If there were any quantum effects to be seen, I wasn’t paying attention… Dorith (Mrs. diyPhysics) and I were having too much fun!
Click here for photos of Day 1 in the G Force One zero-g airplane
Click here for photos of Day 2 in the G Force One zero-g airplane
For more information about Zero G go to http://www.gozerog.com/
I HAVE NO RELATION TO SELLER – Just passing along in case someone is interested.
eBay item number 271206242864:
“The EG&G (or Perkin Elmer) SPCM-AQR is a self-contained module which detects single photons of light over the wavelength range from 400 nm to 1060 nm and sensitivity which often outperforms PMTs. The option 13-FC indicates 180 micron diameter Si APD, Dark Count < 250cps and FC connector attached.
I obtained this detector in working order five years ago and have not used it since then. The detector comes with two unknown optical fiber cables (one end: FC, the other end: bare fiber) and a supply cable to which you need to give 5V. No manual included. The US sale only.”
One of my all-time favorite circuits is the the following DC-to-AC inverter (click diagram to enlarge) based on an old color TV flyback:
A very interesting article by Bernhard Wittmann, Sven Ramelow, Fabian Steinlechner, Nathan K Langford, Nicolas Brunner, Howard M Wiseman, Rupert Ursin,and Anton Zeilinger, entitled “Loophole-free Einstein–Podolsky–Rosen experiment via quantum steering” appeared in the Nature’s New Journal of Physics, Volume 14, May 2012.
This paper describes a Bell’s Inequality Violation experiment in which the “fair sampling” loophole has been closed. This loophole posits the possibility that classical – rather than quantum – effects could be responsible for measured correlations between entangled pairs of photons in a Bell’s Inequality Violation experiment. The paper’s abstract reads:
“Tests of the predictions of quantum mechanics for entangled systems have provided increasing evidence against local realistic theories. However, there remains the crucial challenge of simultaneously closing all major loopholes—the locality, freedom-of-choice and detection loopholes—in a single experiment. An important sub-class of local realistic theories can be tested with the concept of ‘steering’. The term ‘steering’ was introduced by Schrödinger in 1935 for the fact that entanglement would seem to allow an experimenter to remotely steer the state of a distant system as in the Einstein–Podolsky–Rosen (EPR) argument. Einstein called this ‘spooky action at a distance’. EPR-steering has recently been rigorously formulated as a quantum information task opening it up to new experimental tests. Here, we present the first loophole-free demonstration of EPR-steering by violating three-setting quadratic steering inequality, tested with polarization-entangled photons shared between two distant laboratories. Our experiment demonstrates this effect while simultaneously closing all loopholes: both the locality loophole and a specific form of the freedom-of-choice loophole are closed by having a large separation of the parties and using fast quantum random number generators, and the fair-sampling loophole is closed by having high overall detection efficiency. Thereby, we exclude—for the first time loophole-free—an important class of local realistic theories considered by EPR. Besides its foundational importance, loophole-free steering also allows the distribution of quantum entanglement secure event in the presence of an untrusted party.”
I just finished the book “How the Hippies Saved Physics” by David Kaiser and absolutely loved!
The book was fun and immensely educational regarding the seemingly unlikely seed of modern-day quantum information theory. I must confess that when I first saw the book on the shelf at my local Barnes & Noble I dismissed it as yet another pseudo-scientific account of quantum physics. However, I bought a copy after reading the following review in New Scientist:
“David Kaiser’s How the Hippies Saved Physics is a reminder of the unexpected influence a bunch of freewheeling 1970s physicists had on fundamental theories
IT’S certainly a provocative title, but for the life of me I could not recall an era to which How the Hippies Saved Physics might have applied. Things made more sense, though, on reading David Kaiser’s mention of two other books, both of which had left a big impression on me: Fritjof Capra’s The Tao of Physics and Gary Zukav’s The Dancing Wu Li Masters.
“A team of German physicists has successfully demonstrated an ability to perform quantum key distribution (QKD) exchange between an airplane in flight and a ground station, paving the way perhaps to the same kinds of communications between satellites and ground stations which could lead to a global quantum based secure communications network. The team presented their results at the QCrypt convention this past week.
We prepared a short note on how to build a dynode voltage divider network for inexpensive surplus XP2422/SN photomultiplier tubes. The XP2422/SN PMT is especially suited for gamma-ray spectral analysis when coupled to a NaI(Tl) scintillation crystal because of its high pulse-height resolution (PHR). The XP2422/SN is available from Sphere Research in Canada.
A recent paper entitled “Displacing entanglement back and forth between the micro and macro domains” discusses the experimental possibility of displacing quantum entanglement into the domain where it involves two macroscopically distinct states, i.e. two states characterized by a large enough number of photons. Specifically, the authors describe the process by which they start with two entangled spatially separated optical modes at the single photon level and subsequently displace one of these modes up to almost a thousand photons.
With so many photons, it would be possible, at least in principle, to see entangled photon pulses with our eyes. This would also make it possible to perform entanglement experiments with linear coarse-grain detectors (NOT single-photon detectors).
Mathieu Stephan, a high speed electronics engineer at the Swiss quantum information systems company id Quantique SA (and prolific hardware hacker) designed the very fast pulse amplifiers needed to acquire signals from avalanche photodiodes for this experiment. He has posted a thorough description of his design on his blog: http://www.limpkin.fr.
We recently learned the sad news that Dr. Akira Tonomura – a truly great experimentalist – passed away on May 2, 2012 during the course of treatment on pancreatic cancer.
We have been great admirers of Dr. Tonomura. Our blog’s banner is a cartoon representation of an experimental setup developed by Dr. Tonomura, through which in 1986 he showed single-electron buildups of electron wave interference fringe patterns. This experiment clearly revealed the dual nature of electrons and was described by Physics World magazine as the world’s most beautiful physics experiment, ranking above the historical experiments of Galileo Galilei and Robert Millikan.
The photomultiplier tubes (PMT) is the workhorse detector in particle physics and many other fields that require detection of light at extremely low levels. However, the long-wavelength response of PMTs is not only low because of low quantum efficiency, but also because thermionic emission at room temperature causes swamps low-level signals with noise.
Reducing dark counts is especially important in photon-counting applications, especially when attempting to detect photons in the near-infrared. For example, the dark count of many PMTs rated for a wavelength range from 400 to 1200 nm, is in the hundred of thousands of counts when not cooled—making it virtually useless for detecting almost anything but the strongest signal. When cooled to -20 °C, the dark count is reduced to just a few tens counts. As such, in general, the use of PMTs that detect above 600 nm almost mandate a cooled housing.
We constructed a thermoelectrically-cooled housing to experiment with cooling a standard 2” face-on PMT. Although appropriate PMT noise reduction was achieved (one order of magnitude), the thermal efficiency of the do-it-yourself housing design was low, so lessons learned from this build will be used in a second-generation cooled housing.
Ludlum general-purpose ratemeters are professional-grade instruments that are available on the secondary market at affordable prices. They are compatible with a wide variety of probes, making them a great choice for educators, surveyors, and advanced amateur users. However, probes for Ludlum ratemeters are often as expensive as the meter instrument itself, making it worthwhile to build comparable versions from surplus components.
George Musser – an editor at Scientific American (and author of “The Complete Idiot’s Guide to String Theory”) – developed a diy version of the Wu-Shaknov Experiment. If George’s setup truly manages to measure the relative linear polarization of gamma rays from positron-electron annihilation, then he would have accomplished the most inexpensive demonstration of quantum entanglement!
The idea is to measure the relative linear polarization of gamma-ray photons emitted with opposite parity from the annihilation of positrons produced by the decay of Na-22 using Compton polarimetry and coincidence counting. The predicted results in the number of coincidences are different when assuming quantum entanglement than when basing the calculations on local hidden variables theories.
These are pictures of the Americium-241 sources inside some old Pyrotronics F3/5A smoke detectors that were being decommissioned. The activity of the Am-241 sources at the time of manufacture (1970s) totaled 80 µCi, so they should still have some ~70 µCi left in them.
The Pyrotronics F3/5A smoke detectors were manufactured in the early 1970s. The radioactive sources consist of americium oxide mixed with gold powder and formed into a small billet. This billet was then placed between a sheet of silver and a sheet of gold and rolled into a foil under high heat and pressure. Americium-241 decays primarily by alpha particle emission to neptunium-237, along with low energy gamma radiation, with a 59.5 keV gamma emission being most prominent.