Tuesday, June 30, 2015

4 Common Misconception About Quantum Physics

I've been critical of several physics article that have appeared in Epoch Times, many of them verging on crackpottery. But I have to admit, this one is actually quite good. It details 4 important misconception that came out of QM.

My summary of these misconceptions are:

1. Quantum entanglement transfers information faster than c.

2. Consciousness is necessary to "collapse" wave-function.

3. QM is only valid at the subatomic level.

4. Wave-particle "duality".

You may read the article to get the details, but for an article designed for the general public, it is actually quite accurate and understandable.


Wednesday, June 24, 2015

Gravitational Lensing

Here's a simple intro to gravitational lensing, if you are not familiar with it.


Friday, June 19, 2015

Quantum Superposition Destroyed By Gravitational Time Dilation?

This is another interesting take on why we see our world classically and not quantum mechanically. Gravitational time dilation is enough to destroy coherent states that maintain superposition.

With this premise, the team worked out that even the Earth's gravitational field is strong enough to cause decoherence in quite small objects across measurable timescales. The researchers calculated that an object that weighs a gram and exists in two quantum states, separated vertically by a thousandth of a millimetre, should decohere in around a millisecond. 

I think this is similar to Penrose's claim that gravity is responsible for decoherence of quantum states. It will be interesting if anyone can experimentally verify this latest theoretical finding.


Thursday, June 11, 2015

July Is The Least Popular Month For Physics

I did not know that!

The Buzz Blog at the APS Physics Central has a very interesting statistics on popularity of the word "physics" on Google search, and it showed a prominent pattern of large, yearly dip in July!

July is the least popular month for physics, marking the bottom of a decline that starts in May. This is not really surprising given that schools in the Northern Hemisphere tend to finish in May or June, and that July is the most popular month for vacations for Americans. Physics is definitely an academic term and it makes sense that its popularity aligns with students and researchers working to the academic calendar. Other academic terms such as "literature", "economics", and "math" also have minimum online interest during July. "Surfing", on the other hand, has a peak interest in July.

This means that right now, the date that this blog entry is posted, is the beginning of the downtrend. I won't blame you guys if the number of hits and read of this blog takes a strong dip starting now! :)


Wednesday, June 10, 2015

How You Ask A Test Question May Impact A Student's Performance

When I first read this, I must say that I was not totally surprised by its results and conclusions.

This study was done on a group of female students at the University of Cambridge. In the study, they asked practically the same type of question, covering the same material, but in different ways. The students seem to do better when answering the questions when the "... questions are scaffolded...", i.e. it asked the students to answer one piece at a time, leading to the final answer (see the example in the paper. The paper is open access, so you should be able to get a copy of it.).

I find that one of the most common issues when students are given an entire problem in one shot is that they don't know where to start. They have all of these information swirling in their heads, and they don't know which one to use and applicable to answer the question. So having this "scaffolding", where the question asked for something obvious, and then lead the student to another level, certainly might help in guiding the student towards the final answer.

I remember my time as an undergrad at UW-Madison, taking an E&M class with Prof. Bernice Durand, that she had a unique form of assistance during her exams. She actually told us that if we got stuck, or can't answer a question, we could walk up to her during the exam, and asked for hints. Then, depending on the question, she might write something either as a hint, or something to start off. Depending on how much help she gave, the student won't get credit for knowing that part of the solution, but at least, might be able to continue and solve the rest of the problem. She told us that this way, both she and student can diagnose the source of the problem (i.e. say the student just didn't know where to start, but once that is solved, the student was able to carry out the rest of the solution),

I think this is a similar idea to this study. So as someone who benefited from this structure, I can understand how a student might do better when questions are framed like that.


Sunday, June 07, 2015

The Philosophy of the LHC

This is actually a nice article, and unlike other "confrontational" issues with regards to Physics and Philosophy, it addresses areas in which Philosophy can actually be of use in Physics, but not in the usual sense that have been tossed around.

There have been many tedious and futile discussions about the value of philosophy for modern science. I find it much more interesting and fruitful to ask if and in what way modern science can advance philosophy. The complexity, the new challenges and the new methods that arise in modern science in general - and at the LHC in particular - raise a number of questions that concern core issues of philosophy of science: what are the methods of acquiring knowledge, what is the role of models, and how does the intricate relationship between theory, computer simulations and experimental data work? The LHC has been built for fundamental physics, but it will also challenge and advance the philosophy, sociology and history of science!

We don't hear much about this aspect, mainly because it isn't "sexy". But this is a unique and useful convergence, and with physics opening up a myriad of discoveries that have changed our world view, there's nothing wrong with philosophy being guided by such discoveries.


Friday, June 05, 2015

LHC at 13 TeV - Where Are The Crackpots Now?

I taunted the doomsday crackpots when the LHC hit 8 TeV a while back, and I'm going to taunt then again now. So where are these jokers hiding and what are their excuses for our world still had not been swallowed up by a gigantic blackhole created by the high-energy collisions?

Now granted that the last thing I want to do is hear any more nonsensical ramblings from these folks. They've take up too much oxygen already in their lifetimes. But still, I sometime wish I can come across one of them, and really, REALLY, ask them if they think that they have a huge egg on their faces. There is just not enough follow-up on things like this, and I often wonder if these people actually learned something from their silliness, or if they are still delusional and stubborn about it.

At some level, the same can be said about all those preprints and theories that came out when OPERA reported faster-than-light neutrinos. I sometime wish I could talk to these people, who I don't consider to be crackpots, but who should know better than to jump the gun. I always wanted to know why they publish their theories THAT quickly to jump on the bandwagon. Is it the idea of wanting to be the first? Is it the concept of throwing out as many darts as one can and hope that one will stick? How do they feel now that they somehow came up with a theory based on a non-existing evidence?

So many questions, and so little time to find out the answers.


Thursday, June 04, 2015

Why Do We Plot Our Data?

I stumble upon this Rhett Allain's article on Wired on the importance of plotting data, especially in experiments, and it reminded me of a similar document that had been used for quite a while at the Illinois Institute of Technology for their undergraduate physics labs.

I think both of them had the same idea and the same emphasis. Graphing and being able to know how to use it to analyze data is something that isn't normally taught in a physics class, and that is a shame, because it is an essential part of connecting experimental data to a "theory" or theoretical model. This is where the experiment and the theory meet! It is also where we can analyze how "reliable" or how much confidence we have on what we measure. This is important because when we do not have 100% certainty, we need to know when something is good enough to be accepted.

These are skills and knowledge that many are not exposed to, and it is sad that science classes, especially those involved with experiments, do not put more emphasis on such things.