Wednesday, February 8, 2017

Gaussian Beam-Propagation Theory for Nonlinear Optics - Featuring an Exact Treatment of Orbital Angular Momentum Transfer

Gaussian Beam-Propagation Theory for Nonlinear Optics — Featuring an Exact Treatment of Orbital Angular Momentum Transfer

We present a general, Gaussian spatial mode propagation formalism for describing the generation of higher order multi-spatial-mode beams generated during nonlinear interactions. Furthermore, to implement the theory, we simulate optical angular momentum transfer interactions, and show how one can optimize the interaction to reduce the undesired modes. Past theoretical treatments of this problem have often been phenomenological, at best. Here we present an exact solution for the single-pass no-cavity regime, in which the the nonlinear interaction is not overly strong. We apply our theory to two experiments, with very good agreement, and give examples of several more configurations, easily tested in the laboratory.
Subjects: Optics (physics.optics)
Cite as: arXiv:1702.01095 [physics.optics]

Friday, February 3, 2017

The Future Quantum Internet Will Have “Made In China” Stamped All Over It!

From 2006 through 2010, I participated on a large, $1.5-million-a-year Quantum Computing Concept Maturation (QCCM) in optical quantum computing that was funded by the Intelligence Advanced Research Projects Activity (IARPA), which was formerly known as the Disruptive Technology Office, which was formerly known as the Advanced Research and Development Activity (ARDA), which was formerly known as the NSA, which were all funding agencies for the US intelligence community. The changes in names, acronyms, and, more importantly, the logos took place at a frightening pace that made it hard for the research scientists to keep up. I personally had funding for optical quantum computing from 2000 to 2010, which came under the umbrella of each of these agencies in sequence and there were even two separate logos for IARPA in use at the same time. When the acronym IARPA showed up in 2007, all my colleagues would ask me, what the heck is IARPA? To this I would respond, it is the Defense Advanced Research Projects Agency (DARPA) for spies (see Figure 4.9).
But in any case, the photonic QCCM, led by American physicist Paul Kwiat, had collaborators that stretched from Austria (Anton Zeilinger) to Australia (physicist Andrew White). We had what we all thought were great results; we submitted in 2010 an essentially renewal proposal and we were not funded and neither was anybody else in photonic quantum computing.
In the case of photonic qubits, this dropping of optical quantum computing by IARPA was a bit hasty in my opinion. While the photonic quantum computer may be a bit of a long shot for the scalable quantum computer, all hardware platforms are a long shot, and photonics is the only technology that would allow us to build the scalable quantum Internet. There is a good analogy. In the 1970s and 1980s, there were predictions that silicon chip technology was coming to an end, and there was a great DoD-funded push to develop scalable classical optical computers. The thought was that as we put more and more circuits closer and closer together on the silicon chips, the electromagnetic cross talk between the wires and the transistors would grow without bound limiting the  number of processors on a chip. What was not foreseen was the development of good integrated circuit design rules, developed by American computer scientists Caver Mead, Lynn Conway, and others, which showed that the cross talk could be completely eliminated. But until that was understood, the funding for the competing optical computing rose and ran for a while and then collapsed in the mid-1980s when it became clear that the Intel silicon chips were not going anywhere and that predictions of their demise were overrated. The optical classical computer program was viewed as a colossal failure and to say you were working on optical classical computing became the kiss of death. But it was not a failure at all. The optical switches and transistors developed for the scalable optical classical computer found their way into the switches and routers and hubs for the fiber-optic-based classical Internet. The future quantum Internet will also require the manipulations of photons at the quantum level—a quantum repeater is a device for transmitting quantum information over long distances. The quantum repeater is a small, special-purpose, optical, quantum computer that executes a particular error correction protocol. The future of the quantum Internet is in photons and the short circuiting of the development of optical quantum information processors in the United States means that the future quantum Internet will have “Made in China” stamped all over it.

Figure 4.9: A composite study of the logos of ARDA throughout the ages. From 2000 to 2010, I had continuous funding for research in quantum information processing, which as far as I could tell came from one place, but for which I had to change logos five times, starting with the NSA logo on the left (2000) and ending with the second IARPA logo on the right (2010). The penultimate IARPA logo on the right had a life span of only 2 weeks and you can see that it is the logo for the Director of Central Intelligence with the letters IARPA badly and hastily photoshopped across it. In the background is a spoof of a composite map of the lands of Arda from the fictional works of J.R.R. Tolkien. (The sea monster and sailing ship are taken from ancient manuscripts and no longer subject to copyright. The map is based on “A Map of Middle Earth and the Undying Lands: A Composite Study of the Lands of ARDA,” author unknown. (Explanation of the jokes: The Unlying Lands should be the Undying Lands in Tolkien’s works. Nimanrø should be Numenor, Mittledöd should be Middle Earth, Odinaiä is Ekkaia, and Darpagar is Belegaer. ODNI is the Office of the Director of National Intelligence, NIMA is the National Imaging and Mapping Agency [now the National Geospatial-Intelligence Agency], NRO is the National Reconnaissance Office, DARPA is the Defense Advanced Research Projects Agency [parts of which were carved out into ARDA], and DoD is the Department of Defense.)

This post is directly quoted from my book, Jonathan P. Dowling, Schrödinger's Killer App — Race to Build the World's First Quantum Computer (Taylor & Francis, 2013) pp. 171–173.

Thursday, January 19, 2017

Statement of Teaching Philosophy

From the — I actually wrote this!? — file....

Statement of Teaching Philosophy
Jonathan P. Dowling

As the physicist and famed textbook author John D. Jackson once said, “Asking an experienced teacher about his teaching philosophy is like asking a fish about his swimming philosophy — it had better be second nature!” Another quote I am fond of was from one of my own woman undergraduate students, who told me, “The reason you are such a great teacher, is that there is no concept too easy for you to explain!” This taught me a lot. Anybody at my level can explain the difficult concepts — that is the easy part. Apparently my gift is to have the patience and wisdom to take a concept that may seem “easy” to me and parse it in a way that it resonates with each student.

At the graduate level, I view my role as instructor to be far more than a lecturing and grading automaton, but rather a role model for the graduate students to emulate to be the teacher and physicist. As a student, I was able to learn how to teach by emulating the masters, and learn how not to teach by studying pitfalls. Physics is a notoriously difficult subject to teach well, as the subject matter has a tendency to delivered in a dry, stuffy atmosphere, where any creative embellishments in the delivery of the material are viewed as a distraction from the accurate conveyance of the subject matter.

In order to make the subject matter of physics come alive, I have taken it upon myself to read many biographies and histories of famous physicists and their discoveries, and I weave these stories into my presentations in such a way that the spirit of Einstein and Schrödinger may live again in the room, as we learn together about not only their successes, but also their failures. Too often, physics is presented as a fait accompli, which sprang complete from the foreheads of our forefathers in its present, canned, homogenized, and pasteurized form Young scientists, struggling with their own successes and failures in their own research, need to know it is okay to make mistakes. This lesson is one of the most important for a student to learn. The second most important point is to have fun in what you are doing and to love it. It is hard for some young people to believe that physics should be fun, so I try bring them around by having fun with it myself in the classroom. With that they learn also that life is too short not to do what they love most.

Once you get across the point that learning physics can be fun, and that it is fine to make mistakes, then the students are all on board and it is smooth sailing. The quiet ones open up. The bold ones become wise and thoughtful. The assignments seem less tedious, the exams less onerous. For required core graduate courses, such as quantum mechanics, this lesson needs to be learned to face the vast amount of required material and the grueling exams. For graduate electives, such as the two-semester quantum optics course I designed and executed, it is critical to get this out front so the students will find time in their busy schedules to work hard with me on a mere elective.

From an operational point of view, I mix up the traditional lecture format with either planned or unplanned in-class student presentations. One of my favorite modes of classroom instruction is to take a seat among the students and discuss with them, not lecture to them, with each taking a turn to lead the discussion or go to the board and make their point, in mathematics or prose, and to have their peers and me weigh in on that point. Once broken of the fear to speak up in class — learning begins. This goes for my formal classes, and for my own research group meetings and seminars — where even the youngest undergraduate student must be made to feel free to be able to challenge a point the professor is making — especially since the undergraduate student is often right! A recent visitor to our group, Prof. Hal Metcalf from the State University of New York, was enthusiastic about our group discussions because, unlike in other research groups he’s visited, everybody in my group has a voice — and more importantly — is not afraid to use it!

In the end, as I teach, I am myself a role model for the student, not just as an aspiring physicist and scientist, but as a member of the educated citizenry that will guide the future of our world.

Sunday, June 5, 2016

Wheeler vs. Dowling in the War of the Commas

In 1990, while still a postdoc at the Max Planck Institute for Quantum Optics in Garching, I was writing a paper with the John A. Wheeler and the Wolfgang P. Schleich, entitled, “Interference in Phase Space.” I had first met Wheeler years before, when I was an undergraduate student at the University of Texas, where I audited his course, “Quantum Measurement Theory,” taught jointly with Wojciech H. Zurek. When I asked Wheeler for permission to audit, he said to me, “How much trouble could one undergraduate student be?” 

Taking that as challenge, I would sit in the front and constantly ask questions until the graduate students threatened to take me out in the parking lot and beat me up. I finally told them all that I knew karate (at that time a yellow belt in tae kwon do) and they left me alone after that so I could still interrupt class.

The paper, “Interference in Phase Space,” was a review article on phase-space methods in quantum optics; a topic that Wheeler and Schleich began working on in Texas when Schleich was a postdoc there. My primary job on the paper was to type up the whole thing in TeX. (This was back in the day when women were women and men were men and we all wrote our own macro packages and had no need for that namby pamby LaTex.) I also helped with some of the calculations and preparing the figures. Even sometimes I had help with double-checking the English, as when Schleich accidentally translated the German nickname for Bohr’s Correspondence Principle, Bohr’s Zauberstab, as “Bohr’s Magic Stick” (instead of “Bohr’s Magic Wand”).

Wheeler refused to let anybody start writing the body of the paper until we had all the figures and figure captions done up to his liking. We would lay the figures end to end and endlessly discuss their ordering, the captions, the style of the drawings, etc. In this way we had a very clear storyboard of the paper long before I started typing the main text. This is a very useful technique that I still use to this day, especially with students and colleagues who have writer’s block.

Schleich and I were working in Garching, Germany, and Wheeler was back at Princeton. As I typeset the manuscript, which eventually ran to nearly 50 pages, I would fax drafts of it to Wheeler to mark up and fax back to me to make his changes. We must have had done nearly 20 rounds of this faxing back and forth. Of course, being the junior author, I mostly implemented Wheeler’s changes as were given to me, but for one particular typesetting bone of contention. When Wheeler would refer to a short snippet of mathematics (that followed the noun that defined it) let us say “The variable x is inserted into the function f(x) in order to....,” he would put these math terms in parenthetical commas, e.g., “The variable, x, is inserted into the function, f(x), in order to….”

If you have read Knuth’s big book of TeX or various physics author style manuals, you learn that putting short math expressions like this in commas is considered old fashioned and is frowned upon. Figuring that the Editors would delete these commas in the final typesetting at the Annalen der Physik, I simply left them out of the manuscript. 

In that way then the battle with Wheeler over the commas had begun.

I would diligently fax the 50-page draft of the manuscript to Princeton, over and over again, sans the parenthetical commas around the short math, and Wheeler would send back his revised draft where, by hand, he would painstakingly add each and every one of those mission commas back in again. One must realize in a 50-page theoretical physics paper there were thousands of such corrections in each round. Just writing the commas in, alone, must have taken him hours in each review.

Finally he had enough. One day my office phone in Germany rang and it was Wheeler, calling long distance from Princeton, and he was understandably quite upset. “Dowling, he growled into the phone, why are you not putting my commas back into the manuscript!?” I replied, evenly, “Prof. Wheeler, putting parenthetical commas around such short math expressions in a physics journal is old fashioned and is recommended against in the journal’s style guide. Besides, the editors will just remove them.”

Stunned into a moment of silence, Wheeler then barked back, “I have been putting parenthetical commas around my short mathematical expressions since before you were born!” I paused, and then answered, firmly, “Perhaps so, Prof. Wheeler, but it is I who is typing this darn 50-page manuscript!”

He hung up on me.

I won the battle. In the end the commas stayed out. (I don’t think Schleich ever knew about this battle.) Some years later, in the mid-1990s, I ran into Wheeler at a conference reception. I went to say hello but at first he did not recognize me. So I said, “Wheeler, it’s me, Dowling — the smart-mouthed postdoc who would never put your commas back in our manuscript!” Wheeler’s jaw dropped and then, just when I though he was going to punch me, he started to laugh, and then he patted me on the back. “Dowling! You know you know that fight over the commas nearly put me in a coma?” Then I laughed too and wandered off to the bar.

That was the last time I ever saw Wheeler.

Sunday, January 3, 2016

Quantum Pundit's Science Predictions for 2016!

"Prediction is very difficult, especially about the future." 

Niels Bohr


At the end of each year, multitudes of science rags (on and offline) present their lists of the N (where N is around 10) most important science discoveries of that year. For 2015, a quick and unscientific Google search provides the following top-ten-list fodder for that year in review:

1.     Researchers Discover New Phase of Carbon
2.     Astronomers Discover ‘Fat Jupiter’ And ‘Twin Earths’
3.     Doctors Grow Human Vocal Cords from Scratch
4.     Have Scientists Found A New Particle Bigger Than Higgs Boson?
5.     2015 is Hottest Year on Record
6.     New Pluto Photos Show Edges of Its Frozen Heart
7.     Europe To Build Base On MOON By 2030 Using 3D Printer
8.     China Set To Launch 'Hack Proof' Quantum Communications Network
9.     Spooky Action at a Distance Is Real
10. Neil deGrasse Tyson Claims Entanglement can be used to Communicate Backwards in Time

But highlighting what happened in the past year is easy. The real money is predicting what will happen in the year to come. Here are some actual psychic predictions for 2016 from true psychics (as opposed to all those fake ones):

1.     Scientists Will Breed a Hybrid of a Dog and a Cat
2.     Drones Will Strike Buckingham Palace
3.     Naked Picture of Kim Jong-Un Will Cause a Political Row
4.     World Peace Will Break Out
5.     Australia Will Soon Be At War
6.     Farmers Will Develop a New Strain of Cauliflower
7.     Justin Bieber will Become Involved With an Older Woman
8.     A Comet Will Come Out of Nowhere and Bring Awe and Wonder to Humanity

It would appear that Niels Bohr was wrong; predictions about the future are remarkably easy to make — so long as they don’t have to be also true. And so month-by-month here are my psychic science predictions for 2016.  

(Disclaimer: Quantum Pundit's psychic predictions have no basis in science and are provided here for entertainment purposes only.)

January — High Energy Physics


CERN announces that the Large Hadron Collider (LHC) has found evidence for yet a third Higg’s-like resonance at a whopping 1,125 GeV. In the ecstasy of irrational (and un-peer-reviewed) exuberance, CERN leaks information about the discovery to the Journal of Irreproducible Results, the National Enquirer, and Portable Restroom Operator Monthly Magazine. Sole evidence for the new particle, dubbed by CERN as the “triphoton”, is what appears to be a tiny bump, nearly imperceptible to the human eye, on a single data curve displayed on a low-resolution CRT computer screen in the LHC cafeteria (between the toilets and the ATM). Nevertheless, the story is picked up by the Associated Press, who renames the triphoton “The Holy Ghost Particle” — third in a row after, "The God Particle (the Higgs Boson) and "The Jesus Particle" (the diphoton). Within several days thousands of theory papers are posted to the HEP-TH high-energy theory preprint archive explaining the physical origins of the triphoton. (However, no two of any of these thousands of theory papers agree with each other.)

Within hours of the announcement, the Facebook posts and Twitter feeds of scientists the world over are bogged down with requests for input from sketchy online newspapers, and the Huffington Post, about their opinions on the existence of the triphoton, and particularly, whether or not they believe that its discovery indeed provides proof for the existence of The Holy Trinity. Several hundred physicists claim that they do indeed believe precisely this, in a shameless bid to win the 2016 Templeton Prize. Pope Francis refuses to comment on the data, saying only, "Who am I to fudge?"

A Twitter flame war over the Holy-Trinity-particle question breaks out between Richard Dawkins, the Archbishop of Canterbury, and Koko the Gorilla, which causes the entire Internet to crash for a nearly a minute around midnight on January 5th, the feast day of St. John Neumann. Upon seeing this happen, unbelieving quantum physicists the world over undergo a spontaneous conversion to the Holy Trinity Particle creed. (The next day, however, most of them renounce their newfound belief when Pope Francis explains to them that St. John Neumann and St. John von Neumann were two entirely different people.)

As more and more data is collected, the data bump never seems to be any clearer, and stubbornly stays within only a single sigma of statistical confidence level. Finally, on January 31st, the feast day of St. Xavier Bianchi, a member of the LHC janitorial staff points out that the so-called bump is actually a fingerprint smudge on the computer screen, and he promptly removes it with a spritz of Windex and a Wet Wipe. This explanation for the data bump causes great dismay for the loop-quantum-gravity theorists, until the same janitor explains to them that St. Bianchi is not the patron saint of the Bianchi identities.

Later in the year, stand-up comedian, rabbinical scholar, and string theorist, Sarah Silverman, will publish a paper in which she claims to have found hidden messages in the Pentateuch that predicted the existence of the pentaquark nearly three thousand years ago. Dr. Silverman handily wins the 2016 Templeton Prize, only to announce on her deathbed (many years later and after she spent all the money) that it was all a hoax and that she never believed in pentaquarks in the first place. With this off her mind she dies peacefully, surrounded by friends, family, and the ghost of Murray Gell-Mann, who then guides her through the eight-fold way into the afterlife.

February – Biochemistry


The agrochemical giant, Santmono Corporation, modifies the gene-editing tool, CRISPR/Cas into a now trademarked tool they rename TOASTR/Aas. The TOASTR/Aas gene-splicing tool is specifically designed to make any photosynthetic plant life more susceptible to being killed off by Santmono’s premier weed killer, Roundoff. The TOASTR/Aas tool is used to make a gene drive that is then "accidentally" released into the wild, causing the collapse of worldwide agriculture. Santmono responds by marketing a “non-plant-based-human-food supplement” they christen SoLessGreen™ in order to prevent worldwide starvation. Santmono gives sole distribution rights to distribute SoLessGreen™ to the now nearly bankrupt Pichotle restaurant chain (whose motto “Food With Decency!” had recently been changed to “Food with Dysentery!”). Pichotle is relieved, as, unlike their previous food line, it was clear that no virus, bacterium, or prion could survive for more than a few seconds in SoLessGreen™. The truth about the origins of SoLessGreen™ is uncovered by a group of agri-terrorist grammarians but the secret is never revealed to the public, as the group cannot agree if the public announcement should read “SoLessGreen™ is people!” or “SoLessGreen™ are people!” and Charlton Heston is no longer around for a consult.

March – Biology


Urban biologists will report that "pizza rat" (the rat caught on film dragging a slice of pizza into a New York subway station), is not an ordinary Norwegian rat but rather a newly evolved species of rat that is building a large hive-like structure (complete with a three-ton queen rat) in the New York subway tunnel system. The new species is named Rattus pizzapylori, and it is discovered that it can only survive by eating New-York-style pizza (much as a panda can only survive by eating one species of bamboo). As the hive grows to the point where geysers of engorged rats are spouting forth from all the street manholes (which is, frankly, just a regular day in New York City), Mayor Bill de Blasio concocts a plan to feed the queen rat a Chicago-style pizza, which is well known to be inedible by all life forms. The queen dies within minutes, taking the entire hive with her, and as torrential rains from a freak typhoon called “Super Storm Shandy” wash the carcasses of dead rats from the sewers out into Long Island Sound, not one of the New Yorkers notices a damn thing.

April — Space Science


NASA scientists excitedly hold two last-minute press conferences where they announce that they have found water on Mars and that the Voyager spaceship has left the Solar System. When a canny reporter for the New York Times retorts that these same NASA scientists have been making these exact same two claims every few months for the past ten years, the reporter is taken to JPL and given a deep-space probe.

After NASA's New Horizons mission captured a spectacular photo of a human-heart-shaped feature on the surface of Pluto in 2015, in 2016 it will fly by one of Pluto's orbital companions and capture a photo of a new feature on its surface that looks like a pair of human buttocks. Scientists extol the fact that Charon had been literally mooning Pluto for millions of years. The International Astronomical Union (IAU) passes a resolution to rename Pluto the Dwarf Planet, "Sneezy".

SETI will announce they have discovered evidence than extraterrestrials have been secretly communicating with Earth for several decades. They triangulate the signals and find that they have all along been directed to Donald Trump’s hair. Further investigations reveal that his hair is actually a orange-hamster-like alien life form that has been glommed onto his noggin since the 1980s and stealthily controlling his mind using telepathy, in order to win the US presidency, and thus hasten the hostile takeover of the Earth by a sentient race of orange hamsters. Scientists immediately embrace the news, as it is clear that no other theory can reasonably explain the success of Trump’s television show, The Celebrity Apprentice. CIA operatives work feverishly to create a portable psionic-dampening field around The Donald’s hair, and catastrophe is then narrowly averted. SETI scientists will have no time to relax, as further analysis of the extraterrestrial signals reveals the existence of a second invasive alien species. One of which, disguised as a white feather duster, is attached to the otherwise bald head of Bernie Sanders.

May — Technology


The 3N Corporation will develop a 3D printer that is capable of printing working copies of itself using only solar energy and sand as input. A shipping error results in a prototype of the printer being shipped to a FedEx (formerly Kinkos) copying center in Barstow, California. The store manager, unwilling to pay the return-shipping fee, dumps the 3N3D printer in the local landfill, where it springs into action and begins churning out copies of itself at an exponential rate. Within days the entire Inland Empire is blanketed with 3D printers that threatened to end life on Earth, as we know it, by converting the entire planet’s crust into 3D printers. In the nick of time a fleet of stealth bombers from nearby Edwards Air Force Base, equipped with top-secret laser cannons, blankets the region with laser fire, thereby melting all the printers (and the inhabitants) into a molten sea of glassy slag. A memorial plaque is placed in what was once Barstow to honor all of those who were vaporized.

Nearby, Gögle Corporation will launch its well-publicized “Project Loonacy” from Moffett Federal Airfield near Mountain View, California. As originally envisioned, fleets of high-altitude helium filled balloons, carrying on-board solar-powered wireless routers, would provide Internet access to the most inaccessible spots on the globe. Alas, due to the continuing worldwide helium shortage, Gögle takes the drastic measure of replacing the helium-filled balloons with hydrogen-filled balloons instead. A memorial plaque is placed in was once Mountain View to honor all of those who were vaporized.

Waysag Corporation will release a new model of their hoverboard that will actually hover (as opposed to just roll around on the sidewalk an periodically pitch the rider into oncoming freeway traffic). They solve the ongoing problems related to the devices’ batteries bursting into flames — or just flat-out exploding — by replacing all the rechargeable sealed lead acid batteries with plutonium fuel cells. This works well until a group of hoverboard enthusiasts, returning from a hoverboard competition in Duluth, Minnesota, decide to pack several hundred of their hoverboards into a single towed U-Haul trailer. They exceed critical mass for runaway nuclear fission and Duluth is reduced to a smoldering pile of glowing embers, while the rest of Minnesota enjoys an early summer. A memorial plaque is placed in what was once Duluth to honor all of those who were vaporized.

June — Mathematics


After the famous 2002 proof that PRIMES is in P, and the recent tantalizing 2015 result that the Graph Isomorphism Problem is solvable classically in quasi-polynomial time, a Lithuanian mathematician at the University of Vilnius, discovers a classical polynomial time integer factoring algorithm and programs it into a desktop telephone-answering machine before he is assassinated by a gang of rouge computer scientists. The discovery renders the most pressing cryptoanalytical need to develop a quantum computer moot, and the computer scientists hold the economy of the World hostage by threatening to publish the classical factoring algorithm on the Internet, thereby causing collapse of Internet commerce. Robert Redford and his group of hackers (secretly working for the NSA) take out the rouge computer scientists, and the telephone answering machine is recovered and secreted in a giant underground government storage facility, next to the Arc of the Covenant. In order to keep all this a secret, the NSA gives Dan Akroyd a Winnebago as a bribe to maintain his silence.

July — Computer Science


Not to be outdone by the success of IBM's Watson computer in playing Jeopardy, T-Wave Systems programs its newly released T-Wave 3Y Computer System to play Wheel of Fortune. In a double-blind series of tests, the T-Wave machine scores slightly better than chance, when pitted against either Richard Dawkins, The Archbishop of Canterbury, or Koko the Gorilla. T-Wave trumpets this result as proof of the existence of an exponential speed-up in their quantum computer. However MIT professor Aaron Scottson, ever the party pooper, points out that the T-Wave machine cheats as it is also programmed to regularly compliment Vanna White on her snazzy outfits, and given that it is she who is in charge of choosing which letters on the board to light up, it is Prof. Scottson's claim that T-Wave is skewing with the results.

August — Astronomy


The Kepler, space-based, exoplanet observatory loses the third of four original gyroscopes, potentially rendering the craft useless, as it is now unable to point itself. After losing the second of four gyroscopes in 2013, crafty NASA engineers were able to stabilize the craft by balancing the solar wind pressure across the surface of the spaceship. With the third gyroscope now out of commission, the engineers will come up with a fix whereby, in addition to the solar wind, they balance the cosmic background radiation and vacuum fluctuation pressure across the ship. This leaves the telescope pointing forever at a single fixed point in the sky. There the astronomers find, orbiting a Sun-like star in the Goldilocks zone, an Earth-sized planet that appears to have liquid water and the spectrum of oxygen in the atmosphere; both telltale signs of life. They name the planet Kepler-137q but the press quickly nicknames it “Alderaan” given its likeness to the fictional planet from the Star Wars films. The planet also has orbiting it what appears to be a small moon, which the astronomers name “Lovell” (after retired astronaut Jim Lovell).

After several weeks of observing Alderaan and its companion, one NASA astronomer exclaims, “That’s no moon!” and Alderaan suddenly disappears in what appears to be catastrophic explosion. Meanwhile the so-called moon, Lovell, moves out of view, seemingly under its own power. Given that they literally have nowhere else to look, the sad and lonely NASA “extronomers” continue to look for Lovell in Alderaan places.

As August comes to an end, a comet will appear out of nowhere and bring awe and wonder to humanity.

September — Economics


At the headquarters of the investment management company, Pimpco Corporation, in Oldport Beach, California, Satan Incarnate will appear in the cubicle of a “quant” stock market trader, named Donna Giovanni, who is located in a windowless subbasement of a Quonset hut on the perimeter of the Pimpco campus. Lucifer will offer Ms. Giovanni a working quantum computer, a faster-than-light communicator, and a quantum algorithm for solving the Black-Scholes stock derivative equation in BQP runtime. All this he offers her in exchange for her immortal soul. Ms. Giovanni, who is sure she is already damned anyway for working at Pimpco, gladly accepts the offer. She then sets up a superfast trading station in the sub-basement that allows her to make stock trades faster than anybody else, by exploiting the quantum algorithm, the quantum computer, and by communicating with the Wall Street trading computers instantaneously, using the faster-than-light communicator. Within a few weeks she earns trillions of dollars for Pimpco (and a hefty billion-dollar bonus for herself) before her shenanigans trigger a stock market flash-crash that wipes out the life savings of millions of people and sends world into a second great recession. Luckily for her, Ms. Giovanni cashes in her stocks before the crash, is promoted to president of the company, and lives a long and luxurious life off her wealth before she dies peacefully in her bed surrounded by her friends, family, Beelzebub, and the ghost of Murray Gell-Mann. As Gell-Mann guides her through the eight-fold way into the afterlife, the Devil returns empty handed to Hades. (As Ms. Giovanni had suspected, she had already sold her immortal soul to Pimpco many years before Old Scratch* ever showed up.)

* “Old Scratch” is a name of the Devil, chiefly in Southern US English. It is rarely, if ever, used to refer to Prof. Murray Gell-Mann.

October — Quantum Physics


Neil deGrasse Tyson, still reeling from the repercussions of claiming in 2015, on his television show StarTalk, that backward in time communications are possible using quantum entangled particles, contacts Ms. Giovanni at Pimpco corporation (after the stock market crash) and offers to buy her diabolical faster-than-light communicator for a bargain price. (A faster-than-light communicator doubles as a backwards-in-time communicator.) Dr. deGrasse Tyson then uses the machine to send a message backwards in time to tell his earlier 2015 self not to make that claim on television again, until such time as the future Dr. deGrasse Tyson had secured the patent rights to the communicator. The plan backfires when, due to quantum coherence, the message has the effect of producing a quantum-Schrödinger-cat-like superposition of Neil deGrasse Tysons, one who did make such a claim in 2015 on television and the other who did not. These deGrasse Tysons become quantum entangled with a superposition of future 2016 deGrasse Tysons, one who patents the faster-than-light communicator and the other who does not.

The resulting paradox rips a rift in the entire space-time continuum, which threatens to suck the entire universe into a super-duper massive black hole whose center is located at the Tokyo patent office. The universe is saved, however, at the last minute when a strange looking Englishman, wearing a bad suit, a bowtie, and a fez, emerges from a blue police box in the lobby of the Hayden Planetarium and repairs the rift (and also undoes the stock market crash and the collapse of worldwide agriculture while he is at it) with a glowing and buzzing green handheld magic wand, which the curious traveller claims is a screwdriver. After this all blows over, quantum physicists decide to hold an emergency international workshop on closed time-like curves, to which they invite as plenary speakers, Neil deGrasse Tyson, David Deutsch, and the online Random Fictional Deepak Chopra Quote Generator. (Example from that last one; “Your desire embraces innumerable photons.”)

Later in the month T-Wave will announce that have finally built a working quantum computer, the T-Wave 4Z, capable of solving intractable mathematical problems of tremendous practical importance. Nobody will believe them. Nevertheless, MIT Prof. Aaron Scottson will write a fiery blog post condemning the announcement. The United States will continue for the rest of the year to not invest in photonic quantum information processing and therefore the Chinese will be the first to invent the quantum Internet, just in time for Christmas.

November — Chemistry


Chemists manage to coax a large sheet of graphene to grow into the shape of a Klein bottle, which is a topological oddity; namely a hollow three-dimensional object, with a two-dimensional surface, embedded in a four-dimensional space. The chemists name the new object the “funkyball”. A key property of any Klein bottle is that its inside is the same as its outside, so that it can never be bigger on the inside than on the outside. As the chemists run electrical tests on the new material to search for signs of semiconducting or even superconducting properties, they begin receiving strange signals from the funkyball that seem to be intelligent in origin. Having nowhere else to turn, they call in Jody Foster, who explains that the signals are in fact repetitions of the first million digits of pi in base three (or perhaps the first million digits of three in base pi). The chemists have inadvertently opened a trans-dimensional portal and made contact with extra-dimensional beings that live in spatial dimensions four through six. As the days go by, a rudimentary simultaneous translator is developed that allows the chemists to communicate with the beings in Morse code (base pi).

Things go well for a while. For example the chemists learn that the extra-dimensional beings are composed entirely of dark matter and have hitherto only interacted with our own universe gravitationally. The transdimensional beings amusingly note that in dimensions four through six, our own universe back here is considered to be made of what they call dark matter that acts only gravitationally with them.

Matters take a turn for the würst when the human chemists reveal that on Earth people still eat meat while the shocked extra-dimensional aliens declare that they are all vegans. Terrified that our meat-eating ways might corrupt their young, the aliens decide to destroy all human and animal life in our universe by attempting to send an army of self-replicating killer nanobots from the fourth dimension through the funkyball and into our domain.

In the nick of time the chemists call in an elite squad of militant carnivorous topologists, who succeed in convincing the chemists to cut funkyball in half using an ion beam. This well-known topological operation reduces the Klein bottle into two Möbius strips; two, one-sided, two-dimensional objects embedded in ordinary three-dimensional space. Their swift action cuts off the portal to the fourth dimension, destroying all the nanobots in mid-transport, and saving our universe.

The chemists and the topologists share the 2016 Fields medal.

December — Earth Science


NASA earth scientists will declare 2016 to be the hottest year on record (after declaring both 2014 and 2015 to also be the hottest years on record). Senator James Inhofe, Chair of the Senate Environment and Public Works committee, will call a joint session of congress, and subpoena NASA and other climate scientists to testify before it, to allow the Senator to protest the NASA scientists’ findings. Having trouble finding a snowball this time around, as it is 83°F in Washington DC on that day in December, Senator Inhofe drives to the nearby Dairy Queen ice cream shop in Arlington, Virginia, and purchases a vanilla ice cream milkshake, which he then dutifully totes back to congress and displays on the floor, claiming, “Ladies and gentlemen this ice cream milkshake is proof that global warming is a hoax!” He then hurls the milkshake at the head of Minority House Leader, Nancy Pelosi. Congresswoman Pelosi is, however, more agile than Inhofe gives her credit for, and she ducks. The milkshake instead hits Speaker of the House, Paul Ryan, squarely on his newly bearded jaw. Since Dairy Queen ice cream milkshakes contain neither ice cream nor milk, but rather Plasticine-like substances more akin to Epoxy and Elmer's Glue, the white milkshake sticks to Congressman Ryan’s beard and hair, making him look for all the world like Santa Claus.

The entire incident is broadcast on live television worldwide and millions of confused children begin to telephone Congressman Ryan’s office number with their Christmas lists. In desperation, Congressman Ryan contacts The Official NORAD Santa Tracker for help. NORAD agrees to automatically forward the calls to their own Santa Claus Christmas list phone number, which they have been using since 1955, and to track now both Santa Claus and Paul Ryan on Christmas Eve to soothe the nerves of all the confused children. The standard NORAD videos of 24 hours of Santa zipping around the globe in his flying sleigh and delivering presents delight children the world over, as usual. The NORAD videos of Congressman Ryan were less popular, as they showed that he spent most of Christmas Eve working out at the gym and lighting candles over the tomb of Ayn Rand.

Tuesday, May 5, 2015

Boson-Sampling-Inspired Quantum Metrology

Our group at Louisiana State University has teamed up with researchers at Macquarie University in Sydney and Boise State University in Boise to produce an new publication in Physical Review Letters, entitled, “Linear Optical Quantum Metrology with Single Photons: Exploiting Spontaneously Generated Entanglement to Beat the Shot-Noise Limit.” For regular readers of this blog, you will know that Boson Sampling is a new paradigm in quantum computing whereby single photons, inputted into a linear optical interferometer, can carry out a mathematical sampling problem that would be intractable on classical computer. The buzz surrounding Boson Sampling is that, unlike universal linear optical quantum computing, the experimental implementation requires no special quantum gates, like controlled-NOT gates, nor feed forward nor teleportation or any other fancy stuff. Identical single photons rattle around in the interferometer and they are sampled in the number basis when they come out. Sounds simple, but a classical machine cannot efficiently simulate the sampling output, whereas the linear optical device does this quite easily. For our recent review on Boson Sampling the reader is encouraged to go here.

In spite of all the excitement about Boson Sampling as a new paradigm for quantum information processing, the Boson Sampling problem has no know practical application to any mathematics problem anybody is interested in. In some ways the situation is similar to the late 1980s and early 1990s, before Shor’s invention of his factoring algorithm, when the first quantum algorithm shown to give an exponential speedup was the Deutsch-Jozsa (DJ) algorithm that allowed one to tell if a function was balanced or unbalanced. While a very nice result, nobody really gave a rat’s ass whether a function was balanced or unbalanced. It was however hoped that the DJ algorithm was just the tip of an iceberg and indeed the rest of the iceberg was revealed when Shor’s factoring algorithm was discovered. That was an (apparent) exponential speedup on a problem that people cared deeply about.

So too do we hope that Boson Sampling is just the tip of the iceberg when it comes to the power of linear optical interferometers, with simple single-photon inputs, to carry out tasks that are not only impossible classically but also of practical interest. In that direction our paper makes a frontal attack on the berg with a metrological ice axe. The idea emerged from the understanding that in Boson Sampling, an exponentially large amount of number-path entanglement is generated through the natural evolution of the single photons in the interferometer via repeated implementation of the Hong-Ou-Mandel effect at each beam splitter. It has been known for nearly 30 years the number-path entanglement is a resource for quantum metrology, beating the shot-noise limit, and so it was natural for us to ask if this hidden power in linear optics with single photon inputs might be put to work for a metrological advantage. Our paper shows that this is indeed the case.

To briefly summarize our scheme, we send a sequence of single photons into linear optical interferometer that contains an interferometric implementation of the Quantum Fourier Transform coupled with a bank of phase shifters with an unknown phase that is to be measured. Our signal consists of a sampling of the outputs tuned to the same sequence of single photons emerging from the exit ports. The signal-to-noise analysis was quite challenging as it involves the computation of the permanent of a large square matrix with complex entries. While in general this is classically intractable, to our surprise, something about the structure of the Quantum Fourier Transform seems to allow the permanent to be computed analytically in closed form. As least we conjecture this is so. We were able to eyeball a closed form formula for the permanent of a matrix of any rank and confirm it out to rank 20 or so numerically, but a rigorous mathematical proof of the permanent formula is still wanting.

Once we had the signal and variance analysis carried out, we were able to show (carefully counting resources) that the sensitivity of the device, which we christened the Quantum Fourier Transform Interferometer, is well below the classical shot-noise limit. It has been known for years that exotic number-path entangled states, such as N00N states, can beat the shotnoise limit, but N00N states are resource intensive to create in the first place, requiring either very strong Kerr nonlinearities or non-deterministic heralding. Here in our new paper we get super sensitivity for free from the natural evolution of single photons in a passive optical linear interferometer. This then seems to be the first example of the Boson Sampling paradigm providing a quantum advantage in an arena of importance, which is quantum metrology.

 Who knows what is left on this iceberg still yet unexplored?

Saturday, April 18, 2015

UK National Strategy for Quantum Technologies

Just winding up a one-week trip to the UK where I attended the Bristol Quantum Information Technologies (BQIT) Workshop at the kind invitation of the organizers. There was some disagreement how the acronym BQIT should be pronounced but upon my arrival we instantly all agreed it should be B-QuIeT. The workshop was a lively set of short talks interspersed with panel discussions and it was the first time I heard in some detail about the new UK National Strategy for Quantum Technology from non-other than Sir Peter Knight himself, who was a speaker on one of the panels focusing on the UK Quantum Hubs Network. There was quite a bit of excitement in the air as Simon Benjamin (University of Oxford, Quantum Computing Hub) gushed effusively about writing a 12-page proposal that came in at £3 million per page! 

There are four hubs dotting the UK countryside from Scotland to England with a total five-year budget of £120M for all four of the hubs with foci in quantum communications, imaging, sensing, and computing. And to complement these hubs are at least three new quantum technologies doctoral training centers. The budget for the training centers was less clear but I suppose all together this is close to £200M for five years potentially renewable in five years for another five. And that is, folks, as they say, new money.

All this activity seems to be coordinated by the UK Quantum Technologies Strategic Advisory Board, chaired by Prof. David Delpy, which has laid out a vision for a coordinated strategy in quantum technologies development in the UK.

It is somewhat disheartening to see all of this activity in the UK from the perspective of a research in the US, where the congress and the president can’t even seem to pass any new budget at all from year to year. I wish the UK program well and I did hear that each hub has set aside funds for international collaborations and so I hope this will be the first of several trips to visit my quantum friends and colleagues on the far side of the big pond. 

For young researchers interested in doing PhD or postdoctoral work in quantum technologies, you should follow your noses and follow the money. The UK seems to be the place where the quantum of action is at these days.