Tag Archives | Physics

Zuse’s Thesis – The Universe is a Computer

zusesthesis

Jürgen Schmidhuber writes:

Konrad Zuse (1910-1995; pronounce: “Conrud Tsoosay”) not only built the first programmable computers (1935-1941) and devised the first higher-level programming language (1945), but also was the first to suggest (in 1967) that the entire universe is being computed on a computer, possibly a cellular automaton (CA). He referred to this as “Rechnender Raum” or Computing Space or Computing Cosmos. Many years later similar ideas were also published / popularized / extended by Edward Fredkin (1980s), Jürgen Schmidhuber (1990s – see overview), and more recently Stephen Wolfram (2002) (see comments and Edwin Clark’s review page). Zuse’s first paper on digital physics and CA-based universes was:

Konrad Zuse, Rechnender Raum, Elektronische Datenverarbeitung, vol. 8, pages 336-344, 1967. Download PDF scan.

Zuse is careful: on page 337 he writes that at the moment we do not have full digital models of physics, but that does not prevent him from asking right there: which would be the consequences of a total discretization of all natural laws?

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Scientists Tame Schrodinger’s Cat

Because so many of you are Robert Anton Wilson fans, I just know you’re going to be excited that scientists are using Schrodinger’s Cat to create a new quantum computer, as reported by PhysOrg:

Physicists at the University of Sussex have tamed one of the most counterintuitive phenomena of modern science in their quest to develop a new generation of machines capable of revolutionizing the way we can solve many problems in modern science.

The strange and mysterious nature of quantum mechanics is often illustrated by a thought experiment, known as Schrӧdinger’s Cat, in which a cat is theoretically both dead and alive simultaneously.

According to a new study published this week in Physical Review A, Sussex physicists have now managed to create a special type of “Schrӧdinger’s” cat using new technology based on trapped ions (charged atoms) and microwave radiation.

Like the cat, the researchers made these ions exist in two states simultaneously by creating ‘entanglement’, an effect that challenges the very fabric of reality itself.

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New Half-Light Half-Matter Quantum Particles Created

Via ScienceDaily:

Prospects of developing computing and communication technologies based on quantum properties of light and matter may have taken a major step forward thanks to research by City College of New York physicists led by Dr. Vinod Menon.

In a pioneering study, Professor Menon and his team were able to discover half-light, half-matter particles in atomically thin semiconductors (thickness ~ a millionth of a single sheet of paper) consisting of two-dimensional (2D) layer of molybdenum and sulfur atoms arranged similar to graphene. They sandwiched this 2D material in a light trapping structure to realize these composite quantum particles.

“Besides being a fundamental breakthrough, this opens up the possibility of making devices which take the benefits of both light and matter,” said Professor Menon.

For example one can start envisioning logic gates and signal processors that take on best of light and matter. The discovery is also expected to contribute to developing practical platforms for quantum computing.

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Understand the Mysteries of Spacetime

New Adventures in Spacetime - Eleanor Knox

For the online-education-interested, the Institute of Art and Ideas has started updating their free online courses with short teaser videos that give a feel for what a course will be like.

One of these is “New Adventures in Spacetime“, a fascinating course by philosopher of physics Eleanor Knox from King’s College in London. Why not spend a few holiday hours wrapping our heads around what physicists talk about when they talk about spacetime?

The details of the course can be found here – or see the whole list of IAI Academy courses here.

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The Unreality of Time

violscraper via flickr

violscraper via flickr

Via Physics Central

Philosophy and physics may seem like polar opposites, but they regularly address quite similar questions. Recently, physicists have revisited a topic with modern philosophical origins dating over a century ago: the unreality of time. What if the passage of time were merely an illusion? Can a world without time make sense?

While a world without the familiar passage of time may seem far-fetched, big names in physics, such as string theory pioneer Ed Witten and theorist Brian Greene, have recently embraced such an idea. A timeless reality may help reconcile differences between quantum mechanics and relativity, but how can we make sense of such a world? If physics does indeed suggest that the flow of time is illusory, then philosophy may be able to shed light on such a strange notion.

British philosopher J.M.E McTaggart advanced this idea in 1908 in his paper titled, “The Unreality of Time.

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Quantum Physics Just Got Less Complicated: Wave-Particle Duality and Quantum Uncertainty Are Same Thing

Quantum physics says that particles can behave like waves, and vice versa. Researchers have now shown that this 'wave-particle duality' is simply the quantum uncertainty principle in disguise. Credit: Timothy Yeo / CQT, National University of Singapore; CC-BY

“Quantum physics says that particles can behave like waves, and vice versa. Researchers have now shown that this ‘wave-particle duality’ is simply the quantum uncertainty principle in disguise.”

Credit: Timothy Yeo / CQT, National University of Singapore; CC-BY

Via ScienceDaily:

Here’s a nice surprise: quantum physics is less complicated than we thought. An international team of researchers has proved that two peculiar features of the quantum world previously considered distinct are different manifestations of the same thing. The result is published 19 December in Nature Communications.

Patrick Coles, Jedrzej Kaniewski, and Stephanie Wehner made the breakthrough while at the Centre for Quantum Technologies at the National University of Singapore. They found that ‘wave-particle duality’ is simply the quantum ‘uncertainty principle’ in disguise, reducing two mysteries to one.

“The connection between uncertainty and wave-particle duality comes out very naturally when you consider them as questions about what information you can gain about a system.

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In the Beginning was the Code: Juergen Schmidhuber at TEDxUHasselt

The universe seems incredibly complex. But could its rules be dead simple? Juergen Schmidhuber’s fascinating story will convince you that this universe and your own life are just by-products of a very simple and fast program computing all logically possible universes.

Juergen Schmidhuber is Director of the Swiss Artificial Intelligence Lab IDSIA (since 1995), Professor of Artificial Intelligence at the University of Lugano, Switzerland (since 2009), and Professor SUPSI (since 2003).

He helped to transform IDSIA into one of the world’s top ten AI labs (the smallest!), according to the ranking of Business Week Magazine. His group pioneered the field of mathematically optimal universal AI and universal problem solvers. The algorithms developed in his lab won seven first prizes in international pattern recognition competitions, as well as several best paper awards.
Since 1990 he has developed a formal theory of fun and curiosity and creativity to build artificial scientists and artists.… Read the rest

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Is String Theory About to Unravel?

trailfan (CC BY 2.0)

trailfan (CC BY 2.0)

via Smithsonian:

In October 1984 I arrived at Oxford University, trailing a large steamer trunk containing a couple of changes of clothing and about five dozen textbooks. I had a freshly minted bachelor’s degree in physics from Harvard, and I was raring to launch into graduate study. But within a couple of weeks, the more advanced students had sucked the wind from my sails. Change fields now while you still can, many said. There’s nothing happening in fundamental physics.

Then, just a couple of months later, the prestigious (if tamely titled) journal Physics Letters B published an article that ignited the first superstring revolution, a sweeping movement that inspired thousands of physicists worldwide to drop their research in progress and chase Einstein’s long-sought dream of a unified theory. The field was young, the terrain fertile and the atmosphere electric. The only thing I needed to drop was a neophyte’s inhibition to run with the world’s leading physicists.

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2 Futures Can Explain Time’s Mysterious Past

In the evolution of cosmic structure, is entropy or gravity the more dominant force? The answer to this question has deep implications for the universe's future, as well as its past.  Credit: NASA; ESA; G. Illingworth, D. Magee, and P. Oesch, University of California, Santa Cruz; R. Bouwens, Leiden University; and the HUDF09 Team

In the evolution of cosmic structure, is entropy or gravity the more dominant force? The answer to this question has deep implications for the universe’s future, as well as its past.
Credit: NASA; ESA; G. Illingworth, D. Magee, and P. Oesch, University of California, Santa Cruz; R. Bouwens, Leiden University; and the HUDF09 Team

via Scientific American:

Physicists have a problem with time.

Whether through Newton’s gravitation, Maxwell’s electrodynamics, Einstein’s special and general relativity or quantum mechanics, all the equations that best describe our universe work perfectly if time flows forward or backward.

Of course the world we experience is entirely different. The universe is expanding, not contracting. Stars emit light rather than absorb it, and radioactive atoms decay rather than reassemble. Omelets don’t transform back to unbroken eggs and cigarettes never coalesce from smoke and ashes. We remember the past, not the future, and we grow old and decrepit, not young and rejuvenated.

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Researchers use real data rather than theory to measure the cosmos

Incase (CC BY 2.0)

Incase (CC BY 2.0)

via Phys.org:

For the first time researchers have measured large distances in the Universe using data, rather than calculations related to general relativity.

A research team from Imperial College London and the University of Barcelona has used data from astronomical surveys to measure a standard distance that is central to our understanding of the expansion of the .

Previously the size of this ‘standard ruler’ has only been predicted from theoretical models that rely on general relativity to explain gravity at large scales. The new study is the first to measure it using observed data. A standard ruler is an object which consistently has the same physical size so that a comparison of its actual size to its size in the sky will provide a measurement of its distance to earth.

“Our research suggests that current methods for measuring distance in the Universe are more complicated than they need to be,” said Professor Alan Heavens from the Department of Physics, Imperial College London who led the study.

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