Reducing noise in quantum operation at room temperature

first_img One of the obstacles involved in building a quantum memory is that it is difficult to get a true quantum effect due to the decoherence associated with noise, when working at room temperature. “With previous demonstrations in this quantum regime, ultracold atomic gases or cryogenic solid state materials have been used as a storage medium,” Walmsley explains.Walmsley is part of a group working to create room temperature solutions for quantum computing. The group, working out of Clarendon Laboratory at Oxford, includes Klaus Reim, Patrick Michelberger, Ka Chung Lee, Joshua Nunn and Nathan Langford as well as Walmsley. The results of their efforts can be seen in Physical Review Letters: “Single-Photon-Level Quantum Memory at Room Temperature.”“Our breakthrough is two-fold,” Walmsley explains. “Using a so-called Raman interaction allowed a dramatic increase in potential bandwidth. The second advantage is that you can use these warm vapors, allowing quantum operation at room temperature.”In order to make their quantum memory work, Walmsley and his colleagues store information in the collective state of atoms in a warm vapor. “This concept has been around for years, but we are looking at how to make it work practically at room temperature.”The team at Oxford uses a strong off-resonant control pulse to store a weak quantum light pulse. “It’s two step,” he says. “We put in the quantum light with a control pulse. Because their frequencies are tuned out of resonance with the atoms, neither is absorbed without the other. This allows you larger bandwidth.” “Additionally, because neither is absorbed without the other, you don’t have extraneous atoms that have absorbed energy from the control pulse alone, and which can then give away this energy in the form of noise photons,” Walmsley continues. “It’s these extra photons that have added to the noise in previous attempts, and been a deal-breaker for room-temperature quantum memories.” The use of warm atomic cesium vapors show that quantum operation can be achieved in ambient conditions.Walmsley says that, already, their technique offers applications. “Even though the memory isn’t perfect yet, there are some things we can do, like entanglement distillation.” He explains that he thinks that this technique could improve the efficiency of quantum repeaters. “The idea of a quantum repeater has been around for about 12 years now, but without a memory you get a degree of degraded quality so that signals are lost. Theoretically, our system could make quantum repeaters a reality.”Room temperature quantum memory would be a great step forward for quantum communications and quantum information processing. Quantum repeaters might need to be placed in remote areas, or in areas that are warm. Reliable quantum memory will be needed in the coming years as secure quantum communications are in greater demand. Walmsley hopes that his group can be at the forefront of turning the possibilities into realities. “While there are things we can do now, there is still a great deal of room for improvement,” he says. “We want to improve efficiency, and the stability of the memory.” Another important point will be to shrink the technology. “We want to miniaturize it so that it is small enough to integrate into fiber optic networks,” Walmsley continues. “This is a definite breakthrough, but we still have some way to go.” Physicists demonstrate 100-fold speed increase in optical quantum memory Copyright 2011 All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. More information: K.F. Reim, P. Michelberger, K.C. Lee, J. Nunn, N.K. Langford, and I.A. Walmsley, “Single-Photon-Level Quantum Memory at Room Temperature,” Physical Review Letters (2011). Available online: Explore further Citation: Reducing noise in quantum operation at room temperature (2011, August 23) retrieved 18 August 2019 from ( — “A quantum memory is a crucial component of future quantum information processing technologies. Among these technologies, a quantum communications system based on light will enable vastly improved performance over conventional systems, and allow quantum computers to be connected,” Ian Walmsley tells Walmsley is a scientist at the University of Oxford in the United Kingdom. “Building such as system will require a means to effect the temporary storage of single light quanta – photons.”last_img read more

Altius Fortius Citius

first_imgA lady with a decade of experience with television and a zeal for sports has decided to give India a reason to smile. Meet Aparna Apte Gupta, documentary film maker, who has taken on the herculean task of revealing a sparkling side to Indian sports in a documentary called India Sporting Struggle. We call the task at hand a tough one as Gupta herself admits that we Indians have the terrible habit of harping on that that is bad with our country. We talk about crumbling infrastructures, lack of facilities and lack of government initiatives. Especially in the field of sports, we have all debated or heard people complaining about how Indians haven’t bagged enough trophies and medals in international events – we blame the government, we blame the players.  Also Read – ‘Playing Jojo was emotionally exhausting’Gupta points out that there are sports facilities that work on pay-and-use option and no one seems to be using them. These places were created for the recent Commonwealth Games and post the whole hoopla, now lie unused. ‘It is not like the government doesn’t do anything – it is time we accepted that there are shortcomings from our end as well,’ says Gupta. However she does admit that there is obvious scope for the government to up their efforts in this front, but the process must be two-fold.  Also Read – Leslie doing new comedy special with NetflixIndia has a very dismissive attitude towards sports says Gupta. Children are made to choose academics over sports as almost every parent considers sports to be a waste of time. Only in rare cases would people find parents encouraging kids to pursue a sport seriously. And then again cricket, tennis and now badminton get the thumbs-up while athletics, basketball, hockey, football, et all lie ignored. It is all about where the glamour lies and little glory.  Gupta blames the lack of awareness for this phenomenon, ‘Most people are not aware of sports that can offer ample chances to flourish. The motivation and the will is lacking because no one knows enough,’ she says. To turn the tide, Gupta has picked three child prodigies from the country. Shubham Jaglan (8) a milkman’s son is currently playing three Golf tournaments back to back in the USA. He has already won the World Championship. He’s currently playing the U.S. Kids Championship. Bipasha Mukherjee (14) is autistic. This January, Bipasha brought back a gold and a silver medal in Ice Speed Skating at the World Paralympics held in Korea. Bipasha’s parents have dealt with taunts from family members who value education more than anything else, says Gupta.  Prayag Chauhan (15) from Haryana, an automobile dealer’s son is a  boxer. Prayag’s parents pushed him and his brother into sports. Their parents have a passion for sports but struggled to deal with school authorities and family members who taunted them for ‘misleading’ their children. Even neighbours gossiped when Prayag’s mother learnt to drive so she could drive both the boys to training and back – such is India. Bringing their stories to the forefront will hopefully make people sit up and pay attention, explains Gupta. While her documentary is not necessarily a pro-government discourse, there are problems that the government must acknowledge and deal with – it is more about creating an awareness and trying to read the larger issue in Indian society which prohibits us from utilising real potential.last_img read more