In football, there are constant power struggles, both on and off the field: players battling players, offenses battling defenses, the passing game battling the running game, coaches battling coaches, and new ways of thinking battling old ways of thinking. And then there are kickers. Battling no one but themselves and the goalposts, they come on the field in moments most mundane and most decisive. They take all the blame when they fail, and little of the credit when they succeed. Year in and year out, just a little bit at a time, they get better. And better. And better. Until the game is completely different, and no one even noticed that kickers were one of the main reasons why.If you’ve been reading my NFL column Skeptical Football this season, you may have noticed that I write a lot about kickers. This interest has been building for a few years as I’ve watched field goals drained from long range at an ever-increasing rate, culminating in 2013, when NFL kickers made more than 67 percent of the kicks they took from 50-plus yards, giving them a record 96 such makes. There has been a lot of speculation about how kickers suddenly became so good at the long kick, ranging from performance-enhancing drugs (there have been a few possible cases) to the kickers’ special “k-balls” to more kick-friendly stadiums.So prior to the 2014 season, I set out to try to see how recently this improvement had taken place, whether it had been gradual or sudden, and whether it was specific to very long kicks or reflected improvement in kicking accuracy as a whole.What I found fundamentally changed my understanding of the game of football.1And possibly offered insight into how competitive sports can conceal remarkable changes in human capability.The complete(ish) history of NFL kickingPro Football Reference has kicking data broken down by categories (0-19 yards, 20-29, 30-39, 40-59 and 50+ yards) back to 1961. With this we can see how field goal percentage has changed through the years for each range of distances:It doesn’t matter the distance; kicking has been on a steady upward climb. If we look back even further, we can see indicators that kicking has been on a similar trajectory for the entire history of the league.The oldest data that Pro Football Reference has available is from 1932, when the eight teams in the NFL made just six field goals (it’s unknown how many they attempted). That year, kickers missed 37 of 113 extra-point attempts, for a conversion rate of 67.3 percent. The following year, the league moved the goal posts up to the front of the end zone — which led to a whopping 36 made field goals, and a skyrocketing extra-point conversion rate of 79.3 percent. With the uprights at the front of the end zone, kickers missed only 30 of 145 extra points.For comparison, those 30 missed extra-point attempts (all with the goalposts at the front of the end zone) are more than the league’s 28 missed extra-point attempts (all coming from 10 yards further out) from 2011 to 2014 — on 4,939 attempts.In 1938-39, the first year we know the number of regular field goals attempted, NFL kickers made 93 of 235 field-goal tries (39.6 percent) to go with 347 of 422 extra points (82.2 percent). In the ’40s, teams made 40.0 percent of their field goal tries (we don’t know what distances they attempted) and 91.3 percent of their XPs. In the ’50s, those numbers rose to 48.2 percent of all field goals and 94.8 percent of XPs. The ’60s must have seemed like a golden era: Kickers made 56 percent of all field goals (breaking the 50 percent barrier for the first time) and 96.8 percent of their extra points.For comparison, since 2010, NFL kickers have made 61.9 percent of their field goal attempts — from more than 50 yards.In the 1960s, we start to get data on field goal attempts broken down by distance, allowing for the more complete picture above. In 1972, the NFL narrowed the hash marks from 18.5 yards from 40, which improved field goal percentages overall by reducing the number of attempts taken from awkward angles. And then in 1974, the league moved the goal posts to the back of the end zone — but as kick distances are recorded relative to the posts, the main effect of this move was a small (and temporary) decline in the extra-point conversion rate (which you can see in the top line of the chart above). Then we have data on the kicks’ exact distance, plus field and stadium type, after 1993.2This info is likely out there for older kicks as well, but it wasn’t in my data.So let’s combine everything we know: Extra-point attempts and distances prior to 1961, kicks by category from 1961 to 1993, the kicks’ exact distance after 1993, and the changing placement of goal posts and hash marks. Using this data, we can model the likely success of any kick.With those factors held constant, here’s a look at how good NFL kickers have been relative to their set of kicks in any given year3This is done using a binomial probit regression with all the variables, using “year taken” as a categorical variable (meaning it’s not treated like a number, so 1961, 1962 and 1963 may as well be “Joe,” “Bob” and “Nancy”). This is similar to how SRS determines how strong each team is relative to its competition.:When I showed this chart to a friend of mine who’s a philosophy Ph.D.,4Hi, Nate! he said: “It’s like the Hacker Gods got lazy and just set a constant Kicker Improvement parameter throughout the universe.” The great thing about this is that since the improvement in kicking has been almost perfectly linear, we can treat “year” as just another continuous variable, allowing us to generalize the model to any kick in any situation at any point in NFL history.Applying this year-based model to our kicking distance data, we can see just how predictable the improvement in kicking has actually been:The model may give teams too much credit in the early ’60s — an era for which we have a lot less data — but over the course of NFL history it does extremely well (it also predicts back to 1932, not shown). What’s amazing is that, while the model incorporates things like hashmark location and (more recently) field type, virtually all the work is handled by distance and year alone. Ultimately, it’s an extremely (virtually impossibly) accurate model considering how few variables it relies on.5So how accurate is this thing? To be honest, in all my years of building models, I’ve never seen anything like it. The model misses a typical year/distance group prediction by an average of just 2.5 percent. Note that a majority of those predictions involve only a couple hundred observations — at most. For comparison, the standard deviation for 250 observations of a 75 percent event is 2.7 percent. In other words, the model pretty much couldn’t have done any better even if it knew the exact probability of each kick!While there is possibly a smidge of overfitting (there usually is), the risk here is lower than usual, since the vast majority of each prediction is driven solely by year and distance. Here’s the regression output:I wish I could take credit for this, but it really just fell into place. Nerds, perk up: The z-value on “season” is 46.2! If every predictive relationship I looked for were that easy to find, life would be sweet.This isn’t just trivia, it has real-world implications, from tactical (how should you manage the clock knowing your opponent needs only moderate yardage to get into field goal range?) to organizational (maybe a good kicker is worth more than league minimum). And then there’s the big one.Fourth downIf you’re reading this site, there’s a good chance you scream at your television a lot when coaches sheepishly kick or punt instead of going for it on fourth down. This is particularly true in the “dead zone” between roughly the 25- and 40-yard lines, where punts accomplish little and field goals are supposedly too long to be good gambles.I’ve been a card-carrying member of Team Go-For-It since the ’90s. And we were right, back then. With ’90s-quality kickers, settling for field goals in the dead zone was practically criminal. As of 10 years ago — around when these should-we-go-for-it models rose to prominence — we were still right. But a lot has changed in 10 years. Field-goal kicking is now good enough that many previous calculations are outdated. Here’s a comparison between a field-goal kicking curve from 2004 vs. 2014:There’s no one universally agreed-upon system for when you should go for it on fourth down. But a very popular one is The New York Times’ 4th Down Bot, which is powered by models built by Brian Burke — founder of Advanced Football Analytics and a pioneer in the quantitative analysis of football. It calculates the expected value (either in points or win percentages) for every fourth-down play in the NFL, and tweets live results during games. Its 19,000-plus followers are treated to the bot’s particular emphasis on the many, many times coaches fail to go for it on fourth down when they should.A very helpful feature of the 4th Down Bot is that its game logs break down each fourth-down decision into its component parts. This means that we can see exactly what assumptions the bot is making about the success rate of each kick. Comparing those to my model, it looks to me like the bot’s kickers are approximately 2004-quality. (I asked Burke about this, and he agrees that the bot is probably at least a few years behind,6I don’t blame Burke or others for not updating their models based on the last few years. It’s good to be prudent and not assume that temporary shifts one way or the other will hold. Normally it is better to go with the weight of history rather than with recent trends. But in this case, the recent trends are backed by the weight of history. and says that its kicking assumptions are based on a fitted model of the most recent eight years of kicking data.7Here’s his full statement: “The bot is about 3-4 years behind the trends in FG accuracy, which have been improving at longer distances. It uses a kicking model fitted to the average of the recent 8-year period of data. AFA’s more advanced model for team clients is on the current ‘frontier’ of kick probabilities, and can be tuned for specific variables like kicker range, conditions, etc. Please keep in mind the bot is intended to be a good first-cut on the analysis and a demonstration of what is possible with real-time analytics. It’s not intended as the final analysis.”)But more importantly, these breakdowns allow us to essentially recalculate the bot’s recommendations given a different set of assumptions. And the improvement in kicking dramatically changes the calculus of whether to go for it on fourth down in the dead zone. The following table compares “Go or No” charts from the 4th Down Bot as it stands right now, versus how it would look with projected 2015 kickers8The exact values in the chart may differ slightly from the reports on the Times’ website because I had to reverse-engineer the bot’s decision-making process. But basically I’m assuming the model gets everything exactly right as far as expected value from various field locations, chances of converting a fourth-down attempt, etc., then recalculating the final expected value comparison using 2015 kickers.:Having better kickers makes a big difference, as you can see from the blue sea on the left versus the red sea on the right. (The 4th Down Bot’s complete “Go or No” table is on the Times’ website.)Getting these fourth-down calls wrong is potentially a big problem for the model. As a test case, I tried applying the 4th Down Bot’s model to a selection of the most relevant kicks from between 25 and 55 yards in 2013, then looked at what coaches actually did in those scenarios. I graded both against my kicking-adjusted results for 2013. While the updated version still concluded that coaches were too conservative (particularly on fourth-and-short), it found that coaches were (very slightly) making more correct decisions than the 4th Down Bot.The differences were small (coaches beat the bot by only a few points over the entire season), but even being just as successful as the bot would be a drastic result considering how absolutely terrible coaches’ go-for-it strategy has been for decades. In other words, maybe it’s not that NFL coaches were wrong, they were just ahead of their time!Time-traveling kickersHaving such an accurate model also allows us to see the overall impact kicking improvement has had on football. For example, we can calculate how kickers from different eras would have performed on a common set of attempts. In the following chart, we can see how many more or fewer points per game the typical team would have scored if kickers from a different era had taken its kicks (the red line is the actual points per game from field goals that year):The last time kickers were as big a part of the game as they are today, the league had to move the posts back! Since the rule change, the amount of scoring from field goals has increased by more than 2 points per game. A small part of the overall increase (the overall movement of the red line) is a result of taking more field goals, but most of it comes from the improvement in accuracy alone (the width of the “ribbon”).How does this compare to broader scoring trends? As a baseline for comparison, I’ve taken the average points scored in every NFL game since 1961, and then seen how much league scoring deviated from that at any given point in time (the “scoring anomaly”). Then I looked at how much of that anomaly was a result of kicking accuracy.9The scoring deviation on this chart is calculated relative to the average game over the period. The kicking accuracy is relative to the median kicker of the period.:Amid wild fluctuations in scoring, kicking has remained a steady, driving force.For all the talk of West Coast offenses, the invention of the pro formation, the wildcat, 5-wide sets, the rise of the pass-catching tight-end, Bill Walsh, the Greatest Show On Turf, and the general recognition that passing, passing and more passing is the best way to score in football, half the improvement in scoring in the past 50-plus years of NFL history has come solely from field-goal kickers kicking more accurately.10Side note, I’ve also looked at whether kicking improvement has been a result of kickers who are new to the league being better than older kickers, or of older kickers getting better themselves. The answer is both.The past half-century has seen an era of defensive innovation — running roughly from the mid-’60s to the mid-’70s — a chaotic scoring epoch with wild swings until the early ’90s, and then an era of offensive improvement. But the era of kickers is forever.Reuben Fischer-Baum contributed graphics.CORRECTION (Jan. 28, 2:22 p.m.): An earlier version of this article incorrectly gave the distances from which extra-point kicks were taken in 1933 and in recent years. Actual extra-point distances aren’t recorded.
OSU then-junior H-back Dontre Wilson (2) runs with the ball during a game against Indiana in Bloomington, Indiana. Credit: Samantha Hollingshead / Photo EditorFor three Ohio State football players, a new layer has been added to their offseason training programs.H-back Dontre Wilson, wide receiver James Clark and defensive tackle Robert Landers are going to be wearing scarlet and gray as multisport athletes, as the OSU track and field team announced on Tuesday that the trio would be joining the team for the 2016 season.“We’re excited to have our football players join the track and field program,” said OSU director of track and field Karen Dennis in a press release.All three of the athletes competed in track and field in high school, giving the team hope that they can immediately step up as contributors while balancing their spring football practices.“We realize the indoor season is short, and these men have a major responsibility to football. However, they are all talented athletes that may help us in the throwing and sprint events,” Dennis said in the release. “They have some work to do to get their ‘track legs’ back, but work is something they are very familiar with.”Wilson played in nine games in 2015 while dealing with a foot injury, managing seven catches for 63 yards. Considered one of the fastest players on the OSU football roster, Wilson ran track in his first three years at DeSoto High School in DeSoto, Texas. He is listed on the roster as a sprinter.Also listed as a sprinter is Clark, who was one of the faster short-distance runners in Florida while in high school in New Smyrna Beach.Clark placed in fifth place in the 100-meter dash and sixth in the 200-meter dash in the 2012 Florida Outdoor Championships, recording a personal-best 100-meter time of 10.43 seconds.He did not record any receptions last season, but was a contributor on special teams.While Wilson and Clark make their presences felt with their legs, the third Buckeye to join the track and field team, Landers, does his damage with his upper body.The 290-pound freshman did not see the field during his first year playing football in Columbus, but he brings a stellar track record to his new team.At Huber Heights High School, Landers was the Ohio Division I state champion in shot put in 2014 and finished fifth the following year. He also competed in hammer throw, discus and weight throw.“I appreciate coach Meyer and his staff working Landers, Wilson and Clark into our training schedule in an effort to strengthen our men’s program,” Dennis said.For the OSU track and field team, the season is already underway, as the Buckeyes already have three meets under their belts. They are set to continue their schedule in Birmingham, Alabama, on Friday in the Power 5 Conference Clash.
Ohio State senior forward Jae’Sean Tate finishes a dunk in the first half against Appalachian State on Dec. 16, 2017 at the Schottenstein Center. Credit: Ashley Nelson | Station ManagerThe last time a team from the Sun Belt Conference entered the Schottenstein Center two years ago, it handed Ohio State a crushing defeat that ended up being a major factor in keeping the Buckeyes out of the NCAA Tournament.Only four members of the team that lost to Texas-Arlington still put on a Scarlet and Gray jersey, but veterans Keita Bates-Diop and Jae’Sean Tate wouldn’t allow a night like that to occur a second time.Tate scored 19 points and Bates-Diop added 16 with eight rebounds to lead Ohio State (9-3) past Appalachian State (5-7), 80-67 Saturday evening. Freshman forward Kaleb Wesson had 16 points and eight rebounds and redshirt senior guard Kam Williams also was in double-figures, with 11 points.A week had passed since head coach Chris Holtmann’s team last played a game, which triggered thoughts of a possible letdown. The first half provided little excitement, with Ohio State unable to grasp control of the game until Bates-Diop created some momentum before the break.With less than two minutes remaining in the first half, Bates-Diop deflected an attempted pass from Mountaineers forward Hunter Seacat into the backcourt. Bates-Diop dove on the ball and passed it off to guard Andrew Dakich, who drove to the basket and left it for Tate for the two-handed slam.That play was part of a 6-0 run to close the half, and the Buckeyes led 40-27. Holtmann said that play sparked his team and picked the offense out of a drought.“That’s an expectation for an older guy to do that,” he said. “It’s an expectation for all our players to do that and I don’t think we did that every time tonight, which was disappointing. But that was a really, really special play.”Bates-Diop’s lay-in in the beginning of the second half gave Ohio State a 17-point lead. Then, following a fire alarm that caused people inside the arena to evacuate, the Mountaineers cut their deficit to nine with an 8-0 run.Leading 60-47 out of the under-12 media timeout, Wesson finished at the rim, Tate flew in for a dunk and Jackson banked in a 3 to give the Buckeyes a comfortable 20-point lead.Ohio State forced 18 turnovers. The Buckeyes shot 53 percent for the game.Entering the game, Appalachian State guards Ronshad Shabazz and Justin Forrest were averaging 21.8 and 16.8 points, respectively. Saturday against the Buckeyes, Shabazz had 15 and Forrest had 12, shooting a collective 1-for-8 from beyond the arc.“We knew we had to be active because they have a real high-powered motion offense,” Williams said. “So just getting deflections, taking it one stop at a time, one possession at a time. When we put that together, very few teams can execute against us.”Less than three minutes into the second half, prior to a Mountaineers free-throw attempt, the fire alarms sounded at the Schott and fans were told via an emergency response system inside the arena to exit the building. After roughly seven minutes, fans were allowed to re-enter the building and play resumed following a brief warm-up period.The event caused a delay of about 14 minutes.Sophomore center Micah Potter and freshman forward Kyle Young both returned from an ankle injury Saturday, after missing two games and one game, respectively. Potter played just one minute while Young played 13 minutes.Holtmann said Potter told him that his ankle was feeling “as good as it has felt” since suffering the injury on Nov. 19 against Northeastern. Holtmann added that Young played more than anticipated because of Wesson’s foul trouble.Up Next:The Buckeyes are back on the court Tuesday against The Citadel at 7 p.m.
The departing Fernando Torres will receive a special tribute by Atletico Madrid in their final game of the season against EibarThe forward’s contract will expire at the end of the season and he has now announced that he will leave his boyhood club for the second and final time.While Torres has not given any indication over his future plans, Atletico are determined to give their long-serving player a deserved fond farewell at the Estadio Wanda Metropolitano next month.“Fernando is a legend of our club,” said the club president Enrique Cerezo, according to Marca.Fati and Suarez shine against Valencia at Camp Nou Tomás Pavel Ibarra Meda – September 15, 2019 With a mesmerizing first half from Ansu Fati and a brace from Luis Suarez in the second half, Barcelona demolished Valencia at Camp Nou.Valencia…“We have always said that he will make the decision on his future because this is his home.“If he wants to continue his professional footballing career next season in another place we can only thank him for all he has given us, which is a lot, and tell him that the doors of Atletico Madrid will always be open to him when he decides to put an end to his career as a player.“Fernando Torres deserves the best of goodbyes as an Atletico Madrid player and that’s why I’m sure our fans will join us for a special day.“We are already working on making it an unforgettable day for the Atletico family and especially for Fernando.” Torres has said that he is already considering a number of offers as he ponders over his next step in football.
Jürgen Klopp managed to guide his team to the Champions League finals but he also has to take care of the domestic league as Liverpool are still fighting for the top four finish.The German coach admitted that it would be far better to play for the title but it hasn’t been possible this season as Manchester City have been phenomenal – but the top four finish would be a success as well.The former BVB manager spoke about his side’s season’s ending as he said, according to Telegraph:Report: Origi cause Klopp injury concerns George Patchias – September 14, 2019 Divock Origi injury in today’s game against Newcastle is a cause for concern for Jurgen Klopp.Perhaps with one eye on Tuesday’s trip to Italy…“It would be massive. It was actually the main target we had at the start of the season. You want to be champions but it was clear after a few months that would not be possible.”“The target is qualifying for the Champions League. That would be a big success. With the group we’ve got, with how we came to the final and playing with the biggest intensity in all parts, being ready again, then the injuries we had, it would be a massive success. It’s exactly what we want.”
After the chocking Spain elimination by Russia, on Sunday, Sergio Ramos is already looking at his side’s future, more specifically Qatar 2022.Spain was one of the favorites sides to win the 2018 World Cup, but with the unexpected defeat, last Sunday, against Russia, La Roja and Sergio Ramos, as he promised, have to wait four more years to pursue the title again.Zidane reveals Sergio Ramos injury concern for Real Madrid Andrew Smyth – September 14, 2019 Zinedine Zidane has put Sergio Ramos’ availability for Real Madrid’s trip to Sevilla next weekend in doubt after withdrawing him against Levante.This was the last World Cup for a lot of Spain’s key players, like Andrés Iniesta, Gerard Piqué and, probably, Pep Reina and David Silva. But that’s not the case for captain Sergio Ramos, who vowed he’ll be competing in the tournament in Qatar, in 2022, even though he’ll be 36 years old.“This team has a very good youth system, players with a lot of personality. I would like to keep going many more years. I am leaving this World Cup with a terrible pain. I feel obliged to reach Qatar with a white beard,” said the skipper, according to The New Arab.
Untitled-4The government is purchasing 40 gbps bandwidth from France to make up for temporary bandwidth scarcity but shortfall will still remain.The Bangladesh Submarine Cable Company Limited (BSCCL) is buying the bandwidth to address the gap between demand and supply, caused by the three-day interruption in the operation of the first submarine cable.During this shutdown, which began early Tuesday, the nation is set to experience a scarcity of 230 gpbs (giga byte per second) bandwidth.So, internet service providers say, internet speed will be slow although officials claim there will be no problem in connectivity.The second submarine cable (SEA-ME-WE-5) is contributing 110 gbps, but the country still has a scarcity of 80gpbs bandwidth, according official records.The month-long deal with France, done via US firm Cogent, costs the BSCCL $20,000 (Tk 1.6 million).”So ensuring uninterrupted internet will not be a problem,” said BSCCL managing director Mashiur Rahman.However, internet service providers say the speed of internet will be slower these three days. As a result, general users will suffer. IT organisations that depend on high-speed internet will suffer the most.”Internet is like oxygen nowadays. If the internet speed gets slowed down, it affects the whole day’s output. Most of the things we do, especially keeping in touch with the foreign clients, are reliant on online clouds,” said Shafiul Alam, chief executive officer of Blancer, an online marketplace.BSCCL data show, the country has a daily demand of 470 gbps bandwidth.The two submarine cables contribute to 270 gbps while the remaining 200 are imported from India through International terrestrial cable (ITC).*The article, originally published in Prothom Alo print edition, has been rewritten in English by Quamrul Hassan.
Members of Parliament react as the deputy speaker Lindsay Hoyle announces the results of the main vote on the EU Notification of Withdrawl Bill to the members of parliament in the House of Commons in central London. Photo: AFPBritish MPs overwhelmingly backed a bill on Wednesday empowering Prime Minister Theresa May to start negotiations on leaving the European Union, bringing Brexit a significant step closer.Members of the House of Commons voted by 494 votes to 122 for a law enabling May to trigger Article 50 of the EU’s Lisbon Treaty, which begins two years of talks on pulling out of the 28-nation bloc.“We’ve seen a historic vote tonight—a big majority for getting on with negotiating our exit from the EU and a strong, new partnership with its member states,” said Brexit minister David Davis.The unamended two-clause bill now moves to the House of Lords, where there may be more opposition from unelected peers—and where May’s Conservative party does not have a majority.But its passage through the Commons, where two-thirds of MPs had campaigned against Brexit ahead of the June referendum, puts May on course to begin the withdrawal process by the end of March, as she has vowed.Labour headachesThe referendum result sent shockwaves around Europe, spooking investors and raising fears for the future of the EU itself.In the early weeks, there was speculation that pro-European lawmakers might try to delay or even stop the Brexit process.May initially sought to bypass parliament, prompting an appeal to the Supreme Court that last month ruled she must obtain their approval to trigger Article 50.But during five days of debate on the resulting government bill, it became clear that most MPs would not stop the process—even if some warned that leaving Europe’s single market could be disastrous.The opposition Labour party and the smaller Scottish National Party (SNP) tabled amendments demanding guarantees on market access, workers’ rights and those of EU citizens in Britain.Each was defeated, although during the process the government was forced to promise lawmakers a vote on the final Brexit deal before it is concluded.Labour imposed a “three-line whip,” a tough disciplinary measure ordering its MPs not to oppose the legislation, ensuring it would pass.But some 52 Labour MPs rebelled in Wednesday’s vote, including business spokesman Clive Lewis who resigned shortly beforehand, bringing a fresh headache for embattled leftist leader Jeremy Corbyn.After two-thirds of Labour voters backed Brexit, many of them driven by concerns over mass immigration from the rest of the EU, Corbyn decided his party could not block the process.“Real fight starts now. Over next two years Labour will use every opportunity to ensure Brexit protects jobs, living standards & the economy,” Corbyn wrote on Twitter following the vote.But he was swiftly reprimanded in a reply by SNP leader Nicola Sturgeon: “How? You’ve just handed the Tories a blank cheque. You didn’t win a single concession but still voted for the bill. Pathetic.”‘Ode to Joy’SNP lawmakers voiced their frustration during Wednesday’s vote by singing Beethoven’s “Ode to Joy”, the EU’s anthem, before being told off by Deputy Speaker Lindsay Hoyle.But the outcome was celebrated by Brexiteers such as Nigel Farage, former leader of the UK Independence Party.“I never thought I’d see the day where the House of Commons overwhelmingly voted for Britain to Leave the European Union,” he wrote on Twitter.Liberal Democrat lawmaker Nick Clegg, the former deputy prime minister, said the vote would allow the government to pursue its aim of a hard Brexit, which will see Britain pull out of the single market.“There is no mandate for the hardest of hard Brexits the government favours, which risks leaving us poorer, weaker and more isolated,” he said.May has promised to prioritise controlling migration in the Brexit negotiations, even if that comes at the expense of giving up membership of Europe’s single market and its 500 million customers.
For physicists, measuring the precise magnitude of a physical quantity is a key to understanding quantum mechanics. However, there is a limit to how precise a measurement can be made, which is governed by quantum mechanical laws. Explore further A connection between quantum correlations and spacetime geometry 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. In search of a more precise measurement of quantum phases, researchers from the University of Science and Technology of China have demonstrated a new measurement method that relies on multi-photon entanglement and the interference effect it generates.“High resolution quantum phase measurements will help to measure other related physical parameters with high precision, such as time shift, distance, etc.,” physicist Fangwen Sun told PhysOrg.com. Sun is currently with the Optical Nanostructure Laboratory at Columbia University in New York.In their study, which is published in a recent issue of Europhysics Letters, Sun and his colleagues describe an experiment where they achieve a phase measurement precision that surpasses the standard quantum limit, and nearly reaches the Heisenberg limit. “The scheme can be generalized to high-photon-number states,” Sun said. “There is no fundamental obstacle to achieve the precision approaching the Heisenberg limit.”As the researchers explain, the standard quantum limit is not the ultimate limit for measurement precision of quantum phases. Using a technique called squeezed-state-based interferometry, previous studies have already surpassed the standard quantum limit. However, the Heisenberg limit is considered the ultimate limit. Although researchers have proposed a number of schemes to approach this limit, none have been realized due an effect called loss.“The standard quantum limit is achieved with a regular source of light such as a laser,” Sun explained. “It goes as 1/N1/2 for N photons. The Heisenberg limit goes as 1/N for N photons. It can be achieved with quantum sources of light that exhibit special entanglement properties.” But, he added, “It has been proven that the Heisenberg limit is the true quantum limit and cannot be surpassed.”In their experiment, the researchers designed a method that is not as sensitive to loss as the previous proposals, and so it has a higher probability of resulting in an extremely precise measurement. First, the physicists generated an entangled state by injecting a two-photon Fock state into a beam splitter. Then, the entangled photons traveled through a line of optical elements including a half-wave plate, interference filter, and phase shifter. At the end, the physicists used a recently developed method called quantum state projection to extract the phase information from the entangled photons. “It is the collective effect of all the photons that improves the precision,” Sun said, explaining why better photon entanglement results in higher precision measurements. “The higher entanglement, the more collective effect.”With their new measurement technique, the researchers achieved a phase measurement precision of 0.506 for a two-photon state and 0.291 for a four-photon state. By contrast, the precision values set by the standard quantum limit are 0.707 and 0.5, respectively. For comparison, the Heisenberg limit has values of 0.289 and 0.25, which are thought to be impossible to achieve.Nevertheless, the physicists hope that, with anticipated improvements in technology leading to more efficient multi-photon detectors, the measurements might yield even more precise results. More information: Sun, F. W.; Liu, B. H.; Gong, Y. X.; Huang, Y. F.; Ou, Z. Y., Guo, G. C. “Experimental demonstration of phase measurement precision beating standard quantum limit by projection measurement.” Europhysics Letters, 82 (2008) 24001. Copyright 2008 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: Measurement precision beats standard quantum limit (2008, April 21) retrieved 18 August 2019 from https://phys.org/news/2008-04-precision-standard-quantum-limit.html