Month: August 2019

  • Researchers use light projector and singlepixel detectors to create 3D images

    first_img(Phys.org) —Researchers from the University of Glasgow and the University of Cambridge have devised a unique method of capturing three-dimensional images. As described in a paper published in the journal Science, they used an ordinary light projector, four single-pixel photodetectors, an analog-to-digital converter, and a computer to capture 3-D images of a mannequin head. Single-pixel power: Scientists make 3-D images without a camera More information: Science 17 May 2013: Vol. 340 no. 6134 pp. 844-847 DOI: 10.1126/science.1234454 The idea is based on the concept of ghost imaging where paired light sources, such as a split laser beam, are used to create 3-D images. Prior efforts have involved shooting a target with one part of the split beam, then capturing the reflected light with a photodetector. The other part of the beam is recorded by a traditional camera. In this new effort, the researchers took a much more pragmatic approach—they accomplished the same thing using simpler equipment.To create the 3-D image, the researchers set up a light projector—the same kind used for viewing slides on a screen—with the light projected onto a mannequin head. Next, they placed a transparent screen capable of displaying light-blocking speckle patterns (generated by the computer) between the projector and the mannequin head. Light able to pass through the speckle pattern would eventually strike the mannequin and bounce off. Four single-pixel photodetectors were set up to capture the bounced light—one each above, below and to each side of the projector. The photodectectors were connected to an analog-to-digital converter which sent results to the computer. Once everything was in place, the researchers caused the computer to send different speckle patterns to the screen while the photodetectors captured the reflected light. Each pass allowed the computer to capture more information. As the total number of speckle patterns reached a million, individual 2-D images emerged—each one based on data from a single photodetector. Software on the computer then used the four 2-D images to create a single 3-D image. How such a system might be used is still up for debate, as some issues still need to be worked out. The slow refresh rate, for example, means it takes half an hour to create one image. The researchers are confident they can refine the design, however, to speed up the process. Once that happens, they suggest, their imaging system might be useful for detecting gas fields, building medical systems or catching terrorists at airports.Original press release. Journal information: Science Citation: Researchers use light projector and single-pixel detectors to create 3-D images (2013, May 17) retrieved 18 August 2019 from https://phys.org/news/2013-05-projector-single-pixel-detectors-d-images.html Explore further © 2013 Phys.org 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.last_img read more

  • Using quantum measurements to fuel a cooling engine

    first_img 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. Journal information: Physical Review Letters Michele Campisi, one of the researchers involved in the study, has been studying quantum phenomena for several years. In his recent work, he investigated whether quantum phenomena can impact the thermodynamics of nanoscopic devices, such as those employed in quantum computers. “Most colleagues in the field were looking at coherence and entanglement while only few were looking at another at genuine quantum phenomenon, i.e., the quantum measurement process,” Campisi told Phys.org. “Those studies suggested that you need to accompany measurements with feedback control, as in Maxwell’s demon, in order to exploit their potential. I started thinking about it, and eureka—since quantum measurements are very invasive, they are accompanied by energy exchanges, hence can be used to power engines without the need to do feedback control.”The second law of thermodynamics states that heat naturally flows from hot bodies to cold ones. Past studies found that there are two ways to reverse this natural flow of heat: using work supplied by an external, time-dependent driving force or by implementing a Maxwell demon, which steers the heat via a feedback control loop. In their study, Campisi and his colleagues showed that there is, in fact, a third method to reverse the flow of heat, which is based on quantum mechanics. This technique entails the use invasive quantum measurements as a fuel that powers refrigeration, without any feedback control. The researchers refer to this mechanism as quantum measurement cooling (QMC). “The general mathematical framework is standard quantum mechanics, but we had to use a mix of advanced numerical and analytical methods to investigate all facets of quantum measurement cooling,” Lorenzo Buffoni, another researcher involved in the study, told Phys.org. “For example, in order to assess its the robustness to experimental noise we used extensive Monte Carlo sampling of the high-dimensional space of possible measurement projectors, and used machine learning techniques to analyze and visualize the data.” Citation: Using quantum measurements to fuel a cooling engine (2019, March 11) retrieved 18 August 2019 from https://phys.org/news/2019-03-quantum-fuel-cooling.html Campisi and his colleagues illustrated QMC by means of a prototypical two-stroke two-qubit engine. This engine interacts with the measurement apparatus employed by the researchers, as well as with two heat reservoirs set at different temperatures.”We also embarked on the task of finding the optimal thermodynamic performance by analytical methods, which was very challenging,” Andrea Sofanelli, another researcher who carried out the study, told Phys.org. “We employed Birkhoff theorem to express the so-called transition matrix (containing all relevant information about the energy exchanges in our problem) in terms of permutations, which simplified the problem. But we remained stuck with that until we found a little-known theorem of linear algebra dating back to the early 1990s, which finally led to the solution.”Campisi, Buffoni, Cuccoli, Solfanelli and their colleague Paola Verrucchi demonstrated that the invasiveness of quantum measurements can be used to fuel a cooling engine via the QMC mechanism they have reported. QMC does not require feedback control, but entanglement must be present in the measurement projectors. The researchers calculated the probability that QMC will occur when the measurement basis is randomly selected. They found that this probability can be very large compared to the probability of extracting energy (i.e. operating the heat engine), yet it is smaller than the probability of the least important operation (i.e. dumping heat in both baths). “Showing that measuring a quantum system made by two qubits can produce by itself (i.e. without feedback control) useful thermodynamic effects surely represents the most meaningful outcome of our research,” Alessandro Cuccoli, another researcher involved in the study, told Phys.org. “This follows from looking at the quantum measurement process from a wider perspective, where both the system and its environment, and the energy exchanges accompanying the measurement, are considered.”According to Cuccoli, the two-quibits thermal engine developed by the researchers could easily be engineered to work as a cooling device. This would, among other things, enable the fabrication of a quantum computer’s processing units to be integrated with auxiliary devices that can keep them at the required low temperature, as both can be achieved using qubits. “A further insightful observation is that in order to get useful thermodynamic effects, the measurement process has to involve ‘entangled’ states, i.e. peculiarly quantum correlated states of the two qubits, thus revealing the intimate connection between information and energy exchanges,” Cuccoli added. “Deepening our understanding of such relationship in nanoscopic quantum engines is one of the major challenges driving our current and future research in the field of quantum thermodynamics.”The study carried out by Campisi, Buffoni, Cuccoli, Solfanelli and Verrucchi introduced an entirely new mechanism that can reverse the natural flow of heat, intervening with the second law of thermodynamics, without feedback control requirements. In the future, their findings could have many applications, for instance, aiding the development of devices to cool quantum computers. The team of researchers involved in this study is part of a collaboration consortium that involves 12 world-class research groups, including experimentalists and theorists from eight E.U. countries. They are currently seeking the resources necessary to support their work in the forthcoming years. “We are looking forward to collaborating with experimental groups that might be interested in building a functioning quantum-measurement cooler,” Campisi said. “The full understanding and mastering of the energetics of quantum systems and devices is urgently needed, and calls for a joint international effort in order to speed up technological development.” Explore further In quantum measurement cooling, the heat current is powered by energy provided via invasive measurements on an appropriate measurement basis fjψkig, without performing feed- back control. Solid arrows represent flow of energy. Credit: Campisi et al. Maxwell’s demon extracts work from quantum measurement More information: Lorenzo Buffoni et al. Quantum Measurement Cooling, Physical Review Letters (2019). DOI: 10.1103/PhysRevLett.122.070603 Researchers at the University of Florence and Istituto dei Sistemi Complessi, in Italy, have recently proved that the invasiveness of quantum measurements might not always be detrimental. In a study published in Physical Review Letters, they showed that this invasive quality can actually be exploited, using quantum measurements to fuel a cooling engine. © 2019 Science X Networklast_img read more

  • When markets down drink up

    first_imgTaking over the property that earlier housed V Spot, Charlie’s is one of those rare concept bars in town.Created with the omnipresent character of Charlie, from Charlie’s Angels in mind, Charlie’s is about keeping an eye on the stocks as you drink it up. The bar has screens all over that constantly update the prices of liquors as and how the market prices drop. The drops could be monumental or minimal, but it reflects on the prices on the screen and the guests can order a fresh round in those prices. Could it get any cooler? Also Read – ‘Playing Jojo was emotionally exhausting’Ok, we admit that keeping an eye on the screen constantly is a little distracting when you are out with friends – feel free to ask the staff! They have some incredibly friendly people working there. The main idea behind a bar like Charlie’s Bar Exchange is to provide the aspiring young Delhiite a place where he can come and try liquors he would have otherwise drank at home or in his car before he hit the parties, explains Nereen Tewari, one part of the brain behind Charlie’s. Also Read – Leslie doing new comedy special with NetflixSo for people who want to have their Jack Daniels at very easy prices, Charlie’s could just be the spot! But then it all depends on the market! Keep an eye out!They also have a great food spread and some insane cocktails. Do try the she Devil and the Bell Pepper Margarita for sure! The hot dogs have an excellent gourmet touch to it, full marks to the simple spaghetti they dished out – we loved it! Basic herbs and olive oil is a sure fire hit, always! The non-vegetarian and the vegetarian platters are great too – they offer an impressive array. Head over to Charlie’s for their great prices. The location is convenient and the ambience is excellently casual for a group of friends to put their feet up. Tewari also gave us a heads up on some great music nights they have planned for the spot so keep an eye on their Facebook page. A meal for two comes to Rs 1200 (without taxes and without alcohol) – but worry not! The food is quite worth the price and the liquor prices won’t pinch your pockets! Promise!last_img read more

  • No transport woes on April 13 assures govt

    first_imgKolkata: The top brass of the state Transport department held an immediate meeting on Wednesday with all transport operators, soon after a 6-hour bandh was called by Left Front on April 13 and assured that the transport services will remain unaffected. The meeting was held with representatives of all the transport operators and owners’ associations in Paribahan Bhavan at 8 pm on Wednesday. The operators assured that transport services will remain normal on April 13.The State Transport undertakings will deploy 3,700 buses and there will be special stress to ensure proper service from major transit points. There will be special monitoring for Howrah Station, Sealdah Station and Kolkata Airport. Moreover, there will be insurance coverage for vehicles in case of damage.last_img read more

  • 18 canines set to join Kolkata Police dog squad

    first_imgKolkata: The Kolkata Police has started off with its preparation to add 18 new dogs to its existing squad of 48.It may be recalled that a proposal was made in September 2011 when the added area came under the jurisdiction of the Kolkata Police to add 30 more dogs in two phases in the squad. The plan was to bring in 12 dogs into the service in the first phase and 18 in the second phase. According to a senior police officer, the 12 dogs were brought into service in mid 2017 and there training programme has completed recently. Also Read – Heavy rain hits traffic, flights”With completion of the training programme of the 12 dogs those were brought into service in the first phase, all necessary work to bring in the next 18 new dogs has started,” the officer said adding that committee comprising senior police officers and doctors will be formed to bring in the new members of the dog squad. The committee will take decision on crucial matters including the breed of dogs that will be procured. Based on the decision of the committee, a detailed proposal will be placed before the state government for further necessary sanctions. There are several issues like construction of kennel and recruitment of constables for the 18 new dogs that need to be carried out before the dogs are brought into the Dog Squad at the Police Training School (PTS) of the Kolkata Police. The officer said two constables need to be recruited for each dog. At present, there are total 48 dogs in the Dog Squad of the Kolkata Police and it includes the 12 newly added ones those are German Shepherd and Labrador. The dogs of different ages between 6 months to 10 months were procured from Hyderabad and sent to Gwalior for training by the Border Security Force (BSF). They dogs underwent the training for around six months and have been brought back to Kolkata. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killed”But we are yet to engage them in work as they need to get acclimatised to the weather condition here and it would take at least two months, then only they will be pressed for frisking operations as and when required,” the officer said. The dogs have been named as Dingo, Piki, Lara, Copper and Topper. Officers of the dog squad had prepared a list containing around 20 names and sent it to senior officers, who had finally chose 12 names out of it. This comes at a time when there will be a separate dog squad for the state secretariat, Nabanna.last_img read more

  • Reviving Sanskrit

    first_imgSanskrit, considered to be a difficult language, is losing its relevance today. But the language was brought centre stage by a New Delhi based organisation called NectarLand with the launch of Re-discovering Sanskrit, Volume 1 on February 14 at India Habitat Centre. The event was attended by over 65 participants from across the world with different walks of life. The book is an approach towards Sanskrit, loaded with artwork of international quality – with English to Sanskrit translation and transliteration accompanied with noteworthy facts and developments related to Sanskrit across the world.  Also Read – ‘Playing Jojo was emotionally exhausting’The book was launched by an esteemed panel of guests including Girish Jha, (Associate Professor, Special Centre of Sanskrit Studies, JNU), Lalit Das, (Ex-head, Industrial Design, IIT Delhi), Rajeshwari V Pandharipande, (Professor Emerita of Sanskrit, Linguistics, at the University of Illinois, Chicago, USA). We have tried to integrate ‘Design’ and ‘Sanskrit’ to make the learning process interesting so that the youth can connect with the language”, said Arya, Director, NectarLand. Also Read – Leslie doing new comedy special with Netflix“This initiative is a much awaited direction to introduce innovative and attractive language teaching tools for Sanskrit language. Popularising of Sanskrit calls for more initiatives to integrate technology like e-learning platforms, animations and digitisation of Sanskrit scriptures,” said Dr Girish Jha, Associate Professor, Special Centre of Sanskrit Studies, JNU. “Through beautiful illustrations, this book has really kept me engrossed. As Sanskrit is perceived to be a difficult language to learn, it becomes imperative to integrate such methods so as to keep the learners and tutors excited about it,” Das said.last_img read more

  • Death of Majid Ansari College students protest demanding arrest of accused

    first_imgKolkata: There was tension in Cooch Bihar following demonstrations led by students demanding arrest of those involved in the killing of Majid Ansari, a second year student.Ansari, who was injured after miscreants fired at him from a point blank range on July 13, died in a private nursing home in Siliguri on Wednesday night.Ansari (21) was a second year college student and had protested against the collection of money by some students assuring admission. He along with some of his friends had put up posters inside the college campus asking the freshers not to pay anything extra. Also Read – Rain batters Kolkata, cripples normal lifeWhen he was returning home on July 13, the miscreants came in two motor cycles and fired shots at him. They rode off leaving him on the road in a pool of blood. Majid was admitted to a private nursing home and the doctors was thinking of taking him to Delhi in an air ambulance. The students took out processions as soon as Majid’s mortal frame reached his house on Thursday afternoon.The students said the police did not arrest the main accused following pressure from some political bigwigs.Describing the incident as “most unfortunate”, Rabindranath Ghosh, state minister for North Bengal development said those involved in the incident will be arrested and no one will be spared.last_img read more