Experimental Modern and Quantum Physics for Do-It-Yourself Science Enthusiasts 

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Welcome to diyPhysics.com !

Welcome to diyPhysics.com, a blog dedicated to the advanced do-it-yourselfer interested in modern and quantum physics!

David and Shanni PrutchiWe are the authors of the book Exploring Quantum Physics through Hands-On Projects,” which will help you understand Quantum Physics through hands-on experiments that you can conduct at school or at home!

Our book will guide you in the construction and use of setups to reproduce the key experiments that have brought us to our current understanding of the quantum world. Importantly, all of the experimental equipment can be built out of relatively inexpensive materials that are readily available at the hardware store or from on-line vendors of electronic surplus.

The projects range from simple measurements of Planck’s constant all the way to testing violations of Bell’s inequalities using entangled photons. The project descriptions are targeted to an audience with basic experience in electronic prototype construction. The circuits actually work, and the schematics are completely readable.

We hope that you enjoy reading our blog!

David and Shanni Prutchi

www.prutchi.com

 
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Modern/Quantum Physics Instructors: Adopt the Textbook

Teachers, instructors, and professors at accredited higher-learning institutions may request an evaluation copy of the book from J. Wiley & Sons.

 Shanni building and testing photoelectric effect setup

Why should you adopt this book as your Quantum Physics lab course textbook?

Our book explains Quantum Physics through hands-on experiments that the reader can perform at school. Throughout the book we guide the reader in the construction and use of setups to reproduce the key experiments that have brought us to our current understanding of the quantum world. Importantly, all of the experimental equipment can be built by the reader out of relatively inexpensive materials that are readily available at the hardware store or from on-line vendors of electronic surplus. Read more…

 
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$25 Philips Medical Systems PMTs from Sphere Research

Low-Cost Scintillation Probe Based on a Surplus XP3312 PMT for Ludlum Ratemeters www.diyPhysics.com prutchiSphere Research is clearing out all the Philips PMT assemblies they have in stock to empty their expensive off-site rental storage space. While stock is available, you can order any PMT shown as a Philips Medical Systems assembly at the beginning of this page for only $25 +shipping:

http://www.sphere.bc.ca/test/photo-tubes.html

Simply identify the deal as coming from DIY Physics when ordering (Note from diyPhysics.com: nothing in it for us except passing along some great info…).

All these tubes will be cleared out shortly so they can close down their over-priced off-site rental storage space. The offer is limited to stock on hand at the time of order. Sphere Research is happy to consolidate orders and help you minimize shipping costs wherever possible.  They can take Visa, MasterCard and PayPal for orders. These are very high performance tubes and hard to find, but they are very awkward for them to store in the big factory boxes, so they have to go.

 
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Reader-Built e/m Measurement System Showcased on YouTube

Javier De Elias Cantalapiedra from Madrid, Spain posted the YouTube video above to show the e/m measurement system that he put together based on the description in our book.  His measurement system is based on Hoag’s method, and his nicely laid-out setup allowed him to obtain very nice results (4 to 6% error compared to the theoretical e/m).

Javier is an industrial engineer who works in the telecommunications industry.  However, his passion is physics, which he pursues at a (very high) amateur level.

Thank you Javier for sharing!

 

 
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According to Quantum Mechanics…

 

 
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Quantum Mechanical Effects in Microgravity

Dorith and David Prutchi floating in zero g on board the "G Force One"

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/

 

 

 
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EG&G SPCM-AQR-13-FC Single Photon Counting Module on eBay (no relation to seller)

SPCM on eBay www.diyPhysics.comI 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.”

 
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Original Source for Flyback Driver Hack?

Flyback driver circuit from Radio Electronics September 1981 David Prutchi PhD www.diyPhysics.com

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:

High voltage AC driver for 250 kV DC power supply by David and Shanni Prutchi

Read more…

 
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Fair Sampling Loophole Closed for Test of Violation of Bell’s Inequality

 

Loophole-free Bell's Inequality Violation David Prutchi PhD www.diyPhysics.com

From “Loophole-free Einstein–Podolsky–Rosen experiment via quantum steering”, New Journal of Physics, Volume 14, May 2012

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.”

Read more…

 
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Loved the Book “How the Hippies Saved Physics” by David Kaiser

How the Hippies Saved Physics www.diyPhysics.com David Prutchi PhDI 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.

Read more…

 
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Air to Ground Quantum Key Distribution Achieved

Quantum key distribution from airplane David Prutchi PhD www.diyPhysics.com

From Nauerth et al, “Air to Ground Quantum Key Distribution”

From Phys.org:

“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.

Read more…

 
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Using Surplus Photonis XP2422/SN PMTs in Scintillation Probes

XP2422/SN PMT Photomultiplier David Prutchi PhD

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.

Read more…

 
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Schematics for Fast Pulse Amplifier for Macroscopic Entanglement Detection

Fast pulse amplifier for macro entanglement detectionA 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.

Read more…

 
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In Memoriam – Dr. Akira Tonomura (1942-2012)

photo_tonomuraWe 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.

Read more…

 
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Construction of a d.i.y. Thermoelectrically-Cooled Photomultiplier Tube (PMT) Housing

diy thermoelectrically cooled PMT housing David Prutchi PhD www.diyPhysics.com

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.

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diy Scintillation Probe for Ludlum Ratemeters Using Surplus XP3312/SQ PMT

 

Low-Cost Scintillation Probe Based on a Surplus XP3312 PMT for Ludlum Ratemeters www.diyPhysics.com prutchi

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.

Read more…

 
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diy Wu-Shaknov Experiment: Cheapest Demonstration of Quantum Entanglement?

diy Wu-Shaknov experiment by George Musser www.diyphysics.com

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.

Read more…

 
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