Physicists Build a Quantum Gambling Machine

first_imgPhysicists have realized a quantum gambling machine using optical elements. From a helium-neon laser, a polarizer generates a single photon in a definite polarization state (horizontal or vertical). Then, Alice uses half wave plate 1 to transfer the definite state into a superposition state to alter the probability of the photon’s destination. The beam is split in the calcite beam splitter into beams A and B. Then Bob splits beam B with half wave plate 3 to influence the photon’s destination, and the second calcite beam splitter superposes beams B’ and A. Finally, three detectors labeled D1, D2, and D3 detect the photon in state B, B’, or A, respectively. Credit: Zhang, et al. Highest energy photons ever recorded coming from Crab Nebula 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. Citation: Physicists Build a Quantum Gambling Machine (2008, April 30) retrieved 18 August 2019 from But in quantum gambling, this kind of cheating is impossible, opening up the possibility for remote gambling. Researchers Yong-Sheng Zhang and colleagues from the University of Science and Technology of China have built such a quantum gambling machine using optical elements, which they describe in a recent issue of Europhysics Letters. “As far as I know, this is the first demonstration of a quantum gambling machine since L. Goldenberg et al. presented it in 1999,” Zhang told “It is a toy model of applications of quantum mechanics, and it may be used in real gambling.”First, the machine generates a photon, which has a definite polarization state of either vertical or horizontal. Then, to represent Alice the casino operator, a half wave plate transfers the photon into a superposition of horizontal and vertical states. In an equally distributed state, the photon would be half vertically polarized and half horizontally polarized. Then, a beam splitter splits the photon beam into beam A and beam B. At the end of the machine, there will be a 50-50 chance of the photon ending up in the player Bob’s “box” (his detector, B) or Alice’s detector, A. But the game offers other variables. To alter that 50-50 probability, for instance, Alice has the option of preparing a biased superposition state – for example, one that is more vertically polarized than horizontally polarized, or vice versa. Then, there would be a smaller chance that the photon would end up in Bob’s detector than in Alice’s detector. Quantum gambling machines may not be popping up at futuristic casinos any time soon, but the devices could have other uses – such as enabling physicists to study game theory in situations where cheating is impossible.center_img That’s because, in the quantum domain, opponents can always figure out what choice the other made when the game is over, thanks to superpositions of their actions. In the classical version of the “Pick the Winning Box” game, for example, a casino operator hides a ball in either box A or box B, and a player guesses the box that contains the ball in order to win. If the game were played remotely, the casino operator could easily lie about which box the ball was in if the player chose the winning box. Or, if the boxes were with the player, he could cheat by claiming that he found the ball when he did not. However, Bob has another option besides passively waiting to see if his detector gets the photon. Like Alice, Bob also has a half wave plate, and he can use it to split his beam B into two parts according to a splitting parameter of his choice. Then, one path of his split beam, B’, is superposed back with beam A. He would probably choose a higher splitting parameter if he thought that Alice had chosen a superposition state that was highly biased against putting the photon in his beam. In a sense, splitting his beam B gives Bob a second chance of winning, and – depending on the bet – winning a greater amount.If Bob’s detector doesn’t get the photon, then it will go to either Alice’s detector A or a third detector, B’. If Bob bet on the photon landing in detector A, and it does, then Bob wins a previously agreed sum, while a photon in detector B means Bob loses that sum (i.e. he chose the wrong box, in the classical analogy). Similarly, if he had bet on detector B, and the photon was detected there, he would win that bet, too. But he cannot bet on detector B’. So Bob and Alice both have sway over where the photon ends up. If Bob chooses a high splitting parameter and Alice had chosen a greatly biased superposition state (so that she increased the chance of having the photon in beam A), the photon would be more likely to go to detector A than B’, and Bob would win. But if Alice had chosen a more equal superposition state (so that beam B was just as likely to have the photon), the photon would be more likely to go to detector B’ than detector A, and Bob would lose. In this case, Bob would have been better off choosing a lower splitting parameter, or not splitting his beam at all. In a sense, Bob’s choice of his splitting parameter depends on how equally he thinks Alice prepared the original photon. The researchers figured out the optimal splitting parameter for Bob that would make him the most money for any superposition state that Alice chooses, for a game when Bob’s winnings would be 5 for detector A and 1 for detector B (and losing the same amount if his bet is wrong). They also found that Bob has a greater chance of losing than winning.As the researchers explain, this demonstration of a quantum gambling machine shows that quantum mechanics could have interesting implications in traditional game theory. For instance, quantum gambling might reveal insights into the foundations of game theory, survival games, and quantum communication. And quantum mechanics could also ensure fairness in remote gambling. “It is not clear how this gambling machine can affect people’s lives,” Zhang said. “However, with more and more things being used in gambling and trade [Super Tuesday: Markets Predict Outcome Better Than Polls, Scientific American, Feb. 2008], it can be conjectured that a quantum gambling machine whose security is guaranteed by the laws of physics may have some role in the future.”More information: Zhang, P.; Zhang, Y.-S.; Huang, Y.-F.; Peng, L.; Li, C.-F., and Guo, G.-C. “Optical realization of quantum gambling machine.” Europhysics Letters, 82, (2008) 30002.Copyright 2008 All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of This graph shows that Bob’s optimal splitting parameter has the value 0.27. This choice maximizes his gains over the possible choices that Alice could make for her superposition state (with the black square representing an equal superposition state and the light blue diamond representing a highly biased superposition state). Credit: Zhang, et al. Explore furtherlast_img read more

Dolphininspired sonar overcomes sizewavelength limitation

first_img More information: Yu Zhang, et al. “A biomimetic projector with high subwavelength directivity based on dolphin biosonar.” Applied Physics Letters. DOI: 10.1063/1.4896509 A highly focused or “directional” acoustic source offers the advantages of reducing noise interference, increasing the detection resolution, and enhancing sound intensity in the direction of interest. However, high directivity also requires an acoustic projector of large size in comparison with the wavelength, or high-frequency sound beams. Most sonar sources consist of large arrays, and the total size of the arrays is much larger than the wavelength. This problem is known as the size-wavelength limitation.While this problem plagues man-made sonar, Yangtze finless porpoises don’t seem to have the same limitation. Through millions of years of evolution and natural selection, the animal has developed a relatively small head (compared to man-made sonar) that can manipulate acoustic waves into a beam with high directivity. Porpoises and dolphins use these highly efficient biosonars for foraging, avoiding predators, and group coordination. Studies have shown that, despite serious vision degradation in water, dolphins can locate centimeter-sized objects 100 meters away using echolocation.Now a team of researchers from Xiamen University and the Institute of Hydrobiology of the Chinese Academy of Sciences in China, as well as The Pennsylvania State University in the USA, has designed and constructed a biomimetic sonar projector based on dolphin biosonar that achieves high directivity with a subwavelength sound source, overcoming the size-wavelength limitation. Their work is published in a recent issue of Applied Physics Letters.”The biomimetic projector breaks the size-wavelength limitation of traditional man-made sonar systems and provides a new concept for the realization of directional acoustic devices in the subwavelength regime,” coauthor Wenwu Cao, Professor at The Pennsylvania State University, told 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. (a) CT image of a neonate finless porpoise’s head. The region bounded by dashed lines represents the acoustic path. (b) Schematic diagram of the biomimetic projector. Credit: Zhang, et al. ©2014 AIP Publishing Citation: Dolphin-inspired sonar overcomes size-wavelength limitation (2014, October 8) retrieved 18 August 2019 from For bats and dolphins, hearing gene prestin adapted for echolocation Explore further The researchers’ work builds on their recent computed tomography (CT) studies of the complex structure of dolphin biosonar. The CT results show that the Yangtze finless porpoise has three main acoustic elements in its head: a skull, melon (fatty tissue), and air sacs. The researchers designed elements to mimic each of these features: a steel structure to mimic the skull, a gradient-index material to mimic the melon, and an air cavity to mimic the air sacs. “These three elements collectively could manipulate the omnidirectional wave generated from a subwavelength source into a highly directional one,” said Yu Zhang, project leader and Professor at the Key Laboratory of Underwater Acoustic Communication and Marine Information Technology of the Ministry of Education, Xiamen University.By successfully mimicking a dolphin’s acoustic elements, the researchers could achieve a very high-performing sonar system using a single sound source. Experiments and simulations showed that the bio-inspired sonar system could have both a miniature size and high directivity, breaking the size-wavelength limitation. Compared to the traditional strategy of using a horn for making directional beams with a bare subwavelength source (without all of the dolphin-inspired acoustic elements), the new biomimetic projector has superior angular resolution by an order of magnitude, in addition to other advantages. As it does not require complex circuitry, such a sonar system also has low energy consumption and very low cost.These properties make the bio-inspired sound projector promising for applications in underwater sonar, medical ultrasound, and other related areas. The researchers also want to investigate what happens when part of a dolphin’s biosonar is damaged.”In the future, we will focus more on the function of each component and the physical mechanism of beam focusing using gradient materials,” Cao said. “In principle, a dolphin’s acoustic structure should affect its biosonar function. But, we found a dolphin with partially damaged acoustic structure that lives independently and is able to avoid vessels, which suggests its echolocation ability is still intact. Our next goal is to find out why such acoustic structure damage did not cause catastrophe in the dolphin’s life. In addition, the biomimetic structure will be further optimized using artificial materials having an impedance gradient much larger than in the dolphin bisonar system. Hopefully we could apply the principle of the research finding to build better sonar systems in the near future.” “[Before now,] the compromise in size or frequency has inevitably brought many serious problems, including large physical size for low-frequency sound beams, high power consumption, and strong attenuation at high frequencies that reduces the detection distance,” he explained. “Therefore, it is important to be able to operate a directional sonar in the subwavelength range, which allows the sonar device to be made in small size with high resolution.” Journal information: Applied Physics Letters © 2014 The experimental set-up of the biomimetic projector, which breaks the size-wavelength limitation of traditional man-made sonar systems. Credit: Zhang, et al. ©2014 AIP Publishing ( —In a typical man-made sonar system, pulses of sound emitted by the projector bounce off hidden objects underwater. The echoes are then detected by the receiver to infer the location and size of the hidden objects.last_img read more

Celebrating masters and newbies

first_imgThe upcoming group art exhibition The Creativists, which starts from July 20 is about to enthrall the art lovers of the city as it will showcase a culmination of the works by veteran and contemporary artists. The aim is to showcase the quality works of masters as well as aspiring talent. The artistes participating in the event are Niren Sen Gupta, Kalicharan Gupta, Shobha Broota, Jagdish Chander, Jagadish dey, Sanjay Bhattacharya, Apte (sculpter) and Jiten Hazarika. Artist Shobha Broota’s work is soaked in a spiritual and meditative vision reverberating with rhythms in oscillating patterns.  Also Read – ‘Playing Jojo was emotionally exhausting’Her seemingly simple and minimal work invites the eye and blocks the perception to contemplate the form and its loosening unto the void. Hailed for its philosophical depth, the work commands concentration on one’s part to comprehend and appreciate it fully. Her creativity entails using various mediums including cloth, wool and iron mesh among others and the experimental quality of her work takes it beyond the plane of mere abstraction. She works on canvas, paper and board with equal energy to make balanced and tranquil compositions in variable textures and palette. Also Read – Leslie doing new comedy special with NetflixWhere Broota holds her share of spirituality in her art works, artist Sanjay Bhattachaya had openly admitted that he had been influenced by the works of Rembrandt and Dali. In his style, one can see light and shade techniques at play, trying to create a surrealistic imagery. Sanjay’s main themes are about city life in general in which inanimate objects figure more prominently. Sanjay Bhattacharya has painted in oil, watercolour and acrylic and has done sketches too.  Sanjay Bhattacharya, like most artists from Bengal is known more for watercolours and oil works. His initial paintings drew heavily on the style of Bikash Bhattacharya, but in later days Sanjay tried works in the style of other great artists of Bengal like Ganesh Pyne. In course of time Sanjay amalgamated various styles and developed on his own. With a display of urban life in a stylized manner, the works of Kalicharan Gupta’s imagery is complex and demands exploration.This exploration is both visual as well as architectural. There is of course color with subtle, tonal and compositional variations, moving towards making an impressive statement. Gupta’s works engage you both in contrast and harmony. Painted in a semi abstract style, his works invite you to view and weigh the impact of his unique style.WHEN : July 20- 25WHERE : Visual Art Gallery, India Habitat Centre Lodhi RoadTIMINGS : 11 am till 7 pmlast_img read more

SL to discuss Indias plan to establish bridge tunnel

first_imgSri Lanka’s new cabinet will soon discuss an Indian proposal to establish a sea bridge and an underwater tunnel to connect its Tamil Nadu state to the island nation.Cabinet spokesperson and Health Minister Rajitha Senaratne told Xinhua news agency on Tuesday that the Indian government had discussed the proposal with Prime Minister Ranil Wickremesinghe during his recent trip to New Delhi and the matter would be put for discussion to the Cabinet soon. Also Read – Nine hurt in accident at fireworks show in French resortIndia has proposed to construct a sea bridge and an underwater tunnel for both road and rail transport that would connect Rameswaram in Tamil Nadu with Sri Lanka through the Palk Strait.According to media reports, the Asian Development Bank (ADB) has shown interest to carry out the socio-economic feasibility study for this 23 km project. It is estimated to cost about $5 billion.Currently, the missing link of narrow corridor of about 23 km is serviced through makeshift ferry service.last_img read more

Believing in a bright tomorrow

first_imgThe heart of the national Capital is bearing witness to the saying: “To plant a garden is to believe in a tomorrow,” as the Indian International Centre (IIC) premises is all decked up for the season of festivals this year.Rajan Kumar Verma, the man who is responsible for the colourfull gardens at IIC has been working here for almost 30 years. This winter, IIC has been redecorated with several flowering plants and creepers in the premises to add on to the already available greenery. Starting from the entrance, the main lawn, the Rose garden to the Fountain lawn and Quadrangle lawn the place is home to flowering plants like Chrysanthemum, Marigold, Salvia, Petunia, Calendula, Tecoma, Aster, Antirrhinum (dog flower) and many more.  Also Read – Add new books to your shelfIIC has been known to the who’s who of Delhi for the quality cultural programmes and art exhibitions they host round the year, and also for the fig-honey ice cream they serve in the members-only cafeteria! But for nature lovers this is an area to bask in the sun and breathe in some fresh green air unavailable in the much polluted streets and populated localities. While you take a stroll in the open exhibition area, inquisitively observing the beautiful art works, you would also come across several hues of natural habitat attracting your attention swaying in the air rhythmically. When you sit at the cafe, looking out at the fountain you will see several Dahlias smiling up at you from the tubs placed by the water body. The artificial lake also has some water lilies floating on the surface. The creepers by the side of the boundary wall are host to many butterflies and bees as they visit the flowers to feed on honey and eventually become what we humans call ‘a marvellous photography subject’. In case you are waiting for a companion to arrive with whom you plan to visit the art exhibitions, or attend an informative seminar, do not simply sit with a long face thinking of getting late, rather  take a look around the peaceful area and pamper your senses with the well maintained greens of the trees, creepers and flowers.last_img read more

NKDA to introduce segregation of garbage at source from March 1

first_imgKolkata: In yet another big step towards a green and clean city, New Town Kolkata Development Authority (NKDA) will introduce segregation of garbage at source from March 1. This was decided at the board meeting of NKDA held recently.A programme to make the residents aware of the new mode of garbage collection will be held at Rabindra Tirtha on March 1. It will be introduced in phases, taking the residents into confidence. It will start from Action Area I in New Town and will be introduced in other areas in phases later. The garbage will be segregated at source. The residents will have to buy two bins, the specifications of which will be given by NKDA. There will be two bins earmarked for dry and wet waste. Also Read – Bose & Gandhi: More similar than apart, says Sugata BoseThe wet waste will be collected regularly and NKDA has proposed to start composting with wet waste. The body has already set up a plant and the compost is being used as manure for production of organic vegetables. The dry waste will be collected twice a week and NKDA is setting up a trenching ground at Patharghata. NKDA authorities have urged the residents to use the bins properly and put the waste in the specified bins. It may be mentioned that NKDA has taken several steps to make New Town a green and clean city. Waste water is being used to water roadside plants and state-of-the-art vehicles are being used to clean roads.last_img read more

Rang Matir Panchali to portray Kumartuli in a new avatar

first_imgKolkata: Kumartuli — the artisan hub of Kolkata — is all set to be transformed into a new avatar with a unique celebration of the artistry of the idol makers for the first time in the history of the city. A two- day carnival titled “Rang Matir Panchali”, will take place on Sunday and Monday to mark the occasion of World Art Day and Poila Baisakh on April 15.Three major lanes will be flanked by installations. Some of them will be in open air while others will be displayed inside several studios. An uneven patch of multiple colours will run from the gate along the ground, thus guiding the visitors along the exhibition trail. Also Read – Rs 13,000 crore investment to provide 2 lakh jobs: MamataExhibits will include idol-making, installations, paintings, sculptures, photographs, wall graffiti, street art etc. Modern art is blending with the traditional besides keeping Kumartuli’s rustic charm intact. About 30 artistes of Kumartuli are involved in this initiative including women idol makers China Pal and Mala Pal. Well-known theme makers Sushanta Pal and Partha Dasgupta are acting as mentors in the carnival. Three inmates from Pavlov Mental Hospital who have a fetish in art have also been roped in and they are working alongside Nabakumar Pal and Jiten Pal who are associated with the traditional idol making of Bagbazar Sarbojonin for years. Also Read – Lightning kills 8, injures 16 in state”It has been less than a month when we reached with the concept to the idol makers of Kumartuli. They welcomed the suggestion and formed an umbrella body named Kumartuli Art Forum, uniting the three unions for organising the event,” said Sabyasachi Chatterjee who runs a creative agency and is managing the event. A leading paint company that awards “Sharad Samman” to the best Durga Pujas across the city has extended a helping hand in the event. Pictures have been taken of various corners of the hub and of various activities of the idol makers. Their idle afternoons have also been captured through photographs. The two-day carnival will be inaugurated at Banamali Sarkar Street at 3 pm on Sunday.last_img read more

Kakolis road show garners stellar response in Barasat

first_imgKolkata: Kakoli Ghosh Dastidar, the outgoing Trinamool Congress MP from Barasat who is contesting the elections from the same seat for the third time, took out a massive road show in Barasat on Sunday morning in a bid to woo the voters.The road show, which was started from the Lokenath Temple on Barasat-Barrackpore Road, saw a huge surge of people as it went past various important places under her constituency. As the road show advanced, hundreds of Trinamool Congress supporters joined the rally, thereby contributing to the length of it. Also Read – Rs 13,000 crore investment to provide 2 lakh jobs: MamataMany youths and girls clad in colourful dresses were seen marching down the lanes and by-lanes of Barasat. A dance troupe also participated in the campaign. People congregated in large numbers on both sides of the road to catch a glimpse of Ghosh and the beautifully decorated tableaus that took part in the election rally. Ghosh was seen making her vote appeal to the people gathered on the road and also to those found standing on the balconies of their houses situated on the road. Ghosh waved her hands at the voters who readily reciprocated the gesture. Also Read – Lightning kills 8, injures 16 in stateGetting swayed by the response of the people, Ghosh later got down from the jeep and joined the dance group before the road show finally ended near Moyna area on Krishnanagar Road. In response to media questions, Ghosh said that Trinamool Congress candidates nominated by her party Supremo and Chief Minister Mamata Banerjee will win in all the 42 Lok Sabha seats in the state. “Mamata Banerjee is a great source of inspiration for me. She is doing very hard work while moving from place to place, setting examples for all of us. We should also toil hard taking lessons from her. Bengal has seen an unprecedented surge in development works ever since Banerjee became the Chief Minister,” Ghosh said. “All the 42 TMC candidates who are in the fray having the blessings of Mamata Banerjee, will come out victorious. We are getting tremendous response from the people who are extending their support to carry out the development works in the state,” Ghosh maintained. Reacting sharply to the comment of Special Observer Ajay V Nayak, she said: “It was a dark age for Bengal when the Left Front government used to rule the state. After becoming the Chief Minister, Banerjee restored the rule of law. Law and order situation is properly maintained here now and hence women can safely move from one place to another, even during late night.”last_img read more

Agencies from Delhi and Mumbai to examine health of state bridges

first_imgKolkata: State Public Works Department (PWD) minister Aroop Biswas during his budget speech in the Assembly said that various agencies from Delhi and Mumbai have been assigned to examine the health status of various bridges across the state that are owned by the department.While addressing the House, Biswas said that the agencies will carry out a detailed study on the bridges situated not only in the city but also in various districts. The agencies will submit a report to the government after six months after the examination is over. On the basis of the report submitted by the expert agencies, the PWD will take up the steps to repair or renovate those bridges which become weaker with the passing of time. Also Read – Rs 13,000 crore investment to provide 2 lakh jobs: MamataThe minister also criticized the erstwhile Left Front government for taking up maintenance issue properly. He also provided some data before the House to show how the Mamata Banerjee government increased the budgetary allocation for his department. “In the last eight years of the Left Front regime the budgetary allocation remained around Rs 6,113 crore in the PWD out of which around Rs 3,498 had been spent. During the last financial year, the budgetary allocation remained at Rs 16,801 crore but the expenditure outnumbered the allotment. The PWD had spent Rs 20,565 crore which shows that money was spent out of planned budget,” Biswas told the Assembly. Also Read – Lightning kills 8, injures 16 in stateIt may be mentioned that the PWD has created a bridge inspection and monitoring cell for ensuring proper health study of various bridges. The department has also taken up a project of constructing 20 capacity passenger shelters at important junctions of state highways in every district. One cell has been created headed by one Executive Engineer for proper monitoring of complaints and suggestions received on a whatsapp number 9073362000. The minister also mentioned that under ‘Baitarani’ scheme initiated by the state government the PED has taken up the construction of 402 more crematoriums and 20 electric furnaces are being constructed in various crematoriums.last_img read more