• ER = EPR?

    John F. Lindner

    This month is the 100th anniversary of Albert Einstein’s November 1915 discovery of the gravitational field equations of General Relativity, in which test masses move along the straightest possible paths (called geodesics) in spacetime curved by the density and flux of energy and momentum (including mass and pressure). General Relativity allows spacetime to be topologically doubly connected. In the “wormhole” depicted below (using two different embeddings), the distance across the flat region may be large even if the distance through the tube is small. Traversable wormholes, like the one in the movie Interstellar, might be propped open by exotic matter of negative energy density and provide shortcuts across the universe. Such structures are sometimes called Einstein-Rosen bridges, after a 1935 paper by Einstein and Nathan Rosen.

    A wormhole is a geometry of four-dimensional spacetime in which two regions of the universe are connected by a "shortcut" consisting of two "mouths" connected by a short narrow “throat”
    A wormhole is a geometry of four-dimensional spacetime in which two regions of the universe are connected by a “shortcut” consisting of two “mouths” connected by a short narrow “throat”

    Also this month, several research teams reported the best yet experimental realizations of quantum entanglement, in which pairs of particles interact so that each particle cannot be described independently regardless of their separation. For example, an electron and positron in the ground state of positronium can annihilate into two oppositely traveling photons whose spins are completely correlated, so that measurement of one spin determines the other even if the measurements are spacelike (or so far apart that no signal could connect them). In the visual metaphor below, a Necker cube outline can be interpreted two ways, representing a photon in a superposition of two spins; similarly, a pair of Necker cubes can be interpreted two ways, representing measurements of its correlated parts. Such “spooky action at a distance” is sometimes called an EPR correlation after another 1935 paper by Einstein, Boris Podolski, and Rosen.

    Single ambiguous Necker cube is a metaphor for quantum superposition, while a pair of ambiguous Necker cubes is a metaphor for quantum entanglement
    Single ambiguous Necker cube is a metaphor for quantum superposition, while a pair of ambiguous Necker cubes is a metaphor for quantum entanglement

    Recent discussions of the black hole information paradox and the holographic principle in anti-de-Sitter-space model universes suggest a relationship between wormholes and quantum entanglement that may elucidate the nature of spacetime itself: Can Einstein-Rosen bridges explain Einstein-Podolski-Rosen correlations? Is ER = EPR?

  • The Martian

    John F. Lindner

    Ridley Scott’s The Martian (2015) is the best Mars movie I have yet seen. Genuinely faithful to Andy Weir’s popular novel, The Martian chronicles astronaut Mark Whatney’s struggle to survive on Mars, after being accidentally stranded there, and the efforts by NASA and Whatney’s crew to rescue him. The story emphasizes the problem-solving character and skill of scientists and engineers in the celebrated tradition of the Apollo 13 rescue.

    Actor Matt Damon plays astronaut Mark Whatney marooned on a largely realistic Mars
    Actor Matt Damon plays astronaut Mark Whatney marooned on a largely realistic Mars

    I especially like the scenes of Whatney living, farming, walking, and driving on a mostly realistic Mars, with a near-terrestrial day-night cycle, authentic dust and sand and sky, including high wispy clouds and dust devils. I’d prefer less atmospheric pressure and sounds in Mars’ thin air (and space’s vacuum), more radiation protection and dust mitigation, and water from heating regolith (= soil) rather than catalyzing and burning hydrazine (= N2H4). I’d also like more accurate 0.38g surface gravity on Mars and more natural microgravity aboard the Hermes interplanetary spaceship (whose size and complexity I’d decrease while reducing the crew from 6 to 4).

    Indeed, The Martian makes me eager for more, especially for the real thing. I remember pausing one night to stare at the moon when people briefly lived on its surface during the Apollo program, and alongside that thrilling memory is the longing for another: to gaze at the ruddy dot of Mars amidst the stars while knowing other people live there — or to live there myself. As SpaceX founder Elon Musk said, it would be wonderful to be born on Earth and die on Mars*.
    —————–
    * But not in the landing.

  • 19th Century Foreground, 20th Century Background

    John F. Lindner

    Although some early aviation aficionados allege other flights (or hops) preceding the Wright brothers’ experiments at Kitty Hawk on 1903 December 17, the Wright Flyer did fly four times that day, including a final flight nearly one minute long, with the Wrights famously photo documenting their progress. They never flew that first aircraft again. Instead, they went home to Dayton Ohio and built the successively better Flyer II and III and the Model A. Using those aircraft, Wilbur and Orville Wright became the first to fly for one minute, the first to fly for two minutes, for half an hour, for one hour, and for two hours. In fact, all world record flight times between 1903 and 1909 were set by the Wright brothers. They truly were first in flight.

    The Wrights became world famous when they demonstrated their flying machines in Europe in 1908-1909. Wilbur went first and was later joined by brother Orville and sister Katherine. Crowds came to watch them; even King George of England crossed the channel to France to see the modern miracle of flight. In the accompanying photo, farmers with an ox cart pause to watch Wilbur Wright and a passenger fly overhead, the 19th century foreground contrasting with the 20th century background.

    Wilbur Wright instructing a student pilot in Pau, France, passes over an ox cart in 1909
    Wilbur Wright instructing a student pilot in Pau, France, passes over an ox cart in 1909

  • Guest Blog – Nathan Johnson ’16

    Susan Lehman

    Over the past century or so humankind has achieved remarkable feats of science and engineering – at a cost. The impact that our innovations have on the environment has become exceedingly clear. As we progress toward better and faster ways to travel we need to be cognizant of the efficiency and impact of our modes of travel.

    This past summer, I was fortunate enough to be on a team that was working toward new and better aircraft engines. At NASA’s Glenn Research Center, I worked with a research engineer on new materials for General Electric’s GE90-class turbofan aircraft engines. The division I worked for has been developing composite materials to replace metal alloys in the hottest parts of the engine. These composite materials are lighter, stronger, and can burn fuel at higher temperatures and efficiencies, reducing the fuel consumption. All in all, these composites are a huge step forward for engine efficiency.

    But, as with any new and exciting invention, there was a caveat. The new composite materials degrade in the presence of oxygen and water vapor – a huge problem considering that water vapor is a major byproduct of jet fuel consumption. To combat this erosion, I worked on environmental barrier coatings (EBCs). These EBCs are just what their name implies: they act as a barrier between the composite and the aircraft engine environment. Many exciting candidates for EBCs exist, namely rare-earth silicates. For 10 weeks this past summer I tested the fundamental reaction kinetics of some of these materials in the presence of many different substances commonly ingested by aircraft engines, such as sand or ash. EBCs need to be stable at very high temperatures and for long periods of time.

    A Yttrium-based EBC
    This is a sample of a Yttrium-based EBC material after being heated to 1200 deg Celsius for 20 hours. It was heated in the presence of desert sand.

    It was one of the most rewarding and exciting experiences of my life. Not only was I working on a project that is having a huge, immediate impact (these composite materials are being implemented in Boeing aircraft in the coming year) but I also got to work in one of the coolest, most exciting workplaces ever. The engineers and scientists at NASA are the rockstars of aeronautics. My advisor was a young, excited, and brilliant woman who inspired me to work extremely hard and go for my absolute best. NASA opened my eyes to a whole new world of possibilities for my future – including a career at NASA. While getting a position at a NASA center is no easy task, it is something I will certainly be working toward for years to come.

    The summer was a whirlwind of new experiences, new topics, and a whole lot of learning. I walked away with everything I hoped to gain and so much more. The project ended well and persuaded me to consider a wide range of areas for my graduate studies. In the end, the EBCs I worked on ended up not being viable candidates – but hey, that all a part of research.

  • On the Shore of the Arctic Ocean

    John F. Lindner

    It was a privilege to spend the 2014-2015 academic year and summer on sabbatical at the University of Hawai’i in Honolulu. During the last week of July, I stood on the spectacular beach at Kailua near sunset and said to myself “wow, wow, wow”. A week later, on my way home, I stood on the dramatic shore of the Arctic Ocean in Barrow Alaska, the northernmost U.S. settlement in a 45°F rain, a comparably singular experience. The sun set that the day for the first time since May, but due to the cloud cover, I never saw it, as an undirected light illuminated the sky and mud and utilitarian buildings. I returned to the beach the next day, and the heavy winds of the night before had littered the shore with meter-sized icebergs. The native Iñupiat people still practice subsistence whaling, and Barrow is home to some Pacific islanders, including Hawaiians.

    On the shore of the Arctic Ocean, Barrow Alaska, August 2015, 45°F and raining
    On the shore of the Arctic Ocean, Barrow Alaska, August 2015, 45°F and raining

  • Guest Blog – Spencer Kirn ’16

    Susan Lehman

    Robotic Arm

    This summer I have been working with Dr. Chris Crawford at the University of Kentucky. We have been trying to design a cosine theta coil, which is a magnetic coil that has a uniform magnetic field on the inside, but no field on the outside. Beyond this, we also wanted to create this magnet using without using wires on the endcaps. To do this we would need to drill circuit boards that carried surface currents through them. To create the circuit boards we used a drill mounted on a robotic arm (pictured without the drill attached) to drill through special current carrying materials.

    Through the summer most of our time has been taken up by learning the programing system that had been created over the past several years of the project on MatLab, calibrating the various aspects of the robot so we could very accurately tell the robot where to drill, and finally actually designing the endcap. By the time I was finished we had gone from barely being able to get the robot to draw on a whiteboard to being able to drill basic designs for the magnet. We had also just finished the first full design of the magnet. Unfortunately I was not able to stay long enough to drill it and be able to test it, but the next team should be able to accomplish that soon!

  • Wooster Physics in Prague, Glasgow, and Oxford!

    Cody Leary

    Greetings!  I have recently returned from a semester-long research leave, thanks to Wooster’s generous faculty leaves program.  During my leave, I split my time between Wooster and the Universities of Glasgow and Oxford in the United Kingdom, in addition to a week-long conference in Prague, Czech Republic.

    In Wooster, I continued work in my lab with Clare Boothe Luce scholar Maggie Lankford ’16, developing the means to manipulate the degrees of freedom of photons (quantum particles of light) in previously unrealized ways.  This work has applications in the current push to realize new types of computational networks based on quantum mechanical principles.

    At the Prague conference (Quantum Optics and Quantum Information Transfer and Processing), I coauthored a conference paper along with Maggie and Wooster graduate Deepika Sundaraman ’14 entitled “Coupling of spin and orbital degrees of freedom in tunable Hong-Ou-Mandel interference involving photons in hybrid spin-orbit modes.”  The paper was inspired by predictions and preliminary results achieved by Deepika in her Senior IS thesis, which Maggie has continued to investigate.  Maggie also attended this conference, where she presented our work in poster form.

    View of Prague Castle and Charles Bridge crossing the Vltava River. I took this picture from the top of the Petrin tower.
    View of Prague Castle (left) and Charles Bridge crossing the Vltava River (right). I took this picture from the top of the Petrin observation tower.

    In Glasgow and Oxford, I worked with collaborators Dr. Sonja Franke-Arnold and Dr. Brian Smith, familiarizing myself with newly developed technologies for the manipulation of photons by optical means.  The leave has led to new research directions involving spatial manipulation of polarization and phase structures of light, which have collectively contributed to a National Science Foundation grant proposal that I submitted this summer.  I expect these new directions to become the subject of one or more exploratory IS projects at Wooster during the coming year.

    The University of Glasgow's main tower, which overlooks Kelvingrove park. the famous physicist William Thompson (also known as Lord Kelvin), had his lab near the tower.
    The University of Glasgow’s main tower, which overlooks Kelvingrove park. The famous physicist William Thompson (also known as Lord Kelvin), had his lab at the University, which is the fourth oldest in the English-speaking world.

    Outside the laboratory, a few highlights of my UK trip include:

    1) an ascent to the summit of Sgurr na Stri on the Isle of Skye, which gave way to an amazing view of the main ridge of the Black Cuillin mountain range curling round Loch Coruisk;

    The Black Cuillin range as seen from Sgurr na Stri on the Isle of Skye.

    and

    2) a trip to the 500+ year old Bodleian Library in Oxford where they had original copies and first editions of many works of genius, including this first edition of Sir Isaac Newton’s Principia!

    Newton's Principia, original Latin edition! Edmond Halley, who persuaded Newton to publish, became the editor of the work, and wrote the poem on the left page to preface the text.
    Newton’s Principia, original Latin edition! Edmond Halley, who persuaded Newton to publish, became the editor of the work, and wrote the poem on the left page to preface the text.

    I am excited to be back in Wooster, and look forward to the adventures that the coming year will bring.

  • Rubik’s Cube Puzzles

    John F. Lindner

    As a kid, I enjoyed solving the “15 puzzle”, a sliding puzzle consisting of a 4×4 grid of 15 squares. However, I was amazed by a kind of 3D analogue of the 15 puzzle: Ernö Rubik’s 1974 masterpiece, which is both a seemingly impossible mechanism (how does it not fall apart?) and a silent challenge (one knows immediately what needs to be done). It took me about a month to solve my first Rubik’s cube. I got a notebook, created a move notation, and filled it with formulas like FRUR’U’F’ and LU’R’UL’U’RU2. I was never a speed cuber, but I learned to easily and efficiently solve the cube from generic initial conditions. Years passed and my cube skills lapsed, until visiting professor Nelia Mann showed me her collection of 3D twisting puzzles. Better technology had enabled a new generation of Rubik’s cubes that turned easily and were stickerless. I determined to devote part of my University of Hawai’i sabbatical to reviving my puzzle skills.

    My Hawai'i toy collection
    My Hawai’i toy collection

    Using resources online, I first mastered the 4-layer Revenge Cube followed by the 5-layer Professor Cube (and I had already mastered the 2-layer cube, which uses a subset of the 3-layer algorithms). I enjoyed the Mirror Cube, which is a cool variation, where shape replaces color. A related puzzle, which I found fun to manipulate but easy to solve, is the Gear Cube. Many years ago, math professor Pam Pierce lent me her Square-1 puzzle, which has a daring diagonal move, but I never had time to solve it. I’m pleased to report that I now can efficiently solve the Square-1, whose algorithms look like /(3,-3)/(0,3)/(-3,0)/(3,0)/(-3,0)/. Finally, I learned to solve the dodecahedral Megaminx, which has a different permutation group, but is still closely related to the cubes. The Megaminx is my favorite puzzle after the original Rubik’s cube.

    I spend so much time working at a computer, it’s nice to interact with these wonderful mechanisms. Many more such puzzles await my next sabbatical. In the photo, in addition to the twisty puzzles, you see 5 juggling balls, which I learned to juggle during my previous sabbatical at the University of Portland. The Rubik’s cube mug is fully functional (as a mug), and I use it all the time — thanks Johanna!

  • Guest Post: Michael Wolff ’17

    Susan Lehman

    When I first came to Wooster, I had no clue what discipline I would explore, and didn’t even take my first physics class until the second semester of my freshman year; now, I’m coming up on the end of my second month conducting research at Michigan State’s National Superconducting Cyclotron Laboratory (NSCL), one of the nation’s top nuclear science research labs. Not only has it been a wonderful period of growth for me as a physicist, it’s also the first experience I’ve had living alone in a new place for any significant length of time. It’s been a long, rewarding journey, and I continue to learn new things and expand my horizons nearly every day.

    During my time here, it has been my privilege to work with Dr. Fritsch and the rest of the AT-TPC detector group. The “AT-TPC” stands for ”Active Target Time Projection Chamber,” which means that it’s filled with a gas that both reacts with the beam of particles shot into the detector, and also serves as a medium to track the reaction.

    The Prototype AT-TPC (at the top middle of photo) in its natural habitat
    The Prototype AT-TPC (at the top middle of photo) in its natural habitat

    My first week or so at the lab, I spent most of my time reading papers on the AT-TPC and other detectors, catching up so I could better understand the work I would be doing. Since then, most of my time here has been spent in the lab, working with another undergrad researcher from France to perform tests on the smaller Prototype AT-TPC (PAT-TPC), as shown above. Though I had high expectations coming in, I’ve actually been surprised by how much time I’ve spent in the lab, hands-on with the equipment. Last week, we packed up the prototype and sent it to the nuclear physics lab at Notre Dame, where we’ll be conducting an experiment next week. Even in the last few days of my research position, I’ll be going new places and experiencing new things.

  • It’s Geology, But Not As We Know It

    John F. Lindner

    In a famous Star Trek misquotation, Mr. Spock says to Captain Kirk, “It’s life, Jim, but not as we know it”. Well, yesterday the New Horizons spacecraft returned its first closeup of Pluto, and it’s geology, but not as we know it.

    Tombaugh Regio on Pluto (left) and a closeup of 2-mile high water-ice mountains (right).
    Pluto’s Tombaugh Regio (left) with 2-mile high distinctly non-terrestrial water-ice mountains (right).

    The Tombaugh region of Pluto contains a craterless expanse dotted with two-mile high mountains. The nitrogen, methane, and carbon monoxide ices that cover much of Pluto’s surface are not strong enough to support such tall mountains, but water ice at Pluto’s frigid temperatures is, and it is water ice that must form the bedrock or “bed-ice” of these mountains.

    What generates the heat that continues to erase Pluto’s craters against planetary bombardment? It can’t be tidal forces, like those that generate Io’s volcanoes at Jupiter, because nearby Charon is too small and in tidal equilibrium with Pluto. Possibilities include Pluto’s heat of formation, from a big “splat” that formed Charon and its smaller moons, or radioactivity from the uranium and thorium in the silicates in its interior, which must be present to account for Pluto’s relatively high density. A more provocative proposal is a global interior liquid water ocean that is gradually freezing and whose latent heat drives geysers or cryovolcanism while dredging up nitrogen and methane to replenish Pluto’s tenuous atmosphere, which is rapidly escaping to space. Stay tuned!

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