Course of Theoretical Physics. Covers everything in several volumes from mechanics to statistical theory to quantum and relativity, all in a frighteningly mathematical framework that should appeal to the maths grad student. Enjoy!
Indeed. Around the lab, you smell things too. Does the air smell acrid? The house air is out and the floating tables have gone down. Does the air smell faintly rotten? There's vegetation in the laser cooling systems. Does the air smell like ozone? There's probably a short in the high voltage supply for the laser diodes. Burning cardboard? Some idiot has misaligned their laser and is burning a hole in their beam blocks. In complete agreement, people should never underestimate the power of smell, for ussing people, the surroundings or a mechanical/technological system.
Back before the ass fell out of Bell Labs, they paid their researchers $1K per provisional filed. Yes, that's "provisional". As a side note, in the lobby of the Murry Hill facility, they had a patent clock. When I visited a few years ago, the clock was up to over 26,000 (I forget the exact #) and had ticked over by a few by the end of my three hour lab tour. I heard numerous stories about people (during the hey-day) putting their kids through college exclusively on patent rewards. Might be part of why they're French and closed and now...
While technically achieved without wires, the thing with WiFi is that you can used the omnidirectional nature of the transmission (along with refraction and diffraction of the signal) to access the signal anywhere within its range, often without line of sight. Naturally, free space optics requires an uninterrupted line of sight and significant alignment procedures. Now I'm not saying line of sight networking is useless (it was used to great effect after 9/11 and is great for places you need a temp. network but can't string a wire) but comparing it to radio WiFi is a bit apples/oranges.
This kind of gorgeous tweaking gives me warm feelings inside. Shields has taken a common device used in the field and, through a deep understanding of the physics of its operations, has increased it's functionality without much additional complexity. From the paper he says he cools the device thermo-electrically to -30 deg. C. Thermo-electric cooling is far nicer than cryogenic cooling (typ. using liquid gasses for heat exchange) used in other devices for photon number counting. Further, the method only introduces electronic capacitance subtraction of the photodiode response which is relatively simple compared to other methods (e.g. http://www.stanford.edu/group/fejer/fejerpubs/2005/Langrock_OL_2005.pdf which uses the nonlinear response of a crystal and a massive amount of supporting optics and electronics). This subtraction gives orders of magnitude greater sensitivity and allows the time response of the initial avalanche to be extracted from which photon numbers can be counted. One of those wonderful, "why didn't I think of that", insights. Very nice.
Heh, my favorite statement from the monster cable ad:
"Nitrojen gas-injected cellular dielectric for extended frequency response."
That is, gas injection formed plastic. Just like every, other cable.
I'm going to get all the/. audiophiles offside with this, but whatever. Some of the stuff targeted at audio pimpers is truly ridiculous.
See
http://www.ilikejam.org/blog/audio/audiophile.html
For example:
The CD stop light pen: A giant disregard of optics leads people to believe that the probe light "goes somewhere in the CD" and needs to be trapped.
Audio-pimp cables: Yes, a good cable with decent materials and a well engineered, within spec connector will help with sound. Some of these audiophile connectors, however, provide no discernible or even measurable benefit. Certainly not for the cost required.
My favorite, the volume knob: A turned wooden knob. Ha ha, knob. This may be aesthetically pleasing to some, but to claim it has anything to do with audio quality is just wrong.
These audiophile things offend me. I realize some people like to mess with their hardware to make it look pretty in their eyes (ricers, for example) but to claim such "behind-the-scenes" hardware mods do anything except drain the bank accounts of the ignorant is beyond the pale and simply a scam perpetrated by those who know better.
As far as I can tell, from the article, it's DARPA lacking program managers that is the issue. A DARPA program manager allocates money, directs research within a program and decides if a particular group in the program is performing up to scratch. Sure, you have to be pretty well up on the state of the art in a fairly broad range of areas to succeed in doing this but, at the end of the day, you aren't actually doing any research. Working for DARPA is the scientific equivalent of middle management. Who gets into research to do that?
This impression is gathered from the giant sample set of one DARPA program manager I've have the pleasure of working with, so I may have a skewed view on the whole operation.
The light in photographs is (usually) the average power falling on an element, be it a CCD chip or a piece of silver halide salt in emulsion which interacts with the incident radiation over the timescale of many wavelengths. What these researchers are doing is "photographing" the individual wavefronts of a matter wave, rather than just the intensity information. Spatially resolving the so-called phase information of such a wave is no mean feat and is an area of current research in optics. Wakefields are a very cool plasma phenomenon in themselves, propagating with velocity near vacuum light speed in a medium. As user Gracenotes pointed out, the applications of wakefields can, due their very high electric fields, have potential for particle acceleration experiments. Especially so in hospitals where creating short-lived isotopes for procedures like positron emission tomography are desirable in ever smaller and ever more efficient machines. And don't get me started on a 30 TW laser. Frickin huge.....
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Course of Theoretical Physics. Covers everything in several volumes from mechanics to statistical theory to quantum and relativity, all in a frighteningly mathematical framework that should appeal to the maths grad student. Enjoy!
Indeed. Around the lab, you smell things too. Does the air smell acrid? The house air is out and the floating tables have gone down. Does the air smell faintly rotten? There's vegetation in the laser cooling systems. Does the air smell like ozone? There's probably a short in the high voltage supply for the laser diodes. Burning cardboard? Some idiot has misaligned their laser and is burning a hole in their beam blocks. In complete agreement, people should never underestimate the power of smell, for ussing people, the surroundings or a mechanical/technological system.
Back before the ass fell out of Bell Labs, they paid their researchers $1K per provisional filed. Yes, that's "provisional". As a side note, in the lobby of the Murry Hill facility, they had a patent clock. When I visited a few years ago, the clock was up to over 26,000 (I forget the exact #) and had ticked over by a few by the end of my three hour lab tour. I heard numerous stories about people (during the hey-day) putting their kids through college exclusively on patent rewards. Might be part of why they're French and closed and now...
While technically achieved without wires, the thing with WiFi is that you can used the omnidirectional nature of the transmission (along with refraction and diffraction of the signal) to access the signal anywhere within its range, often without line of sight. Naturally, free space optics requires an uninterrupted line of sight and significant alignment procedures. Now I'm not saying line of sight networking is useless (it was used to great effect after 9/11 and is great for places you need a temp. network but can't string a wire) but comparing it to radio WiFi is a bit apples/oranges.
This kind of gorgeous tweaking gives me warm feelings inside. Shields has taken a common device used in the field and, through a deep understanding of the physics of its operations, has increased it's functionality without much additional complexity. From the paper he says he cools the device thermo-electrically to -30 deg. C. Thermo-electric cooling is far nicer than cryogenic cooling (typ. using liquid gasses for heat exchange) used in other devices for photon number counting. Further, the method only introduces electronic capacitance subtraction of the photodiode response which is relatively simple compared to other methods (e.g. http://www.stanford.edu/group/fejer/fejerpubs/2005/Langrock_OL_2005.pdf which uses the nonlinear response of a crystal and a massive amount of supporting optics and electronics). This subtraction gives orders of magnitude greater sensitivity and allows the time response of the initial avalanche to be extracted from which photon numbers can be counted. One of those wonderful, "why didn't I think of that", insights. Very nice.
Heh, my favorite statement from the monster cable ad: "Nitrojen gas-injected cellular dielectric for extended frequency response." That is, gas injection formed plastic. Just like every, other cable.
These audiophile things offend me. I realize some people like to mess with their hardware to make it look pretty in their eyes (ricers, for example) but to claim such "behind-the-scenes" hardware mods do anything except drain the bank accounts of the ignorant is beyond the pale and simply a scam perpetrated by those who know better.
As far as I can tell, from the article, it's DARPA lacking program managers that is the issue. A DARPA program manager allocates money, directs research within a program and decides if a particular group in the program is performing up to scratch. Sure, you have to be pretty well up on the state of the art in a fairly broad range of areas to succeed in doing this but, at the end of the day, you aren't actually doing any research. Working for DARPA is the scientific equivalent of middle management. Who gets into research to do that? This impression is gathered from the giant sample set of one DARPA program manager I've have the pleasure of working with, so I may have a skewed view on the whole operation.
The light in photographs is (usually) the average power falling on an element, be it a CCD chip or a piece of silver halide salt in emulsion which interacts with the incident radiation over the timescale of many wavelengths. What these researchers are doing is "photographing" the individual wavefronts of a matter wave, rather than just the intensity information. Spatially resolving the so-called phase information of such a wave is no mean feat and is an area of current research in optics. Wakefields are a very cool plasma phenomenon in themselves, propagating with velocity near vacuum light speed in a medium. As user Gracenotes pointed out, the applications of wakefields can, due their very high electric fields, have potential for particle acceleration experiments. Especially so in hospitals where creating short-lived isotopes for procedures like positron emission tomography are desirable in ever smaller and ever more efficient machines. And don't get me started on a 30 TW laser. Frickin huge.....