Tag Archives: physics

Home Experiments: Quantum Erasing

Do your own experiment on quantum erasing – Quantum Erasing in the Home (for instructions). From the accompanying article, A Do-It-Yourself Quantum Eraser:

The light patterns that you will see if you conduct the experiment successfully can be accounted for by considering the light to be a classical wave, with no quantum mechanics involved. So in that respect the experiment is a cheat and falls short of fully demonstrating the quantum nature of the effect.

Nevertheless, the individual photons that make up the light wave are indeed doing the full quantum dance with all its weirdness intact, although you could only truly prove that by sending the photons through the apparatus and detecting them one at a time. Such a procedure, unfortunately, remains beyond the average home experimenter.

CERN Pressure Test Failure

photo of Femilab inner triplet quadrupole at CERN

On March 27th a high-pressure test at CERN of a Fermilab-built ‘inner-triplet’ series of three quadrupole magnets in the tunnel of the Large Hadron Collider failed. Fermilab Director on the test failure:

We test the complex features we design thoroughly. In this case we are dumbfounded that we missed some very simple balance of forces. Not only was it missed in the engineering design but also in the four engineering reviews carried out between 1998 and 2002 before launching the construction of the magnets. Furthermore even though every magnet was thoroughly tested individually, they were never tested with the exact configuration that they would have when installed at CERN–thus missing the opportunity to discover the problem sooner.

We need and want to make sure that we find the root causes of the problem and from the lessons learned build a stronger institution. Beyond that, there is no substitute for the commitment each of us makes to excellence, to critical thinking and to sweating every detail.

In a Fermilab Update on Inner Triplet Magnets at LHC they state: “The goal at CERN and Fermilab is now to redesign and repair the inner triplet magnets and, if necessary, the DFBX without affecting the LHC start-up schedule. Teams at CERN and Fermilab have identified potential repairs that could be carried out expeditiously without removing undamaged triplet magnets from the tunnel.”

Slowing Down Light

Putting the Brakes on Light Speed:

The achievement is the latest in the fast-paced field of “slow light” — a discipline that barely existed a decade ago. While other researchers have dragged light to slower speeds than the Rochester scientists, who got it down to one-three-hundredth of its normal velocity, the new method is far simpler. That means the dream of domesticating one of nature’s most feral forces for use in computing, image processing and a host of military and homeland security applications could be nigh.

“This is a big step toward bringing slow-light technology into practical usage,” said Steve Harris, a professor of electrical engineering and applied physics at Stanford University. As the fleetest form of energy in the universe, light has the potential to revolutionize a wide range of technologies. Pulses of light can substitute for the digital “ones” and “zeros” that are today conveyed by relatively massive electrons on silicon chips.

So, You Want to be an Astrophysicist?

Dynamics of Cats (good name don’t you think) has an interesting series of posts: So, you want to be an astrophysicist? The latest is: Part 2.5 – grad school by Steinn SigurÃ°sson:

Think very seriously about whether you want to do theory, observation, data analysis or instrumentation.
You may end up doing things you never imagined out of necessity (like theorists go take observations, cause if they don’t no one else will; or observers running simulations, or building the instrument they need to do the observations etc etc).
…
Finally: READ!!! Pro-actively.
Check arXiv regularly and thoroughly. Read the papers relevant to you and anything else that looks interesting.
Read the references! They are there for a reason. Read the citations – if a paper is interesting, papers which cite it are also likely to be interesting. Use the ADS “C” option liberally and look through it quickly. If in doubt ask you advisor, or just read it anyway.

Next, the slightly tricky issue of what we actually “do”, research wise type of thingy. Might take a while…

arXiv.org is a (even the) great open access article resource. “Open access to 400,419 e-prints in Physics, Mathematics, Computer Science and Quantitative Biology.”

Cool Mechanical Simulation System

Cool device from MIT: A Shrewd Sketch Interpretation and Simulation Tool.

We aim to create a tool that allows the engineer to sketch a mechanical system as she would on paper, and then allows her to interact with the design as a mechanical system, for example by seeing a simulation of her drawing. We have built an early incarnation of such a tool, called ASSIST, which allows a user to sketch simple mechanical systems and see simulations of her drawings in a two-dimensional kinematic simulator.

via: Back to the Drawing Board

Science Education in the 21st Century

Photo of Dr. Carl Wieman

Science Education in the 21st Century: Using the Tools of Science to Teach Science podcast by Dr. Carl Wieman, recipient of the Nobel Prize in Physics in 2001. Also received the first NSF Distinguished teaching Scholars award (NSF’s “highest honor for excellence in both teaching and research”) and the National Professor Of The Year (CASE and Carnegie Foundation).

Dr. Carl Wieman, recipient of the Nobel Prize in Physics in 2001, discusses the failures of traditional educational practices, even as used by “very good” teachers, and the successes of some new practices and technology that characterize this more effective approach. Research on how people learn science is now revealing how many teachers badly misinterpret what students are thinking and learning from traditional science classes and exams.

However, research is also providing insights on how to do much better. The combination of this research with modern information technology is setting the stage for a new more effective approach to science education based on using the tools of science. This can provide a relevant and effective science education to all students.

Podcast recording 21 Nov 2005 at the University of British Columbia.

Text of March 15, 2006 Dr. Wieman testimony to the US House of Representatives Science Committee.

Nobel Laureate Joins UBC to Boost Science Education

via: Maintaining scientific humility

Quantum Mechanics Made Relatively Simple Podcasts

Three Lectures by Hans Bethe

In 1999, legendary theoretical physicist Hans Bethe delivered three lectures on quantum theory to his neighbors at the Kendal of Ithaca retirement community (near Cornell University).

Intended for an audience of Professor Bethe’s neighbors at Kendal, the lectures hold appeal for experts and non-experts alike. The presentation makes use of limited mathematics while focusing on the personal and historical perspectives of one of the principal architects of quantum theory whose career in physics spans 75 years.

Florida State lures Applied Superconductivity Center from Wisconsin

Ching-Jen “Marty” Chen, dean of the College of Engineering, and Chiang Shih, chairman of the college’s department of mechanical engineering, also were heavily involved in negotiations to bring ASC to FSU.

“The College of Engineering joins the National High Magnetic Field Laboratory in welcoming the move of the Applied Superconductivity Center to Tallahassee,” Chen said.

“This is an excellent example of multidisciplinary collaboration between the sciences and engineering. The affiliation of ASC with the College of Engineering amplifies many ongoing efforts in material engineering research in the college and the magnet lab.”

Four top ASC researchers, including Director David C. Larbalestier, will begin relocating by January 2006. They will be followed over the next six months by eight post-doctoral researchers, several highly skilled machinists and a few graduate students. In all, ASC may bring as many as 30 researchers to Tallahassee, along with some $2 million in research grants and another $2.5 million worth of precision laboratory equipment.

Larbalestier is viewed by many of his peers as the leading researcher in the United States, and possibly the world, in the basic research of practical superconducting materials for magnets and power applications. Over a 35-year career, he has profoundly influenced the development of high-field magnets for high-energy physics and other applications, such as magnetic resonance imaging (MRI), that have evolved from them. Among the highlights of his career is his election in 2003 to the prestigious National Academy of Engineering.

“The Economic Development Council of Tallahassee/Leon County (EDC) is excited with this impressive level of investment and ongoing million-dollar payroll that will leave a lasting and positive influence on our regional economy,” said Brad Day, executive director of the ECD. “With the recruitment of research and development activities like this, our community continues to earn its reputation as a technology-rich economy.”

On the ASC site, hosted at Madison, they don’t spin the story quite the same way – Breaking News: ASC will be teaming up with NHMFL in Tallahassee, FL in 2006. Still that headline links directly to the FSU news release.