Scientists make holograms of atoms using electrons

first_img The scientists, Ymkje Huismans from the FOM-Institute AMOLF in Amsterdam, The Netherlands, and an international research team have published their study in a recent issue of Science Express.“What we have experimentally demonstrated is that it is possible to make holograms by taking an electron out of a molecule and, using a laser field, redirect the electron toward the molecule,” coauthor Marc Vrakking, of the FOM-Institute AMOLF and the Max Born Institute in Berlin, told PhysOrg.com.In their experiments, the scientists beamed an intense infrared laser light at an atom or molecule, which resulted in the atom or molecule becoming ionized and releasing an electron. The laser field causes the liberated electron to oscillate away from and toward the ion. Sometimes, an electron and ion collide, releasing a very short burst of radiation. Because the electron motion is fully coherent, meaning it always has the same phase, the scientists realized that they could apply holographic techniques to record information about the ion and electron. The key to holographic electron imaging is to observe the interference between a reference wave (which is emitted by the electron and doesn’t interact with the ion) and a signal wave (which scatters off the ion and encodes its structure). When the reference wave and signal wave interfere on a detector, the encoded information about the electron and ion is stored and can be viewed in the future. As the scientists explained, the result is a hologram of an atom produced by its own electrons.The researchers also developed theoretical models to simulate their measurements, confirming that the hologram had stored spatial and temporal information about the electrons and ions. By using the holographic structures to develop a new kind of ultra-fast photoelectron spectroscopy, researchers could be able to directly measure electron and ion movements on the attosecond timescale. This ability would be useful for understanding chemical reactions at the most basic level, particularly in molecules that cannot be easily studied by other methods. Scientists track electrons in molecules (PhysOrg.com) — While holography is often associated with artistic 3D images, it can also be used for many other purposes. In a new study, scientists have created holograms of atoms using laser-driven electron motion, which could lead to a new type of ultra-fast photoelectron spectroscopy. In the future, this type of holography could enable scientists to study the structures of molecules in a more direct way than before. This velocity map image shows the velocity distribution of ionized electrons, which are used to create a hologram of a Xenon atom. Image credit: Y. Huismans, et al. ©2010 Science. 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. Copyright 2010 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Citation: Scientists make holograms of atoms using electrons (2011, January 6) retrieved 18 August 2019 from https://phys.org/news/2011-01-scientists-holograms-atoms-electrons.html Explore further More information: Y. Huismans, et al. “Time-Resolved Holography with Photoelectrons.” Science Express. 16 December 2010. DOI:10.1126/science.1198450last_img read more

Researchers create onchip interference between pairs of photon sources

first_imgSchematic of device operation. Credit: Nature Photonics (2013) doi:10.1038/nphoton.2013.339 © 2014 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. Explore further Journal information: Nature Photonics More information: On-chip quantum interference between silicon photon-pair sources, Nature Photonics (2013) DOI: 10.1038/nphoton.2013.339AbstractLarge-scale integrated quantum photonic technologies will require on-chip integration of identical photon sources with reconfigurable waveguide circuits. Relatively complex quantum circuits have been demonstrated already, but few studies acknowledge the pressing need to integrate photon sources and waveguide circuits together on-chip8, 9. A key step towards such large-scale quantum technologies is the integration of just two individual photon sources within a waveguide circuit, and the demonstration of high-visibility quantum interference between them. Here, we report a silicon-on-insulator device that combines two four-wave mixing sources in an interferometer with a reconfigurable phase shifter. We configured the device to create and manipulate two-colour (non-degenerate) or same-colour (degenerate) path-entangled or path-unentangled photon pairs. We observed up to 100.0 ± 0.4% visibility quantum interference on-chip, and up to 95 ± 4% off-chip. Our device removes the need for external photon sources, provides a path to increasing the complexity of quantum photonic circuits and is a first step towards fully integrated quantum technologies.center_img In the quest to create a truly useful quantum computer, researchers focus on single areas of research that in the end can hopefully be taken together to reach the ultimate goal. In this new effort, the researchers sought a way to allow for observation of quantum interference on a single chip, and report that they have succeeded by creating what some have described as the most complex quantum circuit ever made.To allow for observing quantum interference, scientists have discovered, two virtually identical photons are needed, which means they need to be produced from two identical photon sources—no easy feat, but not impossible as the researchers have proven.The researchers built a chip that is able to accept a laser beam pumped directly into it—that beam is used as the basis for forming photon pairs by means of interaction with a piece of silicon. The quantum light produced was then combined using a beam splitter (which was also integrated into the chip). The path length of the photon beams was controlled by modifying the temperature of the waveguides which allowed for observing two-photon quantum interference. The team reports observations of “up to 100 ± 0.4% visibility quantum interference on-chip up and up to 95 ± 4% off-chip.”The team suggests their apparatus (basically, a quantum system on a chip) makes unnecessary the need for external photon sources creating a path towards a true quantum computer. They also note that what they’ve created has been achieved without resorting to reinventing fabrication methods—their system can use methods very similar, they say, to those for other CMOS devices, making bulk production relatively easy. They also suggest their device could very well pave the way to multiple photon pair sources which if developed to work together could allow for the construction of highly efficient devices.The team next plans to scale up their chip to allow for adding quantum processing tasks. (Phys.org) —A team made up of researchers from several countries has succeeded in creating a chip that allows for observation of the interference between silicon photon-pair sources. In their paper published in Nature Photonics, the team describes the nature of their chip, how it works and ways it might be used. Citation: Researchers create on-chip interference between pairs of photon sources (2014, January 15) retrieved 18 August 2019 from https://phys.org/news/2014-01-on-chip-pairs-photon-sources.html On-chip quantum buffer realizedlast_img read more

Bumblebees found to do better in urban settings than in agricultural areas

first_imgCredit: CC0 Public Domain Journal information: Proceedings of the Royal Society B Bumblebees are generally considered to be one of the friendlier bees that people encounter. Despite their large, round size, they tend to elicit less fear due to their non-threatening behavior. And according to a study done by the team in Britain, they also appear to find more success in urban areas than they do in agricultural areas. They came to this conclusion by conducting an extensive field study.The study consisted of capturing queen bees in a local park and putting them into nest boxes where they laid eggs. The nest boxes were then placed at 38 sites between Basingstoke and London and monitored for approximately 10 weeks—the average lifespan of a bumblebee colony. Each colony received a visit once a week—at night when all members would be present. During each visit, the researchers counted all members of the colony and noted how much nectar and pollen had been stored. They also removed cuckoo bumblebees (other bee species that lay their eggs in bumblebee colonies) and gynes (males capable of reproducing).The researchers found that that bumblebee colonies in cities produced far more males and gynes than did those in agricultural areas. They also found that both city and village colonies had much higher populations than the agricultural colonies. Those colonies located in agricultural areas also tended to have more cuckoo bumblebee invasions.The researchers were not able to say for sure why the bumblebees appeared to do better in urban and village settings, but suggest it could be due to a variety of factors. Agricultural areas tend to have crops that only bloom for a short time, they note, and which are exposed to pesticides and other toxic chemicals. Cities and villages, on the other hand, have a wide variety of flowers that bloom at different times. Citation: Bumblebees found to do better in urban settings than in agricultural areas (2018, June 27) retrieved 18 August 2019 from https://phys.org/news/2018-06-bumblebees-urban-agricultural-areas.html Explore further A team of researchers with the University of London and Imperial College London has found through field experiments that bumblebee colonies tend to do better in urban environments than agricultural environments. In their paper published in Proceedings of the Royal Society B, the group describes their study and what they found.center_img Environmental threats put bumblebee queens under pressure More information: Ash E. Samuelson et al. Lower bumblebee colony reproductive success in agricultural compared with urban environments, Proceedings of the Royal Society B: Biological Sciences (2018). DOI: 10.1098/rspb.2018.0807AbstractUrbanization represents a rapidly growing driver of land-use change. While it is clear that urbanization impacts species abundance and diversity, direct effects of urban land use on animal reproductive success are rarely documented. Here, we show that urban land use is linked to long-term colony reproductive output in a key pollinator. We reared colonies from wild-caught bumblebee (Bombus terrestris) queens, placed them at sites characterized by varying degrees of urbanization from inner city to rural farmland and monitored the production of sexual offspring across the entire colony cycle. Our land-use cluster analysis identified three site categories, and this categorization was a strong predictor of colony performance. Crucially, colonies in the two clusters characterized by urban development produced more sexual offspring than those in the cluster dominated by agricultural land. These colonies also reached higher peak size, had more food stores, encountered fewer parasite invasions and survived for longer. Our results show a link between urbanization and bumblebee colony reproductive success, supporting the theory that urban areas provide a refuge for pollinator populations in an otherwise barren agricultural landscape. © 2018 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

The varied colours of life

first_imgAll art enthusiasts can find their way to IHC as Bhiku Ram Jain Foundation in association with Art Mall brings to us the group art show Colour Of Life – 14. The show is a part of their annual All India Art Exhibitions. The exhibition will display the art works of about 70 eminent and upcoming artistes in the discipline of paintings, sculptures, graphics, drawings, photography and digital art from across the country. The works on display celebrate the theme of colourful aspect through an individualistic makeover by the artistes, bringing the hopes, aspirations, achievements and challenges before the participating artistes. The overall effect on the canvas shows graphic detailing and symbolic forms to highlight such ideas. Also Read – ‘Playing Jojo was emotionally exhausting’A set of four unique sandal wood sculptures will be displayed made way back in 20th century by Mali Chand Jangid from Churu, Rajasthan. Eminent artistes like Jatin Das, Niren Sen Gupta, Vijender Sharma, Om Prakash said that the selection of the participants is done by an organising committee where emphasis of selection is based on creating an aura for enhance of colours empowerment which forms as a mission to bring together the largely untouched segments of genuinely art works before a gamut of art lovers who have shielded away from the gallery doors, intimidated by price tags and name droppings thus making it an art-friendly show for artistes and the art lovers alike. Also Read – Leslie doing new comedy special with NetflixThe show will be inaugrated by Prof Rajeev Lochan , Director National Gallery of Modern Art, Prof S N Lahiri, Principal Delhi College of Art, K K Chakravarty, Chairman Lalit Kala Academy , Jatin Das along with Her Excellency Milena Santana-Ramirez, Ambassador Extraordinary and Plenipotentiary of the Bolivarian, Republic of Venezuela along with Andrea Kucerova, Deputy Head of Mission, Political Affairs, Embassy of the Czech Republic.When:1 – 3 JuneWhere: Visual Art Gallery, India Habitat CentreTimings: 11am – 7pmlast_img read more

HMC ensures errorfree data collection to check vectorborne diseases

first_imgKolkata: Howrah Municipal Corporation (HMC) has taken a major step to ensure error free collection of data for a survey report that needs to be prepared to check vector-borne diseases.For the first time, the top brass of the civic body, starting from Mayor to ward councillors, will visit different areas to supervise the data collection process of the health workers.There are around 2,500 health workers under the HMC. They visit door to door to collect data and based on the same, a report is prepared. It is the survey report on which the senior officials of the civic body rely while chalking out a plan of action to check vector-borne diseases. As per the plan of action, all tasks are carried out to ensure the same. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedThe need of supervising the data collection process was realised during a meeting held on Monday and the work in this regard has started in full swing from Tuesday onwards.When contacted, Bhaskar Bhattacharjee, Member Mayor-in-Council (Health), said: “The step has been taken to ensure that the health workers collect the data properly as there are various technical aspects into the collection of data.”On Thursday, Bhattacharjee himself visited ward number 63 to verify the data that is being collected by the health workers and councilors are also assisting the health workers in carrying out the survey. Also Read – Naihati: 10 councillors return to TMC from BJPIt is helping the health workers to be more informed about the process of data collection.Once the data collection is done, it will be compiled into a single report by the concerned officers of the civic body’s health department and there will be a detailed discussion on the report to prepare the plan of action to take vector control measures. It may be mentioned that the HMC has already formed a high power monitoring committee for better execution of work to check-vector borne diseases and the committee is headed by Mayor Dr Rathin Chakraborty.Bijin Krishna, commissioner, is the convenor, and Bhattacharjee and other senior officials are members of the committee. The committee members will hold a meeting every week to take proactive steps so that people do not face any problem due to vector-borne diseases in any of the 66 wards of the civic body.last_img read more

17yrold kills self while on video call with girlfriend

first_imgKolkata: In a sensational incident, a 17-year-old youth streamed his suicide live on a social networking app while doing a video chat with his girl friend.The victim identified as Suraj Roy (17), was a student of class XII. He hanged himself from the ceiling of his house and showed the way he committed suicide to his girl friend. The victim was a student of Padmapukur High School in Baruipur.The incident took place in the Salepur village area under Baruipur police station. The incident triggered tension in the area. Police on Thursday morning recovered the body from the house and sent the body for the post-mortem. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedThe incident occurred on Wednesday night when the victim engaged in a heated altercation with his girl friend through a video call on a social networking app. The family members of the victim, however, lodged a complaint against his girl friend at the local police station. They brought the charges of abatement to suicide against the girl with whom the victim had a relationship for the past few months.The victim’s mother told the police that he called up his girlfriend after having his dinner at around 11 pm on Wednesday. During the phone call, he was found to be shouting. It appeared that they were involved in a verbal duel. Also Read – Naihati: 10 councillors return to TMC from BJPFollowing the incident, the victim might have made a video call to his girl friend and streamed his suicide live. The girl told the matter to her elder sister, who in turn reported the this to the friends of the victim.His friends rushed to his house and informed his mother. As he did not open the door despite repeated knocks, locals broke open the door only to find him hanging. After being informed, police reached the spot and recovered the body. The body was sent for an autopsy. No suicide note was found inside the room. Police have started a detailed probe into the incident. According to a preliminary investigation, police suspect that he had committed suicide due to depression. The exact cause is yet to be confirmed. The mobile phone of the victim is being examined by the police officers.It may be mentioned that in a similar incident, a class XII girl from Sonarpur area in the same district, went live on a social networking site in the similar fashion and committed suicide by hanging from the ceiling fan in June this year.A 40-year-old man also committed suicide in the similar manner in Siliguri earlier this month.last_img read more

BJP worker held on charges of abetment to suicide

first_imgBALURGHAT: South Dinajpur’s district BJP president, Subhendu Sarkar, was arrested on Monday night from Balurghat’s Raghunathpur on charges of abetting a female party worker to commit suicide.Police said the late female Saffron party worker Moushumi Mazumder (45), who was a resident of Sherpur under Banshihari police station area, committed suicide by hanging self at her residence on June 5.Her husband, Pradip Mazumder, lodged an official complaint at Banshihari police station on June 6 against Sarkar including four others, alleging his wife was forced to commit suicide following Sarkar and his party member’s mental torture, harassment and insult. Also Read – Rain batters Kolkata, cripples normal lifeAfter receiving the complaint, police initiated a probe against him and his men. An arrest warrant had also been issued.Police on Tuesday produced Sarkar at Gangarampur sub-divisional court pleading for seven-day police remand. The judge, however, granted three-day police remand. He had been kept under tight security arrangements. A medical test was also conducted.According to a BJP party source, Mazumder was an active party worker. She had also contested civic poll in Buniadpur with the party ticket a few months before. Later, she had developed misunderstandings with Sarkar. Besides, she attacked Sarkar while attending a party meeting on November 30 at Buniadpur, where she had slapped Sarkar in front of party workers and leaders. Following her misconduct, she was ousted from party by Sarkar.Sarkar, however, rubbished the charges being brought against him. “Neither he nor his party men was responsible for her suicide,” Sarkar said.last_img read more

Ramapada Chowdhury breathes his last at 95

first_imgKolkata: Acclaimed Bengali writer Ramapada Chowdhury, whose story Abhimanyu was made into a Hindi movie Ek doctor ki maut, died at a city hospital on Sunday, his family said. He was 95 and has left behind his wife and two daughters.He was admitted to the hospital on July 21 with old age ailments including lung problem. He died of cardiac arrest at 6:30 pm, a spokesman of the hospital said.Abhimanyu was based on the life and work of Dr. Subhas Mukhopadhyay who created India’s first and the world’s second test-tube baby in 1978. Director Tapan Sinha turned the story into a award winning Hindi film Ek doctor ki maut in 1990. Mrinal Sen’s Hindi film Ek din achanak (1989) was also based on Chowdhury’s story Beej. Also Read – Rain batters Kolkata, cripples normal lifeChowdhury had penned famous literary works such as Pratham Prahar (1954), Banpalashir padabali (1960), Ekhoni (1969), Kharij, Bari badle jay (1988), Abhimanyu (1982). He was conferred the Sahitya Academy award for Bari badle jay in 1988.Born on December 28, 1922 at Kharagpur, Chowdhury’s most active years were between 1950s and ’80s. His last book, Harano Khata was published in 2015.Many of his works had also been made into critically acclaimed Bengali films. He was also the recipient ofRabindra Puraskar, Ananda Puraskar and Rabindranath Tagore Memorial International Prize.last_img read more

Private publishing houses to be under govt scanner post Milkha Singh goofup

first_imgKolkata: The state government will now keep an eye on the private book publishing houses and will take action, particularly in case of misinformation or wrong portrayal of famous personalities in books.The decision was taken in a meeting with a number of publishers in the city, that was chaired by state Education minister Partha Chatterjee. The meeting was held in the wake of actor Farhan Akhtar pointing out a blooper in a Bengali book that had depicted him as legendary athlete Milkha Singh. The actor had tweeted on Sunday, urging state Education minister Partha Chatterjee to request the publisher to recall and replace the book.It may be mentioned that the state Education department has already identified the publisher as Anomy Publication, situated at 57/1A, College Street. The owner of the publishing house has claimed that it was a big mistake on their part and said that they have already started withdrawing the copies of the books that have been circulated.last_img read more

Genderbased colours in toys can spur harmful stereotypes

first_imgToymakers should avoid gender- labelling toys, and create items for both boys and girls in a wide range of colours, say scientists who found that children’s perception of what is appropriate for a gender can be easily manipulated. The study is also the first to show that a boy’s liking of blue and a girl’s preference for pink is not just a Western construct, but is also a phenomenon in urban Asian societies.The researchers from University of Hong Kong recruited 129 Chinese children aged between five and seven from two kindergartens in Hong Kong. Also Read – Add new books to your shelfFirst they assessed the children’s preference for pink versus blue by showing them cards and toys in these colours.Then the children were presented with yellow and green cards and toys.They were randomly divided into so-called label and no-label groups.Children in the no-label group were presented with coloured cards and toys which had no reference to a specific gender and these children consequently expressed no preference for a specific colour.However, preschoolers in the label group were told that yellow was a girl’s colour and green a boys’ colour, and corresponding gender differences emerged in the choices they made. Also Read – Over 2 hours screen time daily will make your kids impulsive Apart from randomly assigning children to these two groups, the children’s pre-existing preferences for yellow and green were statistically controlled, so the resulting difference between the groups speaks strongly to a causal effect of the gender labels.According to the researchers, the gender differences between preferred colours in children is noteworthy because it is so much more prominent than most other psychological differences between the sexes. “Our findings support the notion that gender-typed liking for pink versus blue is a particularly salient gender difference,” said Sui Ping Yeung from University of Hong Kong.”Moreover, our findings reveal that gender differences could be created merely by applying gender labels,” Yeung said.The findings, published in the journal Sex Role support previous research that highlighted the strong influence that gender labels such as “for boys” or “for girls” might have. Further, the observations are in line with gender schema theory that says that once children have learnt a specific gender identity, their behaviour will be guided by the standards set as being appropriate for their specific sex.These will guide them later in life on how they interact and adapt to their surroundings, for instance, when taking on chores around the house, such as cooking, cleaning or repairing things.last_img read more