Month: March 2015

March 15, 2015 ScienceEveryday (medical imaging is separate) Post a Comment

Happy Pi Day courtesy of Richard Green.

Happy Pi Day courtesy of Richard Green. 

This post reminds me of the memory palace memorization technique. You can read/learn more here:

The Secrets of Sherlock’s Mind Palace via Smithsonian.com

http://goo.gl/LxeaFR

TED talk, Feats of memory anyone can do

http://goo.gl/N2k5fl

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Originally shared by Richard Green

How to remember 100,000 digits of pi

The retired Japanese engineer Akira Haraguchi (1946–) claims to hold the world record for reciting the most memorized digits of the number pi. He set the record starting at 9am on October 3, 2006, and reached digit number 100,000 at 1.28am on October 4, 2006. 

The event was filmed in a public hall near Tokyo. Haraguchi took 5-minute breaks to eat every two hours, and even his trips to the toilet were filmed to prove that the feat was genuine. This broke Haraguchi’s previous record of 83,431 digits, which he performed from July 1–2, 2005.

The reason I say that Haraguchi claims to hold the record is that, for some reason, the Guinness World Records organization has failed to recognize this achievement, despite the existence of witnesses and detailed documentation. The Guinness-recognized record for reciting pi is 67,890 digits by Lu Chao, a 24-year-old graduate student from China, who recited the digits, without error, in 24 hours and 4 minutes.

Haraguchi’s technique for memorizing long lists of numbers is quite interesting. He assigns kana characters to each number, each of which represents a Japanese syllable. In his system, the digit 0 can be read as o, ra, ri, ru, re, ro, wo, on or oh; the digit 1 can be read as a, i, u, e, hi, bi, pi, an, ah, hy, hyan, bya, or byan; and there are analogous rules for the other digits.

Using this system, Haraguchi has created many stories and poems, including a story about the 12th century hero Minamoto no Yoshitsune. The first 15 digits of pi, which are 3.14159265358979, are rendered in Haraguchi’s system as the words saishi ikokuni mukosan kowakunaku, whose approximate meaning is “the wife and children have gone abroad; the husband is not scared.”

Given all this, it may be surprising to learn that as a child, Haraguchi was neither a prodigy nor a mathematical genius. On the contrary, one of his teachers once made him stand to attention in the hallway as a punishment for badly failing to memorize multiplication tables of one-digit numbers.

Relevant links

Akira Haraguchi: http://en.wikipedia.org/wiki/Akira_Haraguchi

Minamoto no Yoshitsune: http://en.wikipedia.org/wiki/Minamoto_no_Yoshitsune

The Kana writing system: http://en.wikipedia.org/wiki/Kana

A 2006 article from the Japan Times about Haraguchi: http://goo.gl/d4H2pB

It looks as if the article’s URL may change at some point, so you may want to Google the article’s title instead: How can anyone remember 100,000 numbers?

The web site http://pi-world-ranking-list.com/ maintains a list of records of reciting from memory digits of the irrational numbers pi, e, and the square root of 2.

Picture credit: Travis Morgan

Picture source and associated poem: https://www.flickr.com/photos/morgantj/5575500301/in/photolist

#mathematics #piday  

March 4, 2015 ScienceEveryday (medical imaging is separate) Post a Comment

Quantum hype

Quantum hype

Thanks Brian Koberlein for explaining this way better than I could. Once again, the media takes some interesting science news and runs with a few misconceptions.

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Originally shared by Brian Koberlein

Two for One

There’s been much buzz about a new paper claiming that it’s observed light acting as both a particle and a wave at the same time. Is this legitimate research? Yes, absolutely. Did they actually observe particles and waves at the same time? Well…

Much of the hype around this paper is driven by some basic misconceptions regarding quantum objects. The popular view of quantum theory is that things like photons are sometimes particles and sometimes waves, and which one they become depends upon how you observe them. But in fact quantum objects are neither particles nor waves. They are quanta, which is a separate thing altogether. Under the right conditions quanta can demonstrate wave-like and particle-like behaviors, and there is complementarity between them so that quanta tend to lean toward one or the other in an experiment. But within the formalism of quantum theory, particle-wave duality is a property of the quanta as a whole. Thinking of quanta as particles or waves is far to simplistic when dealing with quantum theory. This is important to keep in mind when popular articles such as this hit the web.

As research areas such as quantum optics and quantum computing developed, we’ve gained tools to really start looking at sophisticated quantum interactions. It’s how we’ve been able to study things like the connection between the uncertainty principle and entropy, or study phase velocity in a quantum system. But since this kind of work isn’t easy to describe in simple terms, it gets hyped as “quantum mechanics gets simpler!” or “speed of light not absolute!” The same is the case here.

So what’s really going on in this work? The team pulsed laser light at a tiny wire of conductive material (a nanowire). The light induced what is known as surface plasmon polaritons in the nanowire, which is basically an electromagnetic wave pattern within the electrons of material. Because of the size of the nanowire, the plasmon polaritons form a standing wave within the wire, which is where the “wave” aspect comes into the experiment. They also radiate light, which in a quantum sense means that photons are emanating from this standing wave. The team then aimed a beam of electrons at the set up. Some of the electrons collided with the emanating photons, and thus gained some energy. Since these collisions are particle-like, they gain specific (quantized) energy amounts from the induced photons.  Basically the team found a way to induce particle-like interactions while maintaining the overall wave aspect of the system at the same time.

Does this mean the team caused a specific photon or electron to behave as a particle and wave at the same time? No. The particle interactions with the electrons and the induced wave pattern in the wire are two separate aspects of the system. But their result is useful because it could allow us to study quantum interactions directly. This type of work is really useful for photonics and quantum computing, and it’s a clever way to interact with quantum systems.

But this is not an experiment that somehow violates quantum theory. We’ve known for a while that we should be able to do this kind of thing in theory. The achievement here is that they actually pulled it off.

Paper: L Piazza, et al. Simultaneous observation of the quantization and the interference pattern of a plasmonic near-field. Nature Communications 6:6407 DOI: 10.1038/ncomms7407 (2015)

https://briankoberlein.com/2015/03/04/two-for-one/