Pittsburgh Husband and Wife Develop a Different Sort of Knowledge
for the Next Generation of Computing

Quantum Couple – Jeremy Levy and Chandralekha Singh explore the far reaches of the physical world. He conducts research in the arcane field of quantum computing, She explores innovative methods of teaching burgeoning physicist how to think about the world of quanta.

by Tom Imerito

He grew up in Manhattan.  She – in Patna, India.   Both were taken with the way physics accounts for the world around them.  After completing undergraduate studies at Harvard and the Indian Technology Institute, they met as first year physics doctoral students at the University of California, Santa Barbara.  Upon arrival she found herself the sole woman among thirty-six male classmates.  Searching for a female companion, she pored over the class roster.  A first and last name ending in the letter Y caught her attention because in her native India, Y is a female suffix.  She tracked down the classmate only to find that it was just another of her thirty-six male colleagues.  But despite her initial disappointment, fortune smiled on her. The classmate with the Ys turned out to be Jeremy Levy, the man Chandralekha Singh would marry eighteen months later.

Today they are professors of physics at the University of Pittsburgh and live with their teenage sons, Akesh and Ishan, in Schenley Farms, adjacent to Pitt. Jeremy explores the far reaches of quantum computing, one of the most challenging and elusive disciplines in all of academia.  Chandralekha’s  (Chaun-Dra-Lay-Kah) experiments take place in the college classroom where she devises innovative ways to teach burgeoning physicists how to think about the infinitesimally small and intractably weird world of quantum mechanics – the rules of  how things smaller than atoms work.

A handsome couple to be sure, they can’t help but chuckle at nerdy physics jokes.  Chandralekha tells one about Neils Bohr, one of the founding fathers of quantum mechanics, who is stopped for speeding by a highway patrolman.  The trooper inquires, “Do you know how fast you were going?”  Bohr replies, “No officer, but I do know exactly where I was.”  The couple responds to my blank expression with kindly patience.  The joke is funny to quantum physicists, they explain, because it puts the man who gave us the orbital model of the atom in the mundane position of trying to beat a speeding ticket by invoking one of quantum mechanics’ most sacred mysteries and fundamental truths: You can know either the speed or the position of a quantum particle, such as an electron, but not both at the same time.

In a similar vein, Jeremy relates a story about teasing his 13-year old son, Ishan, who has managed, over a period of months, to memorize the first 500 decimal places of Pi.  He tells him that because Pi is an infinite number, he, Jeremy, can easily reel off 500 digits of Pi by simply naming any random sequence of numbers, reasoning that any string of numbers must necessarily be found an infinite number of times in an infinite number such as Pi.  The only catch is he cannot say precisely where his sequence might appear.  “It’s a math joke,” Jeremy explains sheepishly, as I force a smile to conceal my befuddlement. “It’s about infinity,” he adds.  “It’s a different sort of knowledge.”

Such different sorts of knowledge comprise the bulk of Jeremy and Chandralekha’s reality which is laden with  such notions as the well established fact that observing a quantum particle, changes it – not just optically or metaphorically, but really – physically; or that an electron can be in two places at one time – not very close by or in rapid succession – but in two completely different places at the very same instant; or that electrons can “tunnel” through solid objects; or that two unconnected subatomic particles can become entangled at long distances and communicate with each other.

Despite the impenetrably obscure nature of their chosen field of interest, Jeremy and Chandralekha each exhibit gifts for bringing the world of quantum physics within the grasp of mere Earthlings.  She demonstrates the effects of angular momentum with rotating bicycle wheels and spinning figure skaters.  He uses a child’s Etch-A-Sketch as a model for his sketched oxide single electron transistors.

In 2010, Levy was awarded a $7.5 million grant from the United States Air Force to develop a quantum computer.  Then in September of 2011, Levy and Singh were awarded a $1.8 million grant from the National Science Foundation and the Nanoelectronics Research Initiative (NRI) of the Semiconductor Research Corporation (SRC) to bring a new kind of computer out of the lab and into the real world. In addition to Levy’s innovation research, the grant includes funding for Singh’s educational research. In collaboration with colleagues, she is developing a new “OnRamp” education program aimed at lowering the steep and treacherous learning curve for early stage quantum physics researchers.

Jeremy’s innate appreciation of physics is evinced by his enthusiastic assertion that everything around us is based on quantum physics, from two-by-fours to cell phones.  But beyond its ubiquity, quantum mechanics holds very serious consequences for computers – and so, for all of us.

Although they are sure to differ from today’s computers in both the materials used to create and store data as well as in the processes used to operate on it, once quantum computers make the transition from laboratory bench to the real world, the most important difference will be speed.  Today’s computers use the physical on/off states of microscopic switches – transistors – to process the most basic information possible –binary data bits – on/off – yes/no – by means of sets of logical arguments or algorithms executed on PCs, laptops and smart phones.  In contrast to today’s computers, quantum computers are expected to use physically infinitesimal and computationally much more flexible bits of information called Q-bits which will enable the compression, consolidation, multiplexing and acceleration of advanced computing operations.  The result will be a computer with heretofore unimaginable speed.

Such an advance in processing speed is likely to have powerful consequences for Internet data security.  Because the strength of Internet security is based upon the length of time it would take the most powerful computer to crack a given encryption code, a vastly faster computer could change the game forever.  Experts estimate that today’s most secure encryption codes would take longer than the age of the universe to crack with today’s computers.  Since the universe has been around for more than 13 billion years, we’re in good shape as of right now. However, a quantum-speed computer could change things quickly by cracking any imaginable encryption code in short order, including those employed for top secret government communications and – closer to home – your personal financial transactions.  Clearly, whoever builds the first quantum computer will win the information technology sweepstakes.

In an effort to get there first, Levy (short ě) is focusing his efforts on developing a transistor the size of a single electron.  He begins with a layered pair of exotic materials that act as electrical conductors when they are four or more atomic layers thick, but serve as insulators at three or fewer. In a process that resembles a child’s Etch-A-Sketch, Levy “writes” and “erases” nanoscale circuits, roughly fifteen atoms wide, by adding and removing electric charges on the top surface of this new double-layered material using the ultra-fine-tipped electronic probe of an atomic force microscope (AFM).  By drawing a pair of intersecting circuits, at right angles and zapping the intersection with the AFM tip, Levy creates a tiny, 1.5 nanometer insulated trap in the all-but-non-existent space where the layers meet.  Inside the trap a group of negatively charged electrons become a synthetic atom known as a quantum dot. The remaining intersecting lines extending from the quantum dot become four leads which act as nanoscale circuits.  With a subsequent, positive zap, single electrons can be coaxed into tunneling through the insulating walls of the trap and into the leads.  Then with an oppositely charged zap, they tunnel back into the quantum dot again.  Because these trapped electrons can control electric current flowing into the leads, much the way a conventional transistor controls current into and out of its circuits in today’s computers, the result is a transistor that is several thousand times smaller than today’s.  Scaling things down even further, Levy is working on ways of using the direction of an electron’s spin (clockwise or counterclockwise) as a data bit – a Q-bit – the holy grail of quantum computing.

Although Jeremy and Chandralekha make understanding quanta look easy, for many students, the different sort of knowledge demanded by quantum topics stubbornly resists comprehension. In response, Chandralekha focuses her efforts on devising strategies to effectively teach students how to think about quantum mechanics, before actually teaching them the details of the subject.  She begins with what students already know and builds on that.  For instance, she gives students a real-life, long-term memory of the effect of angular momentum on spinning bodies as various as orbiting electrons and collapsing neutron stars by sitting students in a swivel stool and spinning them while they hold a dumbbell in each hand.   As they pull the dumbbells into their bodies, they spin faster as the energy of motion moves nearer the center of their bodies, just like figure skaters, subatomic particles and celestial bodies. It’s a practical lesson students can apply to their theoretical studies, in addition to being one they will remember throughout their careers.

At the Summer 2012 meeting of the American Association of Physics Teachers, Singh was awarded the association’s Distinguished Service Citation for her pioneering research in the teaching and learning of quantum mechanics.

The couple’s work promises to lead to a new paradigm of computing.  But unlike today’s computers, which are based on 0’s and 1’s this one started with a couple of Y’s.

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This story first appeared in the Fall 2012 issue of Pittsburgh Quarterly. You can read the original here.

Researchers Quantify Tissue Networks at McGowan Institute.

Dr. William Wagner (left), director of the McGowan Institute for Regenerative Medicine, reviews scanning electron microscope images of synthetic tissue scaffolds with researcher Antonio D’Amore.

By Tom Imerito

At their weekly meeting, Doctors William Wagner and Antonio D’Amore are reviewing progress on D’Amore’s efforts to transform images of biological tissue into mathematical data.

D’Amore’s work will be instrumental in engineering synthetic materials for implantation in patients suffering from tissue and organ insufficiencies.   For Wagner, who was named director of the McGowan Institute for Regenerative Medicine earlier this year, meeting with D’Amore is just one of a multitude of administrative tasks associated with managing the Institute as well as serving as lead investigator for his own group of a dozen-or-so researchers.

D’Amore shows his boss a skeleton-like map of a tissue fiber network detailing each fiber segment’s size, shape, position, angle, intersections, and overlaps along with their corresponding mathematical values.  He has produced the map by running a scanning electron microscope image through software filters he has developed.  The process is not only more accurate than human measurement – at three minutes per image it is forty times faster than the two hours of manpower it took previously.

D’Amore’s innovation comes at a perfect time.  Recently the focus of tissue engineering has shifted toward smaller components of the tissue generation mechanism, including D’Amore’s area of interest – the mechanical properties of the non-cellular collagen scaffolds, called extracellular matrices – into which cells implant themselves and multiply to form organs.

A native of Palermo, Italy, with a PhD in biomechanics and tissue engineering, D’Amore is also a fellow of The Ri.MED Foundation, an international partnership between the Italian Government, the Region of Sicily, the University of Pittsburgh, and UPMC.  He gravitated to McGowan as a result of its renown as a Mecca for regenerative medicine.  Similarly, twenty years earlier Wagner had gravitated to Pittsburgh for precisely the same reason.  UPMC and its academic partner, the University of Pittsburgh, had, and still has, all the essential ingredients for the continuously emerging field – transplant surgeons, medical specialists, research scientists, and engineers of every ilk – all of which attract an abundance of patients.  The only missing ingredient was, and continues to be, a sufficient supply of donor organs, which serves as the driving force behind McGowan’s three-pillar, patient-centric approach to the problem of replacing failed tissues and organs.

The first of the pillars is made up of intermediary assistive devices, such as heart pumps and artificial lungs, which are designed to keep patients alive while they wait for donor organs.  Next, the field of tissue engineering – D’Amore’s area of expertise – attempts to remedy tissue and organ deficiencies with both natural and synthetic substitutes.  Finally, stem cell therapy has emerged as a viable option due to the discovery of ways to coax adult stem cells to differentiate into a variety of organ cells.  But, rather than looking for ideal solutions for any one of these areas at some point in the future, McGowan mixes and matches all of them to improve the lives of individual patients today.

Click to expand

Scanning electron microscope images of biological extracellular matrix tissue scaffolds and synthetic electrospun polyester urethane urea tissue scaffolds.
Top: Fiber network and diameters detected by the algorithm, A) isotropic elastomeric scaffold, B) anisotropic elastomeric scaffold. Fiber network and diameters manually detected, C) isotropic elastomeric scaffold, D) anisotropic elastomeric scaffold.
Bottom: Detected fiber networks for A) isotropic elastomeric scaffold, B) anisotropic elastomeric scaffold, C) Rabbit MSC seeded collagen gel, D) Decellularized rat carotid arteries. (Click image for full size)

This eclectic, solution-focused approach is exemplified in an epiphany D’Amore had when he first arrived in Pittsburgh last year.   An astute amateur photographer, D’Amore was photographing a tree next to Pitt’s Cathedral of Learning when an unexpected connection between the structure of the tree and that of the fiber networks he was studying at work occurred to him.  While observing the tree’s branches against the sky, D’Amore realized that he was mentally defining the tree’s geometry by successively identifying the boundaries, intersections, sizes and directions of its branches.  It struck him that, using the same method his brain naturally used to define the tree, he could write a computer program to mathematically map tissue fiber networks much faster than any human could.  It wasn’t long before D’Amore’s work was published in the field’s leading journal, Biomaterials.

In an amazing feat of mathematical gymnastics, D’Amore extracts digital values from analog microscope images of biological tissue and converts them into computer control input values for a synthetic tissue scaffold fabrication system.  The fabrication process entails precisely depositing electrically atomized strands of a synthetic plastic called polyester urethane urea on a spinning cylinder at varying angles and directions to simulate the forms and performance characteristics of living tissue networks.  The resulting ES-PEUU scaffold (electrospun polyester urethane urea) can be seeded with stem cells during manufacture, ready for implantation and growth in a biological system.  Once inside a body the stem cells divide and populate the scaffold to produce new functioning organ tissue.  When the cells fully populate the scaffold, the synthetic material is absorbed by the body and eliminated.

Although the process is promising, it is still in the laboratory.  And although D’Amore’s innovation represents progress, the field of tissue engineering is still fraught with many more questions than answers.  But in the quest to improve human lives, nobody is looking more intently for solutions than Drs. Wagner, D’Amore and their colleagues at the McGowan Institute for Regenerative Medicine.

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Tom Imerito is president of Science Communications, a Pittsburgh technology public relations consultancy.  He can be reached at 412-892-9640 or thomas@science-communications.com.  To learn more about Science Communications, please visit www.science-communications.com

An abridged version of this article first ran in TEQ magazine. You can read it here:

How Discoveries at Meadowcroft Rock Shelter Changed the Date of the First Human Migration to North America

When Ages Collide

by Tom Imerito

Five decades ago beneath a rock overhang in Washington County, Pennsylvania the Atomic age collided with the Stone Age.  Since then, Meadowcroft Rock Shelter has been a focal point of archeological innovation and discovery as well as scientific controversy and iconoclasm.

The story begins on Nov 12, 1955, when a gentleman farmer and amateur archeologist named Albert Miller noticed some burnt bone and flint flakes among the dirt that a woodchuck had excavated while burrowing in the forest floor beneath a rock overhang on his farm.  His interest being piqued, Miller began digging.  At a depth of thirty inches he discovered a flint knife, which he recognized as an important archeological find.  Fearful of looting, he kept the site a secret for the next fifteen years while he sought professional archeological help. [Continue Reading…]

The Life and Times of Samuel Pierpont Langley

Time Stars Sun Spots and Flying Machines

by Tom Imerito

At the foot of the escalator on the first floor of Wesley Posvar Hall at the University of Pittsburgh a stately memento of the earliest days of aeronautics hangs from the ceiling in testament to the genius of its inventor, Samuel Pierpont Langley.  Dr. Langley came to Pittsburgh in 1867 to serve as director of the Allegheny Observatory and professor of physics and astronomy at the University.  Langley’s scientific intuition, practical resourcefulness and an unrelenting inclination to look at things with a fresh eye made him famous around the world. [Continue Reading…]