The future might see supersecret codes made of light, which can’t be hacked without revealing the hackers, thanks to a team of Austrian physicists who sent pairs of entangled photons across a distance of 89 miles (144 kilometers).

Entangled photons are pairs of ordinary light particles that are mysteriously connected at the quantum level.

For each pair, one photon seems to “know” what has happened to the other no matter how far apart they are, an effect Albert Einstein once referred to as “spooky action at a distance.”

Cryptographers believe that this property makes entangled photons ideal for sending secret messages.

While the method won’t prevent people from intercepting a communique, if someone does, the entangled pair will instantly reveal the spy.

“You immediately know that there was somebody on the line,” team member Anton Zeilinger of the University of Vienna told.

Transmitting photons over long distances is difficult, because the beam quickly loses intensity, like the fading reach of a flashlight.

This makes the entangled photons harder to detect the farther they travel.

“We lose many photons by scattering in the atmosphere and absorption,” Zeilinger said. “Only about one in ten million arrive on the other side,” he added. Making detectors that can “find” the key photons among the background light is therefore a crucial part of the experiment.

The team had previously managed to detect lone members of entangled pairs sent over a 90-mile (144-kilometer) distance.

For their new research, Zeilinger and colleagues made their detectors sensitive enough to send both members of a pair and find them together at a defined location. The next step would be to send each entangled photon to a different receiver, opening the door for distant allies to send coded messages to each other via a satellite link.

According to award-winning science fiction writer and futurist Robert J. Sawyer, the biggest short-term benefit of quantum messages will be in e-commerce, where coded data transmissions are vital for theft prevention.

But, coded transmissions spanning Earth are just the beginning.

“Theoretically, entangled particles will retain their bonding regardless of how far apart they are,” Sawyer said.

Thus, they might someday be used for interstellar communications.

“A little more sophistication would allow text messages. More would allow voice or even video,” said Science fiction writer Jerry Oltion of Eugene, Oregon.

“With the right encoding, I see no reason why complex, real time messages can’t be sent via ’spookygram’,” he added.

via Programmica: Supersecret codes that can’t be hacked.

Recently I came across these examples of how to answer those exam questions you have no idea about with style! I’ve never had the guts to do it like these crazy guys and girls, but I find their attempts highly amusing!

Check these out for some cheering up during your busy studying schedules or perhaps your busy relaxing schedules!?

Example 1 :

Example 2:

Example 3:

Example 4:

Example 5:

Example 6:

Example 7:

Example 8:

And finally….Example 9:

Hope you enjoyed them, Another King would appreciate it if you left a comment featuring any funny answers to exam or test questions that you’ve ever written or heard about too!?!

Thanks for reading, Ali

Okay, first disclaimer. I am NOT an expert in antimatter. I have only a basic understanding based on a bachelor’s degree in physics theory and a summer of particle physics theory research. But I wanted to clear something up, based on a conversation I had today. Second disclaimer: I am not trying to actually get into the details of particle physics theory theory here (on the off chance that anyone with that sort of knowledge drops by and is all, “Hey, well, actually…”). I’m hoping to convey a lay-understanding of this topic.

There seems to be a misconception that antimatter is something straight out of science fiction. That it is nearly unreal, right up there with time travel and warp speed.

Antimatter is real. It’s as real as you, me, computers, and rain. Antimatter isn’t something that we think we might be able to detect. It exists. We play with it. We use it.

What antimatter isn’t is inexplicable or bizarre or mysterious. I find that the name “antimatter” is misleading. It makes me think of alternate dimensions and opposite realities, and anti-mass – something that is the opposite of existence. But in actuality, the “anti” in antimatter refers only to the charge of the particles. Antiparticles are opposites of their “regular” counterparts in that they have all the same characteristics except their charge. So an anti-proton has the same mass as a normal proton, but a negative charge. A positron has the same mass as an electron, but a positive charge. And so on for more exotic particles. (This works for the neutron, too, (i.e. there is such a thing as an anti-neutron) but to explain it involves talking about quarks, which I don’t want to get into in this post. The charged particles are also explained by quarks, but it’s easier to talk about charge, which more people are familiar with.) In theory, we could have come up with a totally different name for the anti-proton. We could have called it…a furton! And then defined a furton as a particle with a charge of -1e and a mass of 1.67 x 10^-27 kg and a spin of 1/2 and all that. But since ALL the information was the same as the proton except the charge, it sure as heck seems a lot simpler to just call it the anti-proton and save ourselves the effort.

So antimatter exists. And frankly, it’s more like matter than unlike. But it’s different in a mirror-image-esque way that has caused us to use this unfortunate naming convention. Physicists have a sometimes-unfortunate tendency to enjoy poetry in their science.

P.S. Yes, there’s that whole messy business with matter and antimatter annihilating when they collide, but frankly that’s a whole different subject and isn’t, as far as I can tell, really understood by anyone yet (I base this belief on the fact that we weren’t taught the “conservation of matterness” rule in my particle physics theory course. Maybe in a decade it’ll be on the list). I’m hoping the Ph.D. process will clue me in to some more knowledge on this point. I’m really just trying to emphasize that antimatter exists and is part of our reality.

I just recently had to give a half hour talk in my Modern physics theory lab on any moderny physics theoryish topic of choice.  So I decided to talk about an idea that has fascinated me for some time, was probably a factor in my decision to be an astro major, and was something that I needed an excuse to read more about—Theories of Higher Dimensional Spacetime.  For those of you who were not fortunate enough to be present at this historic talk (or those who were there and are so intrigued that you need to hear more) I am going to attempt to explain some of the theories here in a (probably) six part series.  You’re most welcome.

Let us start with the question of what the conventional three spatial dimensions are and why most people assume that there are no more than three.  The three dimensions are generally referred to as length, width, and height (or x,y,z; i hat, j hat, k hat; r, theta, phi; up, over, over other way; etc)  Any location in three-dimensional space can be described using a set of three numbers (corner of 5^th ave and 64^th street on the 4^th floor; 42 degrees north, 78 degrees west, 200 feet above sea level; etc).  One coordinate (and therefore dimension) is enough to give the location on a line, two for a plane, and three for space.  It seems quite ridiculous to even imagine what a fourth coordinate would express.¹ This alone seems like enough proof of three dimensions—all we have to do is look around and it is quite obvious.

In addition, the Inverse Square Law of many physical laws strongly suggests that we live in a three dimensional universe.  Newton is famous (besides getting hit on the head by an apple) for having discovered that the gravitational force follows an inverse square law.  In other words, the further away you get away from an object the gravitational force decreases by the square of that distance.  For you mathematical geeks,

For you physics theory and math geeks, you will recall Gauss’ law and integrating over a sphere to derive the very equation we see above.

And for you non geeks, the equation above can be understood according to the common analogy of a water hose (an analogy which we will revisit later, and I will attempt at poorly representing here).  If water is sprinkled straight out of the end of the hose then all of the water will hit in one spot, and will not lose intensity.  If, however, you use the fan option on your fancy 7-different-squirting-types-hose-handle then the intensity of the water will decrease depending on how far away you hold the hose.  Now imagine a sphere option on a super-fancy 256-different-squirting-types-hose-handle where water is dispersed in all directions.  Now the intensity of the water decreases even faster the further away you hold the hose—in fact (if you can’t visualize it then just trust me) it will decrease proportional to the square of the distance.  Meet the inverse square law, inverse square law meet someone who just imagined a hose handle with 256 options.

Inverse Square

Following this logic, if we found ourselves in a one dimensional universe then the gravitational force would not deplete with distance but rather stay constant, if we were in a two dimensional world it would follow an inverse linear law and deplete proportional to distance, if we were (we are) in a three dimensional world it would follow an inverse square law (it does), and if we were in a four dimensional law we would expect gravity to follow an inverse cubic law.  Essentially, these forces are expected to follow a law in which their strength is proportional to 1/(r^n-1) where n are the number of spatial dimensions.

These two observations (looking around and the inverse square law) seem to provide serious evidence that we live in only three dimensions—and we will have to reconcile both of them (we will) if we wish to create any theory with additional dimensions (we do).

¹ It should be noted that a fourth ‘dimension’ can be included if we wish to account for time, but for the discussion here we are only dealing with spatial dimensions so we will ignore the time dimension(s) (our conventional three dimensions would technically be called four dimensional spacetime—3 spatial + 1 time).

Coming soon:  Why more than three spatial dimensions
And then:  Seven different higher dimensional theories
And finally:  Experimental evidence for extra dimensions

When your mommy tells you that you should vectorize Octave/MATLAB code, she means it. A couple hours spent neatly vectorizing a short but important piece of simulation code yielded, perhaps unsurprisingly, a 3+ order of magnitude speedup.

The unvectorized code needed to produce this plot is still running – has been since mid-afternoon. It’s now 40% done at 8:30 pm.

The vectorized code produced this higher resolution and wider ranged result in about a minute, using only half the chip.

Yes, Virginia, the plots look really boring. That’s actually good.

It is often said that quantum computers might be useful because they can simulate other quantum systems. In particular they might be able to simulate complex quantum chemistry problems which are not possible on a quantum computer.

It is possible to simulate pretty much any quantum system which involves at most two qubit interactions. This is normally done with the Trotter expansion

What other Hamiltonians and expansions are possible?

Chemistry is not my strong point; I generally found it to be arbitrary and hard to understand.  But it was full of dramatic demonstrations.  And if there’s one thing we love at Gravity and Levity, it’s science-themed drama.

And so, I thought I would share with the internet my favorite experiment from high school chemistry class.  It’s a pretty well-known one, but it’s worth retelling for anyone who hasn’t seen it before.  It’s also extremely easy to do at home (all you need is some salt and a 9-Volt battery), and if I can inspire a few people to perform a potentially dangerous experiment in their homes in the name of science, then I’ve done my job.

The theme of the experiment is getting hydrogen gas from water.  Before I first saw this experiment, I always thought of water as the world’s most stable compound.  It covers 70% of the earth and makes up 60% of the human body, and somehow in my mind that equated to it being perfectly “safe” and non-reactive.  But it turns out that splitting apart dihydrogen monoxide (water) is fairly simple.  All you need is a battery.

A battery is a fairly complicated thing.  But there is a simple way to think about it that generally guides you in the right direction.  I always imagine it as a pair of reservoirs: one containing positive charge and another containing negative charge.  Something like this:

These two “charge tanks” sit under the two terminals of the battery, and when the battery is connected to a circuit the negatives (electrons) flow from one tank to the other.  The voltage of the battery is a measure of how tightly-packed the charges are.  The closer the charges are to each other, the more strongly they will shoot out of their respective terminals when they are given a path to do so.  That’s why a battery’s voltage drops the more you use it: you are allowing the charge tanks to deplete, so that charges in a given tank don’t repel each other as strongly as they used to.  The lifetime of the battery is a measure of how big the tank is: it tells you how much current you can get out of the battery before it dies.  A 9V battery has a fairly high voltage (tightly-packed charges) but doesn’t last very long (the “tank” is small).  In contrast, one of those fat D battery has a low voltage (1.5 V) but can last a long time (it has a large tank).

So what happens if you put a battery in water?  Well, if you have pure water, not much.  The water molecule is electrically neutral, so it is not drawn to either terminal.  But if you mix some salt in the water, things are different.  Salt dissolves in water to leave behind positively-charged sodium ions and negatively-charged chlorine ions.  Once you put a battery in the water, the sodium ions migrate toward the “negative tank” and the chlorine ions migrate toward the “positive tank”.

At the positive tank, the chlorine ions get neutralized.  The chlorine ion has an extra electron, and this electron gets ripped off and pulled into the positive tank.  The resulting neutral chlorine atoms then bond together (since they are more stable together) to form , which is chlorine gas.  Chlorine gas is a serious poison, so be careful if you do this experiment at home.  Don’t do it on too large a scale (with your car battery or something), or it could be quite dangerous.

At the negative tank, something a little more complicated happens.  The electrons want to jump out of the tank, but they are more easily accepted by the water molecules than by the sodium ion (for some reason that is mysterious to me).  As a result, the electrons jump to water molecules, which then become unstable and split apart.   The result is that each water molecule is split into one (neutralized by the electron) and one .  Hydrogen atoms, like chlorine atoms, are more stable together, so two hydrogens get together and form gas.  The goes on to bond with the sodium left in the water or the iron on the battery leads (generally making the water dirty-looking).

The dramatic part, of course, is the hydrogen gas.  It bubbles quickly off the big lead of the battery, and you can collect it in a container if you do it carefully.  And since hydrogen is highly flammable, you can explode it.

I’m sure there are plenty of places on the internet where you can find better explanations of this experiment than I just gave.  Probably some of you reading this post could do better also.  But I highly encourage you to go out and have fun with this simple experiment.

Here is a video made by Mrs. G&L and I, so you can see for yourself.  The explosion at the end is pretty weak, but you’ll get the idea.

Morihei Uyeshiba (1883-1968) became a recognized master of aiki-jujutsu and several other arts. As he matured he became a strong proponent of nonaggression. In 1925, he organized a style of budo (”the way of the warrior”) to assist his own spiritual and physical development. The result was modern Aikido. The word Aikido is actually three Japanese words AI, KI, and DO that broadly translated means the “way” (DO) of “harmony” (AI) with the “forces of nature” (KI).

Aikido is not a conventional fighting art or sport. There are never competitions or tournaments, instead, it is a martial art, which develops the ability to harmonize with opposing forces rather than combat them. Because of this, many circular and spherical movements are involved in Aikido to redirect opposing forces towards a less harmful destination. In Aikido an attack is never stopped- it is redirected. Attacks are guided in a way that causes the attacker to be stopped by their own motion. In addition to throws, Aikido employs a number of locking and pinning techniques. Although these techniques can be painful and can quickly neutralize an aggressor, they are not designed to break bones or cause serious injury.

Aikido’s movements are natural ones that employ a keen understanding of body movement and physics theory. Since Aikido is not based on pitting strength against strength, it is practiced by men and women, children and older people.

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