from the world's big
Researchers successfully sent a simulated elementary particle back in time
Don't start investing in flux capacitors just yet, though.
- The second law of thermodynamics states that order always moves to disorder, which we experience as an arrow of time.
- Scientists used a quantum computer to show that time travel is theoretically possible by reverting a simulated particle from an entropic to a more orderly state.
- While Einstein's general theory of relativity permits time travel, the means to achieve it remain improbable in nature.
In 1895 H.G. Wells published The Time Machine, a story about an inventor who builds a device that travels through a fourth, temporal dimension. Before Wells's novella, time travel existed in the realm of fantasy. It required a god, an enchanted sleep, or a bonk on the head to pull off. After Wells, time travel became popularized as a potentially scientific phenomenon.
Then Einstein's equations brought us into the quantum realm and there a more nuanced view of time. No less than mathematical logician Kurt Gödel worked out that Einstein's equations allowed for time travel into the past. The problem? None of the proposed methods of time travel were ever practical "on physical grounds."
So, "Why stick to physical grounds?" asked scientists from the Argonne National Laboratory, the Moscow Institute of Physics and Technology, and ETH Zurich before they successfully sent a simulated elementary particle back in time.
Fair warning: their results are tantalizing but will ultimately dishearten any time lords in training.
The great quantum escape
A quantum computer mixing chamber (Photo: IBM Research/Flickr)
Many of the laws of physics view the future and the past as a difference without a distinction. Not so with the second law of thermodynamics, which states that a closed system always moves from order to disorder (or entropy). Scramble an egg to make your omelet, for example, and you've added a whole lot of disorder into the closed system that was the initial egg.
This leads to an important consequence of the second law: the arrow of time. A process that generates entropy — such as your egg whisking — will be irreversible unless you input more energy. It's why an omelet won't reform back into an egg or why billiard balls don't spontaneously reform a triangle after the break. Like an arrow released, the entropy moves in a single direction, and we witness the effect as time.
We are trapped by the second law of thermodynamics, but the international team of scientists wanted to see if the second law could be violated in the quantum realm. Since such a test is impossible in nature, they used the next best thing: an IBM quantum computer.
Traditional computers, like the one you are reading this on, use a basic unit of information called a bit. Any bit can be represented as either a 1 or a 0. A quantum computer, however, uses a basic unit of information called a qubit. A qubit exists as both a 1 and a 0 simultaneously, allowing the system to compute and process information much faster.
In their experiment, the researchers substituted these qubits for subatomic particles and put them through a four-step process. First, they arranged the qubits in a known and ordered state and entangled them — meaning anything that happened to one affected the others. Then they launched an evolution program on the quantum computer, which used microwave radio pulses to break down that initial order into a more complex state.
Third step: a special algorithm modifies the quantum computer allow disorder to more to order. The qubits are again hit with a microwave pulse, but this time they rewind to their past, orderly selves. In other words, they are de-aged by about one millionth of a second.
According to study author Valerii M. Vinokur, of the Argonne National Laboratory, this is the equivalent of pushing against the ripples of a pond to return them to their source.
Since quantum mechanics is about probability (not certainty), success was no guarantee. However, in a two-qubit quantum computer, the algorithm managed a time jump an impressive 85 percent of the time. When it was upped to three qubits, the success rate dropped to about 50 percent, which the authors attributed to imperfections in current quantum computers.
The researchers published their results recently in Scientific Reports.
Bringing order from chaos
The results are fascinating and spur the imagination, but don't start investing in flux capacitors yet. This experiment also shows us that sending even a simulated particle back in time requires serious outside manipulation. To create such an external force to manipulate even one physical particle's quantum waves is well beyond our abilities.
"We demonstrate that time-reversing even ONE quantum particle is an unsurmountable task for nature alone," study author Vinokur wrote to the New York Times in an email [emphasis original]. "The system comprising two particles is even more irreversible, let alone the eggs — comprising billions of particles — we break to prepare an omelet."
A press release from the Department of Energy notes that for the "timeline required for [an external force] to spontaneously appear and properly manipulate the quantum waves" to appear in nature and unscramble an egg "would extend longer than that of the universe itself." In other words, this technology remains bound to quantum computation. Subatomic spas that literally turn back the clock aren't happening.
But the research isn't solely a high-tech thought experiment. While it will not help us develop real-world time machines, the algorithm does have the potential to improve cutting-edge quantum computation.
"Our algorithm could be updated and used to test programs written for quantum computers and eliminate noise and errors," study author Andrey Lebedev said in a release.
Is non-simulated time travel possible?
As Kurt Gödel proved, Einstein's equations don't forbid the concept of time travel, but they do set an improbably high hurdle to clear.
Writing for Big Think, Michio Kaku points out that these equations allow for all sorts of time travel shenanigans. Gödel found that if the universe rotated and someone traveled fast enough around it, they could arrive to a point before they left. Time travel could also be possible if you traveled around two colliding cosmic strings, traveled through a spinning black hole, or stretched space via negative matter.
While all of these are mathematically sound, Kaku points out that they can't be realized using known physical mechanisms. Similarly, the ability to nudge physical particles back in time remains beyond our reach. Time travel remains science fiction for all intents and purposes.
But time travel may one day become an everyday occurrence in our computers, making us all time lords (in a narrow sense).
- Time Travel is Possible. Einstein Taught Us That. - Big Think ›
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Andy Samberg and Cristin Milioti get stuck in an infinite wedding time loop.
- Two wedding guests discover they're trapped in an infinite time loop, waking up in Palm Springs over and over and over.
- As the reality of their situation sets in, Nyles and Sarah decide to enjoy the repetitive awakenings.
- The film is perfectly timed for a world sheltering at home during a pandemic.
Richard Feynman once asked a silly question. Two MIT students just answered it.
Here's a fun experiment to try. Go to your pantry and see if you have a box of spaghetti. If you do, take out a noodle. Grab both ends of it and bend it until it breaks in half. How many pieces did it break into? If you got two large pieces and at least one small piece you're not alone.
But science loves a good challenge<p>The mystery remained unsolved until 2005, when French scientists <a href="http://www.lmm.jussieu.fr/~audoly/" target="_blank">Basile Audoly</a> and <a href="http://www.lmm.jussieu.fr/~neukirch/" target="_blank">Sebastien Neukirch </a>won an <a href="https://www.improbable.com/ig/" target="_blank">Ig Nobel Prize</a>, an award given to scientists for real work which is of a less serious nature than the discoveries that win Nobel prizes, for finally determining why this happens. <a href="http://www.lmm.jussieu.fr/spaghetti/audoly_neukirch_fragmentation.pdf" target="_blank">Their paper describing the effect is wonderfully funny to read</a>, as it takes such a banal issue so seriously. </p><p>They demonstrated that when a rod is bent past a certain point, such as when spaghetti is snapped in half by bending it at the ends, a "snapback effect" is created. This causes energy to reverberate from the initial break to other parts of the rod, often leading to a second break elsewhere.</p><p>While this settled the issue of <em>why </em>spaghetti noodles break into three or more pieces, it didn't establish if they always had to break this way. The question of if the snapback could be regulated remained unsettled.</p>
Physicists, being themselves, immediately wanted to try and break pasta into two pieces using this info<p><a href="https://roheiss.wordpress.com/fun/" target="_blank">Ronald Heisser</a> and <a href="https://math.mit.edu/directory/profile.php?pid=1787" target="_blank">Vishal Patil</a>, two graduate students currently at Cornell and MIT respectively, read about Feynman's night of noodle snapping in class and were inspired to try and find what could be done to make sure the pasta always broke in two.</p><p><a href="http://news.mit.edu/2018/mit-mathematicians-solve-age-old-spaghetti-mystery-0813" target="_blank">By placing the noodles in a special machine</a> built for the task and recording the bending with a high-powered camera, the young scientists were able to observe in extreme detail exactly what each change in their snapping method did to the pasta. After breaking more than 500 noodles, they found the solution.</p>
The apparatus the MIT researchers built specifically for the task of snapping hundreds of spaghetti sticks.
(Courtesy of the researchers)
What possible application could this have?<p>The snapback effect is not limited to uncooked pasta noodles and can be applied to rods of all sorts. The discovery of how to cleanly break them in two could be applied to future engineering projects.</p><p>Likewise, knowing how things fragment and fail is always handy to know when you're trying to build things. Carbon Nanotubes, <a href="https://bigthink.com/ideafeed/carbon-nanotube-space-elevator" target="_self">super strong cylinders often hailed as the building material of the future</a>, are also rods which can be better understood thanks to this odd experiment.</p><p>Sometimes big discoveries can be inspired by silly questions. If it hadn't been for Richard Feynman bending noodles seventy years ago, we wouldn't know what we know now about how energy is dispersed through rods and how to control their fracturing. While not all silly questions will lead to such a significant discovery, they can all help us learn.</p>
What happens if we consider welfare programs as investments?
- A recently published study suggests that some welfare programs more than pay for themselves.
- It is one of the first major reviews of welfare programs to measure so many by a single metric.
- The findings will likely inform future welfare reform and encourage debate on how to grade success.
Welfare as an investment<p>The <a href="https://scholar.harvard.edu/files/hendren/files/welfare_vnber.pdf" target="_blank">study</a>, carried out by Nathaniel Hendren and Ben Sprung-Keyser of Harvard University, reviews 133 welfare programs through a single lens. The authors measured these programs' "Marginal Value of Public Funds" (MVPF), which is defined as the ratio of the recipients' willingness to pay for a program over its cost.</p><p>A program with an MVPF of one provides precisely as much in net benefits as it costs to deliver those benefits. For an illustration, imagine a program that hands someone a dollar. If getting that dollar doesn't alter their behavior, then the MVPF of that program is one. If it discourages them from working, then the program's cost goes up, as the program causes government tax revenues to fall in addition to costing money upfront. The MVPF goes below one in this case. <br> <br> Lastly, it is possible that getting the dollar causes the recipient to further their education and get a job that pays more taxes in the future, lowering the cost of the program in the long run and raising the MVPF. The value ratio can even hit infinity when a program fully "pays for itself."</p><p> While these are only a few examples, many others exist, and they do work to show you that a high MVPF means that a program "pays for itself," a value of one indicates a program "breaks even," and a value below one shows a program costs more money than the direct cost of the benefits would suggest.</p> After determining the programs' costs using existing literature and the willingness to pay through statistical analysis, 133 programs focusing on social insurance, education and job training, tax and cash transfers, and in-kind transfers were analyzed. The results show that some programs turn a "profit" for the government, mainly when they are focused on children:
This figure shows the MVPF for a variety of polices alongside the typical age of the beneficiaries. Clearly, programs targeted at children have a higher payoff.
Nathaniel Hendren and Ben Sprung-Keyser<p>Programs like child health services and K-12 education spending have infinite MVPF values. The authors argue this is because the programs allow children to live healthier, more productive lives and earn more money, which enables them to pay more taxes later. Programs like the preschool initiatives examined don't manage to do this as well and have a lower "profit" rate despite having decent MVPF ratios.</p><p>On the other hand, things like tuition deductions for older adults don't make back the money they cost. This is likely for several reasons, not the least of which is that there is less time for the benefactor to pay the government back in taxes. Disability insurance was likewise "unprofitable," as those collecting it have a reduced need to work and pay less back in taxes. </p>
What are the implications of all this?<div class="rm-shortcode" data-media_id="ceXv4XLv" data-player_id="FvQKszTI" data-rm-shortcode-id="3b407f5aa043eeb84f2b7ff82f97dc35"> <div id="botr_ceXv4XLv_FvQKszTI_div" class="jwplayer-media" data-jwplayer-video-src="https://content.jwplatform.com/players/ceXv4XLv-FvQKszTI.js"> <img src="https://cdn.jwplayer.com/thumbs/ceXv4XLv-1920.jpg" class="jwplayer-media-preview" /> </div> <script src="https://content.jwplatform.com/players/ceXv4XLv-FvQKszTI.js"></script> </div> <p>Firstly, it shows that direct investments in children in a variety of areas generate very high MVPFs. Likewise, the above chart shows that a large number of the programs considered pay for themselves, particularly ones that "invest in human capital" by promoting education, health, or similar things. While programs that focus on adults tend to have lower MVPF values, this isn't a hard and fast rule.</p><p>It also shows us that very many programs don't "pay for themselves" or even go below an MVPF of one. However, this study and its authors do not suggest that we abolish programs like disability payments just because they don't turn a profit.</p><p>Different motivations exist behind various programs, and just because something doesn't pay for itself isn't a definitive reason to abolish it. The returns on investment for a welfare program are diverse and often challenging to reckon in terms of money gained or lost. The point of this study was merely to provide a comprehensive review of a wide range of programs from a single perspective, one of dollars and cents. </p><p>The authors suggest that this study can be used as a starting point for further analysis of other programs not necessarily related to welfare. </p><p>It can be difficult to measure the success or failure of a government program with how many metrics you have to choose from and how many different stakeholders there are fighting for their metric to be used. This study provides us a comprehensive look through one possible lens at how some of our largest welfare programs are doing. </p><p>As America debates whether we should expand or contract our welfare state, the findings of this study offer an essential insight into how much we spend and how much we gain from these programs. </p>
Finding a balance between job satisfaction, money, and lifestyle is not easy.
- When most of your life is spent doing one thing, it matters if that thing is unfulfilling or if it makes you unhappy. According to research, most people are not thrilled with their jobs. However, there are ways to find purpose in your work and to reduce the negative impact that the daily grind has on your mental health.
- "The evidence is that about 70 percent of people are not engaged in what they do all day long, and about 18 percent of people are repulsed," London Business School professor Dan Cable says, calling the current state of work unhappiness an epidemic. In this video, he and other big thinkers consider what it means to find meaning in your work, discuss the parts of the brain that fuel creativity, and share strategies for reassessing your relationship to your job.
- Author James Citrin offers a career triangle model that sees work as a balance of three forces: job satisfaction, money, and lifestyle. While it is possible to have all three, Citrin says that they are not always possible at the same time, especially not early on in your career.