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).

3D printing might save your life one day. It's transforming medicine and health care.

What can 3D printing do for medicine? The "sky is the limit," says Northwell Health researcher Dr. Todd Goldstein.

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Maps show how CNN lost America to Fox News

Is this proof of a dramatic shift?

Strange Maps
  • Map details dramatic shift from CNN to Fox News over 10-year period
  • Does it show the triumph of "fake news" — or, rather, its defeat?
  • A closer look at the map's legend allows for more complex analyses

Dramatic and misleading

Image: Reddit / SICResearch

The situation today: CNN pushed back to the edges of the country.

Over the course of no more than a decade, America has radically switched favorites when it comes to cable news networks. As this sequence of maps showing TMAs (Television Market Areas) suggests, CNN is out, Fox News is in.

The maps are certainly dramatic, but also a bit misleading. They nevertheless provide some insight into the state of journalism and the public's attitudes toward the press in the US.

Let's zoom in:

  • It's 2008, on the eve of the Obama Era. CNN (blue) dominates the cable news landscape across America. Fox News (red) is an upstart (°1996) with a few regional bastions in the South.
  • By 2010, Fox News has broken out of its southern heartland, colonizing markets in the Midwest and the Northwest — and even northern Maine and southern Alaska.
  • Two years later, Fox News has lost those two outliers, but has filled up in the middle: it now boasts two large, contiguous blocks in the southeast and northwest, almost touching.
  • In 2014, Fox News seems past its prime. The northwestern block has shrunk, the southeastern one has fragmented.
  • Energised by Trump's 2016 presidential campaign, Fox News is back with a vengeance. Not only have Maine and Alaska gone from entirely blue to entirely red, so has most of the rest of the U.S. Fox News has plugged the Nebraska Gap: it's no longer possible to walk from coast to coast across CNN territory.
  • By 2018, the fortunes from a decade earlier have almost reversed. Fox News rules the roost. CNN clings on to the Pacific Coast, New Mexico, Minnesota and parts of the Northeast — plus a smattering of metropolitan areas in the South and Midwest.

"Frightening map"

Image source: Reddit / SICResearch

This sequence of maps, showing America turning from blue to red, elicited strong reactions on the Reddit forum where it was published last week. For some, the takeover by Fox News illustrates the demise of all that's good and fair about news journalism. Among the comments?

  • "The end is near."
  • "The idiocracy grows."
  • "(It's) like a spreading disease."
  • "One of the more frightening maps I've seen."
For others, the maps are less about the rise of Fox News, and more about CNN's self-inflicted downward spiral:
  • "LOL that's what happens when you're fake news!"
  • "CNN went down the toilet on quality."
  • "A Minecraft YouTuber could beat CNN's numbers."
  • "CNN has become more like a high-school production of a news show."

Not a few find fault with both channels, even if not always to the same degree:

  • "That anybody considers either of those networks good news sources is troubling."
  • "Both leave you understanding less rather than more."
  • "This is what happens when you spout bullsh-- for two years straight. People find an alternative — even if it's just different bullsh--."
  • "CNN is sh-- but it's nowhere close to the outright bullsh-- and baseless propaganda Fox News spews."

"Old people learning to Google"

Image: Google Trends

CNN vs. Fox News search terms (200!-2018)

But what do the maps actually show? Created by SICResearch, they do show a huge evolution, but not of both cable news networks' audience size (i.e. Nielsen ratings). The dramatic shift is one in Google search trends. In other words, it shows how often people type in "CNN" or "Fox News" when surfing the web. And that does not necessarily reflect the relative popularity of both networks. As some commenters suggest:

  • "I can't remember the last time that I've searched for a news channel on Google. Is it really that difficult for people to type 'cnn.com'?"
  • "More than anything else, these maps show smart phone proliferation (among older people) more than anything else."
  • "This is a map of how old people and rural areas have learned to use Google in the last decade."
  • "This is basically a map of people who don't understand how the internet works, and it's no surprise that it leans conservative."

A visual image as strong as this map sequence looks designed to elicit a vehement response — and its lack of context offers viewers little new information to challenge their preconceptions. Like the news itself, cartography pretends to be objective, but always has an agenda of its own, even if just by the selection of its topics.

The trick is not to despair of maps (or news) but to get a good sense of the parameters that are in play. And, as is often the case (with both maps and news), what's left out is at least as significant as what's actually shown.

One important point: while Fox News is the sole major purveyor of news and opinion with a conservative/right-wing slant, CNN has more competition in the center/left part of the spectrum, notably from MSNBC.

Another: the average age of cable news viewers — whether they watch CNN or Fox News — is in the mid-60s. As a result of a shift in generational habits, TV viewing is down across the board. Younger people are more comfortable with a "cafeteria" approach to their news menu, selecting alternative and online sources for their information.

It should also be noted, however, that Fox News, according to Harvard's Nieman Lab, dominates Facebook when it comes to engagement among news outlets.

CNN, Fox and MSNBC

Image: Google Trends

CNN vs. Fox (without the 'News'; may include searches for actual foxes). See MSNBC (in yellow) for comparison

For the record, here are the Nielsen ratings for average daily viewer total for the three main cable news networks, for 2018 (compared to 2017):

  • Fox News: 1,425,000 (-5%)
  • MSNBC: 994,000 (+12%)
  • CNN: 706,000 (-9%)

And according to this recent overview, the top 50 of the most popular websites in the U.S. includes cnn.com in 28th place, and foxnews.com in... 27th place.

The top 5, in descending order, consists of google.com, youtube.com, facebook.com, amazon.com and yahoo.com — the latter being the highest-placed website in the News and Media category.
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