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  • Exciting Adventures in Coupling | JILA-PFC
    lab operated by the Jin and Ye groups According to the Rey theory group and its collaborators ultracold dipolar molecules can do even more interesting things than swapping spins For instance spin swapping occurs naturally when ultracold potassium rubidium KRb molecules are in two of their four possible excited and ground states The differences in two states are sufficient to cause a spinning molecule to slow down at the same time another molecule begins to rotate The exciting news is that when two KRb molecules are in three of the four possible states they don t just swap their spins The direction of the spin in the molecule that starts rotating gets reversed This more elaborate spin swapping affects the motion of the molecules a phenomenon known as spin orbit coupling Spin orbit coupling is something that happens in solids when electrons move inside the electric field of a crystal This process is the key to understanding spin transport and spin currents which are analogs of electron transport and electric currents Spin orbit coupling also plays a role in some very exotic phenomena such as the creation of a Majorana particle which is its own antiparticle The theorists responsible for discovering these exciting new adventures in spin orbit coupling are research associates Sergey Syzranov and Michael Wall CU Associate Professor of Physics Victor Gurarie and JILA Fellow Ana Maria Rey Their discovery of spin orbit coupling in ultracold molecules was reported online in Nature Communications on November 7 2014 The next step in this research is finding a model system for learning how to implement and control spin orbit coupling And the JILA ultracold KRb experiment is ideally suited for this purpose For example KRb molecules are polar which means that the K end of one molecule attracts the Rb

    Original URL path: http://jila-pfc.colorado.edu/highlights/exciting-adventures-coupling (2016-04-29)
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  • The Quantum Identity Crisis | JILA-PFC
    at zero temperature shifts between completely distinct forms For instance one kind of quantum phase transition takes place when a researcher uses lasers to force atoms from a Bose Einstein condensate BEC inside a crystal of light where the atoms solidify into a lattice pattern Because the ground state arrangement of the atoms has totally changed from the indistinct blur of a BEC to a regular array inside the light crystal the physical manifestation of the atoms is completely different We now know that quantum phase transitions also occur in dynamical systems thanks to the Holland group Dynamical systems are systems that can be a long way from equilibrium like atomic clocks clocks that are always evolving in time or superradiant lasers that have photons continuously moving in and out of them Not surprisingly all sorts of things happen in such dynamical systems when they change their quantum phase The new understanding of dynamical quantum phase transitions was gained during the Holland group s theoretical investigation of the quantum aspects of classical synchronization Classical synchronization theory explains why fireflies suddenly start emitting light simultaneously crickets spontaneously sing in unison metronomes or pendulum clocks synchronize their ticking if they re physically connected or why audiences clap in unison after a minute or two To study the effects of quantum synchronization as compared to ordinary everyday synchronization the Holland group looked at what would happen if two atomic clocks containing identical ensembles of atoms moved close enough to one another to merge into a single larger atomic clock The group discovered that things got really interesting when the clocks moved very close together Suddenly it was as if every atom in both clocks was trying to decide Should I be in a separate clock or in one clock The quantum noise from

    Original URL path: http://jila-pfc.colorado.edu/highlights/quantum-identity-crisis (2016-04-29)
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  • Atoms, Atoms, Frozen Tight in the Crystals of the Light, What Immortal Hand or Eye Could Frame Thy Fearful Symmetry? | JILA-PFC
    the Rey group and recently observed by the Ye group Credit The Ye and Rey groups and Steve Burrows JILA Symmetries described by SU N group theory made it possible for physicists in the 1950s to explain how quarks combine to make protons and neutrons and JILA theorists in 2013 to model the behavior of atoms inside a laser Now the Ye group has observed a manifestation of SU N 10 symmetry in the magnetic behavior of strontium 87 87 Sr atoms trapped in crystals of light created by intersecting laser beams inside a quantum simulator originally developed as an optical atomic clock This first ever spectroscopic observation of SU N orbital magnetism in 87 Sr atoms cooled to micro Kelvin temperatures was reported online in Science Express on August 21 2014 Several advances made this observation possible 1 Seminal theory work by the Rey group predicting the magnetic behavior of 87 Sr atoms at cold and ultracold temperatures 2 Exquisite measurement precision available from an ultrastable laser developed for the 87 Sr lattice optical atomic clock 3 The ability to freeze out the motional states of the atoms but preserve the flow of information at relatively high μK temperatures 3 The use of 87 Sr atoms whose 10 nuclear spin states are decoupled from their interparticle interactions and 4 The experimental control of the number of 87 Sr atoms in the ground and excited electronic states used as orbitals This groundbreaking work opens the door to 1 precision studies of collisions between nearly identical 87 Sr atoms that differ only in the states of their nuclear spins 2 a deeper understanding of the role of atomic orbitals in collisions and chemical reactions and 3 investigations of quantum magnetism and exotic materials For instance theorists have predicted that a chiral

    Original URL path: http://jila-pfc.colorado.edu/highlights/atoms-atoms-frozen-tight-crystals-light-what-immortal-hand-or-eye-could-frame-thy-fearful (2016-04-29)
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  • Quantum Entanglement | JILA-PFC
    no amount of squinting makes this quantum blurriness go away What the Thompson group has done is to figure out how to create the right kind of eyes to measure the quantum fuzziness in 500 000 rubidium Rb atoms and reduce it by a factor of 10 This exciting result was the largest directly observed measurement enhancement due to entanglement ever reported for atoms It appeared online in Nature Photonics this week The research team responsible for this work included recently minted Ph D Justin Bohnet graduate students Kevin Cox Matt Norcia and Josh Weiner recent JILA grad Zilong Chen and Fellow James K Thompson One way to think about this experiment is that a measurement squeezes the quantum noise Squeezing means that the researchers were able to design the measurement technique to preferentially force quantum noise out of the width of their quantum clock hand and into its length instead A narrower clock hand allows one to read the clock more precisely At the same time more noise in the length has no bearing on a measurement of time The reason squeezing works is because the Thompson group s measurement of quantum fuzziness entangles the atoms In a large entangled state the fuzziness of each individual atom is partially cancelled by the fuzziness of other atoms As a result the overall fuzziness of all the entangled atoms is reduced So if precision measurement specialists entangle independent atoms there are clever ways to make them work together And when they work together they can become a clock with higher precision than would be possible if all the atoms were separately trying to measure the exact time as well as length or another physical quantity The Thompson group was able to make an entangled collection of atoms by allowing all the

    Original URL path: http://jila-pfc.colorado.edu/highlights/quantum-entanglement (2016-04-29)
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  • Invisible Rulers of Light | JILA-PFC
    with extreme ultraviolet light according to Ye s colleagues in precision measurement and laser science This research was reported online in Nature Photonics this week The invisible rulers of light are a pair of XUV frequency comb lasers that work in tandem A frequency comb is a light source whose spectrum consists of a series of equally spaced teeth which are like the tics on a ruler except that they measure frequency and are much closer together The invention of the optical frequency comb in 2000 has already transformed precision measurement with visible light The same transformation is now set to happen with XUV wavelengths of light 124 10 nm It s not surprising this advance occurred in the Ye labs where the new work could increase the spectral resolution of any XUV source by 10 millionfold What s real is what you measure if you re measuring well says Fellow Jun Ye And now what we can measure precisely with visible light we can do just as well in the extreme ultraviolet We hope that one day we will be able to shine XUV comb light on nuclear matter and change its states The team responsible for this stellar advance in precision measurement includes graduate student Craig Benko former research associates Tom Allison Stony Brook University and Arman Cingöz AOSense research associates Linqiang Hua and François Labaye former graduate student Dylan Yost Colorado State University and Fellow Jun Ye The pair of XUV combs will be able to make precision measurements of atomic nuclei atoms charged ions and simple molecules Such measurements require XUV laser light that is coherent and stable Until now it wasn t clear that there would ever be a ruler of light in the XUV frequencies like there is in the visible Since no person

    Original URL path: http://jila-pfc.colorado.edu/highlights/invisible-rulers-light (2016-04-29)
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  • News & Highlights | JILA-PFC
    i e crystal of light to generate the ticks of its clock The Sr lattice clock can precisely control the quantum states of read more Mission Control Published 01 14 2014 Capturing and controlling the fleeting dance of electrons as they rearrange during a chemical reaction has been a long standing challenge in science for several decades Since electrons are much lighter than atoms they can respond almost instantaneously on time scales of hundreds of attoseconds where an attosecond is 10 18 s Fortunately over the last decade scientists have created attosecond x ray strobe lights that are fast enough to freeze the motion of electrons However simply read more Puff the Magic Atoms Published 01 13 2014 The Cornell and Jin groups have just met the challenge of creating and studying an extremely strongly interacting Bose Einstein condensate BEC This feat was reported in Nature Physics online January 12 2014 An example of an ordinary weakly interacting Bose Einstein condensate BEC is a quantum gas of rubidium atoms 85Rb all piled up in a little ball whose temperature is a chilly 10 nK Normally the interactions between these atoms are weak and the atoms behave as if they were much read more The Dipolar Express Published 12 06 2013 Physicists wonder about some pretty strange things For instance one burning question is How round is the electron While the simplest picture of the electron is a perfect sphere it is possible that it is instead shaped like an egg The egg shape would look a bit like a tiny separation of positive and negative charges Physicists call this kind of charge separation an electric dipole moment or EDM The existence of an EDM in the electron or any other subatomic particle will have a profound read more The Squeeze Machine Published 10 11 2013 Research associate Tom Purdy and his colleagues in the Regal group have just built an even better miniature light powered machine that can now strip away noise from a laser beam Their secret a creative workaround of a quantum limit imposed by the Heisenberg Uncertainty Principle This limit makes it impossible to simultaneously reduce the noise on both the amplitude and phase of light inside interferometers and other high tech instruments that detect miniscule position changes Purdy s team read more The Great Spin Swap Published 09 18 2013 Research associate Bo Yan and his colleagues recently observed spin exchanges in ultracold potassium rubidium KRb molecules inside an optical lattice a crystal of light formed by interacting laser beams In solid materials such spin exchanges are the building blocks of advanced materials and exotic behavior The spin exchanges occurred when a rotationally excited KRb molecule interacted with a non rotating KRb molecule in the ground state Amazingly the two molecules could be relatively read more The Magnificent Quantum Laboratory Published 08 08 2013 Because quantum mechanics is crucial to understanding the behavior of everything in the Universe one can understand key elements of the behavior

    Original URL path: http://jila-pfc.colorado.edu/news/news-highlights?page=1 (2016-04-29)
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  • News & Highlights | JILA-PFC
    of the particles its linked partners will also respond However entangled quantum states are notoriously fragile This fragility is an inherent part of their nature Even so a recent read more Schrödinger Cats Light the Way Published 01 13 2012 We can get valuable information about a material by studying how it responds to light But up to now researchers have been forced to ignore how some of light s stranger quantum behavior such as being in a superposition of one or more intensity states affects these measurements New research from the Cundiff group with newly minted PhD Ryan Smith and graduate student Andy Hunter has shown that it is possible to back calculate how a semiconductor responds to light s quantum features even read more Quantum Body Swapping Published 10 28 2011 There s something happenin here what it is ain t exactly clear Buffalo Springfield Theorists Norio Takemoto now at the Weizmann Institute of Science and Fellow Andreas Becker figured that something was amiss when they first analyzed the details of what occurs when an ultrafast laser dislodges an electron from a simple molecular ion H2 Since H2 has already lost one of its electrons its two protons only have one electron left to play with How hard would it be to see what read more Cross Cultural Spectroscopy Published 10 19 2011 Graduate student Jennifer Lubbeck Jimenez Group spent the summer of 2011 doing research in the Molecular Spectroscopy Laboratory at the RIKEN Institute in Wako Japan near Tokyo Her host s group included 16 postdocs and four graduate students Figure 1 The group was under the direction of Chief Scientist Tahei Tahara However Lubbeck actually worked directly with just five other young scientists under the supervision of Professor Kunihiko Ishi Ishi san I was able to learn ultrafast read more Chemistry in the Cosmos Published 10 19 2011 Searching for Clues in Quantum Fingerprints The Nesbitt group wants to figure out how chemistry works in outer space In particular the group wants to understand the cosmo chemistry leading to the generation of soot which is similar to products of combustion here on Earth Outer space is full of molecules Nesbitt explains We want to discover how these molecules are formed out there He adds that radio telescopes have gathered evidence of molecules made of long chains of carbon atoms read more Ultracold Polar Molecules to the Rescue Published 09 14 2011 Physicists would very much like to understand the physics underlying high temperature superconductors Such an understanding may lead to the design of room temperature superconductors for use in highly efficient and much lower cost transmission networks for electricity A technological breakthrough like this would drastically reduce world energy costs However this breakthrough requires a detailed understanding of the physics of high temperature superconductivity There is already a read more The Cold Case Published 09 02 2011 The Ye group has built a cool new system for studying cold collisions between molecules The system is far

    Original URL path: http://jila-pfc.colorado.edu/news/news-highlights?page=2 (2016-04-29)
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  • News & Highlights | JILA-PFC
    Summer 2008 Near the crossover point the physics of superfl uidity in an atom gas system may be connected to that of high temperature superconductivity In the 2008 experiment read more An Occurence at the Solvent Bridge Published 08 18 2010 Solvents don t just dissolve other chemicals called solutes and then sit around with their hands in their pockets Instead they get involved in all sorts of different ways when dissolved molecules toss electrons around i e they facilitate charge transfer events In research the hard part is fi guring out exactly how and when solvent molecules get involved when an electron hops from one solute molecule to another For example in liquids which do most of the dissolving solvent read more Them s the Brakes Published 08 18 2010 The Bohn group has just come up with an exciting really complicated experiment for someone else to do This is something theorists like graduate student Ryan Wilson former research associate Shai Ronen and Fellow John Bohn get a kick out of In this case they re recommending an experiment to measure how fast a tiny blue laser would have to move through a dipolar Bose Einstein condensate BEC to create ripples Energy lost to the ripples would create a drag force on the laser signaling the read more Redefining Chemistry at JILA Published 05 06 2010 Fellows Deborah Jin Jun Ye and John Bohn are exploring new scientific territory in cold molecule chemistry Experimentalists Jin and Ye and their colleagues can now manipulate observe and control ultralow temperature potassium rubidium KRb molecules in their lowest quantum mechanical state Theorist Bohn analyzes what the experimentalists see and predicts molecule behaviors under different conditions No other group in the world has even succeeded in making molecules like these much read more Freeze Frame Published 04 17 2010 The cold molecule collaboration has developed a method for directly imaging ultracold ground state KRb molecules Their old method required the transfer of ultracold KRb molecules into a Feshbach state which is sensitive to electric and magnetic fields Thus researchers had to turn off the electric field and keep the magnetic field at a fixed value during the imaging process However the team recently began to probe the influence of changing electric and magnetic fields on the behavior of read more Good Vibrations Published 04 03 2010 Mathias Weber and his team recently did the following experiment They excited the methyl group CH3 on one end of nitromethane anion CH3NO2 with an infrared IR laser The laser got the methyl group vibrating with enough energy to get the nitro group NO2 at the other end of the molecule wagging hard enough to spit out its extra electron The figure here which appeared on the April 1 2010 cover of the Journal of Physical Chemistry A shows an artist s conception of the process from read more The BEC Transporter Published 04 02 2010 The Dana Z Anderson group has developed a microchip based system

    Original URL path: http://jila-pfc.colorado.edu/news/news-highlights?page=3 (2016-04-29)
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