One Large Sundial

On my way home from Yreka for my sister’s birthday, I stopped by the Sundial Bridge in Redding, CA. It is a very strange feeling seeing this gigantic foot bridge over the Sacramento river in the middle of little old Redding. Here are a few pictures:



The bridge was designed by Santiago Calatrava, who also designed the olympic stadium for the upcoming olympics in Rome. On the summer solstice, the bridge acts as a large sundial. I wonder if anthropologists 4000 years from now will wonder what we used this gigantic sundial for?
RuhRoh Update: Panos points out that the olympics are in Athens not Rome. God am I an idiot these days: what was I thinking? Also it is the roof of the stadium which is being designed by Calatrava, not the whole stadium. See the comment section for some pictures of the stadium.

Paper Collaboration Software

Recently, I completed a paper with Isaac Chuang and Aram Harrow. In the final stages of completing the paper we used a CVS (Concurrent Version System). For those not familiar with CVS, this is a piece of software which allows for version control (meaning it records the history of the source files) and nicely protects multiple authors working on the same source (basically this means multiple authors can work on the paper without fear of overwriting other’s changes.)
Using a CVS was definitely an improvement over the normal way paper collaboration works: the authors bounce emails back and forth with the source (aka LaTeX) attached. This essentially means that only one person at a time has “the token” and is responsible for working on the paper. While knowing that “you have the token” can press you into working efficiently to getting your changes done, not having anyone else working on the paper at the same time can be frustrating. Especially as a paper nears completion, and small changes are constantly being made by all authors, multitasking with CVS is definitely a plus.
But there are some issues with using a CVS which are more specific to scientific paper writing which make me think a paper collaboration CVS might be a really nice tool. Any ideas? Here is one idea:
Traditionally authors comment out sections which they change. Thus, for instance, if I am writing a new version of a paragraph, I will comment out the old version and keep it in the source. One reason for doing this is that it allows one to revert back fairly easily. With a CVS, of course, this is not strictly needed: the CVS is designed exactly to revert to prior version if necessary. But there is another reason why we comment out: we often cut and paste from the commented out component, or just want to quickly reread the commented out component as we write the new version. So the CVS needs some way of dealing with this technique: author’s want to have extremely easy access to previous versions. In fact what we really need is integration with an editor so I can turn on and off display of the “deleted” sections from prior version.

Schurly You're Joking Dr. Bacon

A new paper, a new paper! If you love the theory of the addition of angular momentum, and don’t we all just love the theory of the addition of angular momentum, then you will really love the new paper we (Isaac Chuang and Aram Harrow) just put on the arXiv. Unfortunately my spell check changed the title to Clench-Gordon and I didn’t notice. So I expect a lot of nasy emails complaining about the title. Doh. Well that’s what the replace button is for, I guess. Here is the paper:
quant-ph/0407082
Efficient Quantum Circuits for Schur and Clebsch-Gordon Transforms
Authors: Dave Bacon, Isaac Chuang, Aram Harrow
Comments: 4 pages, 3 figures

The Schur basis on n d-dimensional quantum systems is a generalization of the total angular momentum basis that is useful for exploiting symmetry under permutations or collective unitary rotations. We present efficient (size poly(n,d,log(1/epsilon)) for accuracy epsilon) quantum circuits for the Schur transform, which is the change of basis between the computational and the Schur bases. These circuits are based on efficient circuits for the Clebsch-Gordon transformation. We also present an efficient circuit for a limited version of the Schur transform in which one needs only to project onto different Schur subspaces. This second circuit is based on a generalization of phase estimation to any nonabelian finite group for which there exists a fast quantum Fourier transform.

Full-text: PostScript, PDF, or Other formats

Too Legit? Too Legit to Qubit?

Physical Review Letters has changed their sections around. Previously, quantum information was in the last section “Interdisciplinary Physics: Biological Physics, Quantum Information, etc.” For the more fundamental oriented papers, one would sometimes also submit to “General Physics.” Now quantum information has been moved to the new first section “General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.”
Is this a good thing? Since I am nothing if but a bag of poorly thought out opinions I will spew out some here. (1) It is nice to see that quantum information is consider a part of “General Physics.” “Interdisciplinary physics” seems a way to say, well there were these good physicists, and then they took interest in this other field which has overlap outside of physics, and since we liked these physicists we let them publish here. If I look at this move as acknowledging that quantum information has intrinsic value to physics, then I get goosebumps all over (sadly doubling the amount of stimulation I’ve had all day.) (2) The old “General Physics” section was notoriously harder to get papers accepted into if they had a quantum information tilt. Generally (err) this was because the papers submitted there were of a more foundational nature, and well, let’s not even go there. Will the movement of quantum information to general physics make it easier for foundational people to get published?

Stop! Right There at the Beginning!

There is no concept more evil, more corrupting than that of the continuum. Why at the very bottom of physics do we bury the most unprovable of assertions. All science is counting. No science counts for ever. Real numbers can never be more than conjecture.
But of course, you answer: it works so well! The conjecture has withstood ages, from Newton to Einstein to (fill in modern genius here.) Sure we can never prove the conjecture, but if it continues to serve us in building models of the world why should we get rid of it. Why, for that matter, should the dictates of science lead to dictates about physical reality?
The only crack we see in the idea of the continuum comes from quantum theory. Here, if the circumstances are right, we get discrete answers for different configurations. So, as many have suggested, when we try to construct a quantum theory of spacetime, perhaps there will be a discretization.
But even hear we come of short of ridding physics from the unprovable assertion. Even here we find, when we use the rules of quantum theory, that all probabilities are allowable. Again real numbers find themselves at the center of the theory.
Remarkably, there are ways in which one can get rid of both of these continuums (at least in a limited sense.) These are Roger Penrose’s spin networks. For sufficiently complicated spin networks, the networks posses two properties: they approximate directions and the approximate quantum probabilities. Combinatorial rules give rise to quantum probabilites and the full real span of probabilities is not postulated a priori. Combintaroial rules give rise to quantum probabilities which describe an object with with discrete degrees of freedom which approximate direction in three dimensional space. Funny but that they remain no more than a curiousity, or a way to find orthogonal sets of states in loop quantum gravity.
Real numbers. Bah. I’d rather believe in fairies. Us of the digital era, we are such pains in the rear.

On Top of Mt. Shasta

When I first caught sight of it (Mount Shasta) over the braided folds of the Sacramento Valley, I was fifty miles away and afoot, alone and weary. Yet all my blood turned to wine, and I have not been weary since. – John Muir, 1874

Unlike John Muir, I don’t recall the first time I saw Mt. Shasta. Having been born and raised in the nearby town of Yreka, the 14162 foot tall Cascade volcano has always been a part of my life. It was only after I left Yreka to attend college that I could return to Yreka and begin to appreciate the wine that flowed in Muir’s blood. It is hard to describe the majesty of Shasta: the way the volcano dominates the sky, the very different mountain presented to viewers from different perspectives, the white wonderland after a winter snow. Like most people spoiled with such beauty, it is easy to grow accustomed to the mountain. Easy to grow used to a unique gem.
My dad, Larry Bacon, climbed Shasta somewhere around ten times. Almost all of these climbs where before I was old enough to accompany him. I retain vague images of his climbs, shown to me on old slide-shows and told to me in humorous stories, but we never climbed the mountain together. A bad back, age, and time conspired, but this father’s day weekend, my dad and I finally made our joint ascent on the majestic Mt. Shasta.
My dad was full of strange little songs, whose origin, content, and tone were always of a quite questionable nature. The strange songs he would sing during his morning shower were a constant source of bemusement to all who had the luxury of hearing his rhapsody. One of the songs he liked to sing was a version of “On Top of Old Smokey”:

On top of Mt. Shasta
all covered with snow
we lost our hike master
to the rock piles below.

All blood and guts
he lay there below
our poor hike master
had stubbed his toe.

It was with this song, then, in the back of my head, that I stood in the parking lot of the trail-head Bunny Flats on the morning of Friday June 18, 2004, staring up a the dominating southwest side of Mt. Shasta:

The forest in this picture is clearly obscuring “the rock piles below” where, I could easily imagine, legions of hike master’s bones lay in their final resting places. To crack this mountain would require an elite team of experienced climbers ready for the challenge of a two day ascent. Mistaking the word inexperienced for the word experienced, however, our climbing group consisted of three first time climbers, myself and my two friends Luis de la Fuente and Patrick Hayden and a geologist, Luis’ dad Juan, whose last climb of Mt. Shasta occurred before all three of us newbies were born. Fresh blood be damned, there is nothing like the arrogance you can feel in your hiking skills just before a big climb. Here I translate this arrogance into my best Babe Ruth intimidation:

So, at about 11 a.m., we left Bunny Flats, loaded with gear to our day’s destination, Lake Helen. Our first rest came at Horse Camp, where we filled up our water bottles with “the cleanest water in the world” from the spring beside the Sierra club cabin. Here Luis rests under the shade of the cabin:

Luis, unfortunately had a cold equating to a fraction of his normal lung capacity and was therefore in much pain throughout much of our trip. Here we find this pain written into the creases on Luis’ face:

In the above photo, Patrick is hidden behind his hat and Juan is hidden behind Patrick.
The hike to Helen was quite fun with big packs on and medium soft snow. Here two lone hikers ascend away from the main path to the campsites at 50/50 flats:

After some trudging up some 3500 feet, which looked something like this

we finally arrived at Lake Helen, elevation 10400 feet.
Here are our two tents at Helen:

There is nothing much nicer than the feeling you get after setting up your tents. This is clearly why three quarters of Patrick and I have such big grins on our faces

Arriving early to Helen gave us plenty of time to stare up at the Red Banks, and wonder, where the heck is the rest of the mountain?

To bed at 8 p.m. for an early start of 4 a.m. the next day. Sadly I did not know that the tent I shared with Patrick had a window and that indeed this window was open during the night. I snuck in 4 hours of good hard sleep and then a lot of freezing off of my toes to rise at 3:45 a.m. After a bagel and some frozen Gatorade, we left camp at 4:30 a.m. There were about 10 headlights already proceeding up the hill below the Heart on Shasta, and as we left and looked back we counted around 30 more following us up the hill! Truly an amazing site all of these lights climbing up the mountain in front of you. Indeed the site must have inspired the still sick Luis who summoned some sort of superpowers from his quarter lung and made a massive push up to the chimney of the Red Banks. In the morning sun, Shasta casts a shadow onto the surrounding territory below, and, as you can see in this picture, even onto the morning haze on the horizon:

Here’s the view we had looking up at the Heart (the bare area in the middle of the picture)

Amazingly, given the sick Luis, we trudged up this part of the mountain and passed all of the people you can see in the picture in front of us.
So, up through the Red Banks we climbed. Sadly, I don’t have photos of the chimney we climbed in the Red Banks. When we finally reached the top of the Red Banks, we encountered our first taste of the famous Mt. Shasta winds. Just below Misery Hill, we stopped to take off our crampons and were blasted by some nice cold hard winds.
We all sort of climbed up Misery Hill at our own pace. This was a part of the hike where I could just trudge along at a slow steady pace up the cold windy slope. I felt very alone and my thoughts drifted to thinking about my dad. How many times had he been up through this same misery? What was he thinking when he made this slow solitary climb to a reward, the peak, totally hidden from view? The reward was the climb, the beauty of everything around you, a small dot on a big hill. About half way up Misery Hill I found that if I climbed over to the right, off of the bare hill and onto the snow, the climbing was much easier and there was little to no wind. Always be on the lookout for ways to turn misery into a serene climb.
At the top of Misery Hill, we got our first good view of the true summit of Shasta, a spectacular looking final hill with a few little dots, hikers, dwarfed by the final summit

Hiho, Hi ho, it’s off to the summit we go:

Finally, the top! At 8:45 a.m. we reached the summit of Shasta. The weather was absolutely fantastic: very little wind and quite pleasantly warm. Amazing! The views, to say the least, were astounding. Here at 14162 feet, Luis signs the log book:

The final summit of Shasta has three high levels, the highest being on the south east of the summit. Yreka is to the north of Shasta and so we climbed over to the north west peak in order to spread my dad’s ashes.
So, there I found myself, standing on top of Mt. Shasta, looking north across the Shasta Valley to Yreka. We didn’t perform any ceremony, so to speak: pomp and circumstance were the last things my dad would give a hoot about. I had carried a portion of my dad’s ashes in a neon blue cylinder. Of course the damn thing was crazy hard to open, but I finally twisted the top off. The wind picked up a bit blowing to the south east. Thus I was able to throw my dad off the edge of Shasta, toward Yreka, such that he would splatter all over the rock’s facing Yreka. Of course this meant I got some of my dad blown in my face and stuck in my teeth. And here lies Larry Bacon (1940-2004):





As one might expect, many of the local Native Americans regard Mount Shasta as a sacred mountain. In fact, one of their legends is that the world was created from the summit of Shasta downward. Shasta was so special to these tribes that climbing above tree level was strictly prohibited. The only reason one could climb above tree level, according to this custom, was if you were called to the mountain to die. I like to think that the mountain called my father to die. It’s just that the mountain called him nearly forty years ago, when my dad visited Yreka looking for a job. Called to the mountain, he found his paradise: the beauty of Siskiyou county, the community of Yreka, his family, wine, dogs, gardening, cooking, history, the stars, and everywhere a sense of humor and amusement at the surrounding world. All of this, the mountain gave to my dad. And to the mountain, now, my dad has given a small part of himself. Indeed, if Shasta were to explode today, bits of my dad would fly out directly toward Yreka, where so much that he loved, lived and lives.
A quick photo with Patrick and Luis

and with Luis and Juan

and then on down the mountain we went. At this point the summit was getting to be more crowded and on the way down we were quite jubilant. Here Luis and Patrick mock the other climbers who were struggling to the top by pretending to be stuck in super strong Shasta winds:

Not too nice, fellas!
Here is Patrick contemplating the top of Whitney glacier

and a nice picture of Shasta’s smaller twin, Shastina

The best thing about coming down a mountain like Shasta is glissading. Here Luis demonstrates dubious form:

Patrick attempted to glissade through the chimney at the Red Banks. By attempted, I mean, he gain a ton of speed, attempted to dig his ice ax into the snow, lost his ax, went flying down the chute, before self-arresting on the side of the channel. Sadly I was too busy yelling at him to take pictures of this fantastic feat. But here is Patrick contemplating whether to attempt this foolish act or not:

Here my butt gets really really wet:

Well, that’s the story of how my dad went to the top of Mt. Shasta one last time. So if you’re ever driving on I-5 past Shasta, I hope you look up at the mountain and wave hi to my dad. He’ll be looking down at you, and laughing his ash off.

Beam Me Up Ion Traps

As will be spreading through the mainstream news shortly, I’m sure, Nature has two papers out today demonstrating the teleportation of the internal states of trapped ions. Both the NIST and Innsbruck groups have, using fairly different ion trap systems, succeeded in deterministic teleportation of the internal states of the ions. Woot! Woot! Not only are both of these experiements gorgeous, they are sure the sign of much more interesting protocols to be implemented in the near furuture (or, well, the experimentalist’s version of the near furture.) This is the first demonstration of deterministic teleportation of massive qubit systems (there has been a continuous quantum variable deterministic teleportation experiment done using light.)
A few stats.
Ions
NIST: 9Be+
Innsbruck: 40Ca+
Fidelitity
NIST: 76% to 80%
Innsbruck: 73% to 76%
Distance teleported
NIST: 100s of micrometers (?)
Innsbruck: 10 micrometers
Qubit teleported
NIST: Hyperfine ground states: F=1,m=-1 and F=2,m=-2
Innsbruck: ground state S_1/2 (m_J=-1/2) and metastable state D_5/2(m_J=-1/2)
The main difference between these two experiments is in how they achieve individual addressing. The NIST group has these really neat traps which allow you to move the ions into different sets of trapped ions and then address them spatially. The Innsbruck group uses some neat tricks that allow the internal states to guide which qubits they are coupling their laser light to.
It’s experiments like these that make me even more of an optimist about quantum computing (are we all supposed to use the work reaganist instead of optimist now?) Sure we’ve seen teleportation before. But, especially in the NIST experiment, not in such a way that it is clear that it is just the beginning of a long line of rockin bigger and better experiments (ion traps rock, man!)

Occam

I put away Jorge Luis Borges many years ago when I wrote my Literature thesis as an undergrad. Tonight I returned to him and read Death and the Compass:

“It’s possible, but not interesting,” Lönnrot answered. “You will reply that reality hasn’t the slightest need to be of interest. And I’ll answer you that reality may avoid the obligation to be interesting, but that hypothesis may not . . .”

Why Your Self Image Matters

Without a sense of your place in the universe, you end up writing funny shit:

The Revolution Against Evolution, http://www.rae.org is not associated with the Raelians http://www.rael.org. The Raelians claim to be creationists, but not in the Biblical sense. Instead they believe that life was imported from outer space by aliens. Their god is a UFO driver. Our group, Revolution Against Evolution, is made up of traditional Biblical Christians who believe in a supernatural creator God, and his son Jesus Christ. We in no way believe that this Christ was a space alien. We do suspect, however, that the god the Raelians serve and believe in is a counterfeit, either of their own imagination, or demonic in nature. Our creator God of the Bible is not a super-technological god; He is a supernatural God.