paper co-author Dr. = Wolfgang Tittel of=20 the U of C=E2=80=99s Institute for Quantum Information Science. = =E2=80=9CThis discovery constitutes an important milestone on = the path toward=20 quantum networks, and will hopefully enable building quantum = networks in a=20 few years.=E2=80=9D In current communication networks, information is sent through = pulses=20 of light moving through optical fibre. The information can be = stored on=20 computer hard disks for future use. Quantum networks operate differently than the networks we use = daily.=20 =E2=80=9CWhat we have = is similar but it=20 does not use pulses of light,=E2=80=9D says Tittel, who is a = professor in the U of=20 C=E2=80=99s physics and astronomy department. =E2=80=9CIn quantum = communication, we also=20 have to store and retrieve information. But in our case, the = information=20 is encoded into entangled states of photons.=E2=80=9D In this state, photons are =E2=80=9Centangled,=E2=80=9D and = remain so even when they=20 fly apart. In a way, they communicate with each other even when = they are=20 very far apart. The difficulty is getting them to stay put without = breaking this fragile quantum link. To achieve this task, the researchers used a crystal doped with = rare-earth ions and cooled it to -270 Celsius. At these = temperatures,=20 material properties change and allowed the researchers to store = and=20 retrieve these photons without measurable degradation. An=20 important feature is that this memory device uses almost entirely = standard=20 fabrication technologies. =E2=80=9CThe resulting robustness and = the possibility to=20 integrate the memory with current technology, such as fibre-optic = cables,=20 is important when moving the currently fundamental research = towards=20 applications.=E2=80=9D Quantum networks will allow sending information without being = afraid of=20 somebody listening in. =E2=80=9CThe results show that entanglement, a quantum physical = property that=20 has puzzled philosophers and physicists for hundreds of years, is = not as=20 fragile as is generally believed,=E2=80=9D says Tittel. The article entitled Broadband waveguide quantum memory for entangled =
photons=20
is published in Nature and co-written by Wolfgang Tittel. =
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