Pi-Gang Luan's blog

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An interesting integral: \int^{\infty}_{-\infty} (sinx/x)^n dx (in Chinese)

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Poisson summation formula -- its proof and application (in Chinese)

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Feynman's trick II (in Chinese)

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Feynman's trick I (in Chinese)

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Lorentz Transformation - A very Brief Derivation


Here I give a very brief derivation of Lorentz Transformation.

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Why thin wire array behaves like a plasma medium? (Metamaterial of negative permittivity)

Anyone who had ever read Sir John Pendry's paper "Extremely Low Frequency Plasmons in Metallic Mesostructures" (Phs. Rev. Lett. 76,  4773 (1996)) may feel the arguement Pendry used for deriving the plasmon behavior is a little bit unclear. For example, Pendry replaced the canonical momentum (containing the qA term) of the electron inside the wire by an "effective kinetic momentum", which means the "effective electron" has a very large mass. The ambiguity can appear when integrating the H field to obtain a vector potential. Besides, the gauge freedom of the vector potential implies an additional uncertainty of the effective momentum. 

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Today is Pi day and Einstein's birthday, again!

Google's logo is very cute today !  

Today is defined as Pi day, it is also Albert Einstein's birthday. Besides, today is Japaness lover's "white day".

According to Wiki, "In the 1980s the Japanese National Confectionery Industry Association launched a successful campaign to make March 14 a "reply day", where men are expected to return the favour to those who gave them chocolates on Valentine's Day, calling it White Day for the color of the chocolates being offered."

 I have posted a blog one year ago to celebrate Einstein's birthday.

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My newest metamaterial paper: Power loss and electromagnetic energy density in a dispersive metamaterial medium

Phys. Rev. E 80, 046601 (2009) [5 pages](5 pages) -->
Power loss and electromagnetic energy density in a dispersive metamaterial medium

Pi-Gang Luan
Wave Engineering Laboratory, Department of Optics and Photonics, National Central University, Jhungli 320, Taiwan

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New paper: Cloaking of matter waves under the global Aharonov-Bohm effect

Cloaking of matter waves under the global Aharonov-Bohm effect


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Einstein's birthday, the PI day

The day before yesterday, Mar. 14 (3.14), was a great date, because Albert Einstein was born at the same day 130 years ago.

I and my wife enjoyed a very good holiday that day in Taipei. Most interestingly, we found a vivid statue of Einstein made by Ju Ming, stood still in front of the Chen-Ping (eslite) bookstore.

We took several photos around this statue. Here I share one of them with you.

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My Eprint papers


These are my Eprint papers. Some have already been published as Journal papers, some have not.

I will discuss some of them here someday.

You can link to  http://arxiv.org/ and search my name Pi-Gang Luan in Physics [arxive: All], and these papers would be shown to you. There is an exception, my YBE paper ([Colored solutions of Yang-Baxter equation from representations of U_{q}gl(2)] ). In that case you should type [Pi-Gang Luan] instead of Pi-Gang Luan to find the paper.

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My Chinese blogs and My Photonic Crystal Book


If you can read Chinese, you can visit my Chinese Blogs as follows.



Besides, I and my colleague (Prof. chen) published a Photonic Crystal book: "Photonic Crystals -- From butterfly wings to nanophotonics" in 2005.


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This is my first 2009 article

Now I come here again.

From now on I want to share with you my research experiences and personal opinion on  time dependent quantum system, photonic/sonic crystals, and metamaterials.  I would also like to write some articles on science teaching stuff.

I come from Taiwan. Usually I speak chinese, and have no many oppernituties to practice my English, so I wish someone can help me to improve my English. Thanks !



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Here is a good place


 It's the first time I visit here. I find here a wonderful place.



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