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### Special Particle, Astrophysics, and Nuclear Physics Seminar

Monday, February 6th, 201702:00 PM - 03:00 PM

Storrs Campus

Physics Building, P121

Dr. Luchang Jin,

Brookhaven National Laboratory

The hadronic light-by-light contribution to muon g-2 from lattice QCD

The current measurement of muonic g-2 disagrees with the theoretical

calculation by about 3 standard deviations. Hadronic vacuum

polarization (HVP) and hadronic light by light (HLbL) are the two

types of processes that contribute most to the theoretical

uncertainty. The current value for HLbL is still given by models. We

report our latest lattice calculation of hadronic light-by-light

contribution to muon g-2 using our recent developed moment method. The

connected diagrams and the leading disconnected diagrams are included.

The calculation is performed on a 48^3 × 96 lattice with physical pion

mass and 5.5 fm box size. We expect sizable finite volume and finite

lattice spacing corrections to the results of these calculations which

will be estimated in calculations to be carried out over the next 1-2

years.

Brookhaven National Laboratory

The hadronic light-by-light contribution to muon g-2 from lattice QCD

The current measurement of muonic g-2 disagrees with the theoretical

calculation by about 3 standard deviations. Hadronic vacuum

polarization (HVP) and hadronic light by light (HLbL) are the two

types of processes that contribute most to the theoretical

uncertainty. The current value for HLbL is still given by models. We

report our latest lattice calculation of hadronic light-by-light

contribution to muon g-2 using our recent developed moment method. The

connected diagrams and the leading disconnected diagrams are included.

The calculation is performed on a 48^3 × 96 lattice with physical pion

mass and 5.5 fm box size. We expect sizable finite volume and finite

lattice spacing corrections to the results of these calculations which

will be estimated in calculations to be carried out over the next 1-2

years.

Contact Information: Gerald V. Dunne
More

### Cancelled: Special PAN Seminar

Thursday, February 9th, 201702:00 PM - 03:00 PM

Storrs Campus

Physics Building, P121

Dr. Duff Neill,

Los Alamos National Laboratory

The Substructure of Jets

The field of jet substructure has rapidly developed over the last few

years in order to maximize the use of the data recorded at the Large

Hadron Collider. This has forced QCD theorists to think hard about the

structure of the QCD cascade to find observables which can

discriminate between hadronically decaying color singlet states from

the QCD background. After giving an introduction to Soft-Collinear

Effective Field Theory and the ideas behind factorization theorems, I

will explain how effective field theory and the use of power counting

gives an intuitive way to organize the phase space for the QCD

cascade. The mode decomposition and power counting of the EFT breaks

up the phase-space into regions where one can use factorization

theorems to resum the perturbation series for both signal and

background distributions, leading to reliable predictions for

discrimination. Beyond their phenomenological utility, such

substructure factorization theorems can in turn be used to illuminate

the formal structure of the perturbation series for more inclusive

observables, allowing one to demonstrate emergent phenomena in jet

dynamics. Such phenomena is not captured when using standard

fixed-order perturbation theory, leading to a finite radius of

convergence for even the leading logarithmic series.

Los Alamos National Laboratory

The Substructure of Jets

The field of jet substructure has rapidly developed over the last few

years in order to maximize the use of the data recorded at the Large

Hadron Collider. This has forced QCD theorists to think hard about the

structure of the QCD cascade to find observables which can

discriminate between hadronically decaying color singlet states from

the QCD background. After giving an introduction to Soft-Collinear

Effective Field Theory and the ideas behind factorization theorems, I

will explain how effective field theory and the use of power counting

gives an intuitive way to organize the phase space for the QCD

cascade. The mode decomposition and power counting of the EFT breaks

up the phase-space into regions where one can use factorization

theorems to resum the perturbation series for both signal and

background distributions, leading to reliable predictions for

discrimination. Beyond their phenomenological utility, such

substructure factorization theorems can in turn be used to illuminate

the formal structure of the perturbation series for more inclusive

observables, allowing one to demonstrate emergent phenomena in jet

dynamics. Such phenomena is not captured when using standard

fixed-order perturbation theory, leading to a finite radius of

convergence for even the leading logarithmic series.

Contact Information: Prof. Gerald Dunne
More

### Atomic, Molecular, and Optical Physics Seminar

Friday, February 10th, 201710:00 AM - 11:00 AM

Storrs Campus

Gant Plaza, IMS159

Dr. Daniel McCarron,

Yale University

Laser cooling and trapping of diatomic molecules:

New tools for quantum science and precision measurements

Laser cooling and trapping have revolutionized atomic physics, enabling a huge range of advances in science and technology, from Bose-Einstein condensates and matter-wave interferometry to improved atomic clocks. In recent years, it has become clear that general methods to produce ultracold molecules would have a similarly broad scientific impact. Compared to atoms, the rich internal structures of molecules make them highly versatile tools to advance our understanding of complex quantum systems with interactions, to produce new quantum technologies, to control quantum effects in chemical reactions, and to realize improved precision measurements.

However, despite intense interest, methods for cooling and trapping molecules have developed far more slowly than their atomic counterparts. In particular, direct laser cooling of molecules was long considered infeasible; the same rich internal structure that makes molecules useful for a wide range of applications also poses challenges once believed to be fatal to any attempt at laser cooling. Over the past several years, however, our group and others have devised and implemented methods to overcome these difficulties. Our group has demonstrated that the standard tools of atomic laser cooling—including Doppler and sub-Doppler cooling, beam slowing, and (most recently) magneto-optical trapping—can work with molecules, in a manner very similar to the familiar cases for atoms. In this talk, I will review progress in laser cooling and trapping of molecules, and give an outlook for future directions enabled by these rapidly-developing methods.

Yale University

Laser cooling and trapping of diatomic molecules:

New tools for quantum science and precision measurements

Laser cooling and trapping have revolutionized atomic physics, enabling a huge range of advances in science and technology, from Bose-Einstein condensates and matter-wave interferometry to improved atomic clocks. In recent years, it has become clear that general methods to produce ultracold molecules would have a similarly broad scientific impact. Compared to atoms, the rich internal structures of molecules make them highly versatile tools to advance our understanding of complex quantum systems with interactions, to produce new quantum technologies, to control quantum effects in chemical reactions, and to realize improved precision measurements.

However, despite intense interest, methods for cooling and trapping molecules have developed far more slowly than their atomic counterparts. In particular, direct laser cooling of molecules was long considered infeasible; the same rich internal structure that makes molecules useful for a wide range of applications also poses challenges once believed to be fatal to any attempt at laser cooling. Over the past several years, however, our group and others have devised and implemented methods to overcome these difficulties. Our group has demonstrated that the standard tools of atomic laser cooling—including Doppler and sub-Doppler cooling, beam slowing, and (most recently) magneto-optical trapping—can work with molecules, in a manner very similar to the familiar cases for atoms. In this talk, I will review progress in laser cooling and trapping of molecules, and give an outlook for future directions enabled by these rapidly-developing methods.

Contact Information: Prof. Phillip Gould
More

### Special Particle, Astrophysics, and Nuclear Physics Seminar

Friday, February 10th, 201702:00 PM - 03:00 PM

Storrs Campus

Physics Building, P121

Los Alamos National Laboratory

The Substructure of Jets

The field of jet substructure has rapidly developed over the last few

years in order to maximize the use of the data recorded at the Large

Hadron Collider. This has forced QCD theorists to think hard about the

structure of the QCD cascade to find observables which can

discriminate between hadronically decaying color singlet states from

the QCD background. After giving an introduction to Soft-Collinear

Effective Field Theory and the ideas behind factorization theorems, I

will explain how effective field theory and the use of power counting

gives an intuitive way to organize the phase space for the QCD

cascade. The mode decomposition and power counting of the EFT breaks

up the phase-space into regions where one can use factorization

theorems to resum the perturbation series for both signal and

background distributions, leading to reliable predictions for

discrimination. Beyond their phenomenological utility, such

substructure factorization theorems can in turn be used to illuminate

the formal structure of the perturbation series for more inclusive

observables, allowing one to demonstrate emergent phenomena in jet

dynamics. Such phenomena is not captured when using standard

fixed-order perturbation theory, leading to a finite radius of

convergence for even the leading logarithmic series.

Contact Information: Gerald V. Dunne
More

### Special Particle, Astrophysics, and Nuclear Physics Seminar

Monday, February 13th, 201702:00 PM - 03:00 PM

Storrs Campus

Physics Building, P121

Dr. Vladimir Skokov, Brookhaven National Laboratory

Probing Quantum Chromodynamics with long-range correlations in high energy collisions

Experiments with high-energy heavy-ion collisions recreate extreme conditions of the Early Universe microseconds after the Big Bang. These collisions also provide a unique opportunity to study the phase diagram of Quantum Chromodynamics, the only phase diagram of the Standard model that we can map both experimentally and theoretically. Recent measurements at RHIC suggest the presence of a critical point and first-order phase transition in the QCD phase diagram; however, in order to provide compelling evidence it is necessary to have a thorough theoretical understanding of the time evolution. Late-time evolution can be directly probed in an experiment and compared to theoretical models; however, it screens signals from the early stages. Looking beyond the horizon of the late stage is possible by investigating long-range correlations in rapidity. In this talk, I will focus on the first-principle description of the long-range correlations, specifically azimuthal anisotropy, and discuss our interpretation of some surprising aspects of the experimental data, in the framework of QCD in the non-linear regime.

Probing Quantum Chromodynamics with long-range correlations in high energy collisions

Experiments with high-energy heavy-ion collisions recreate extreme conditions of the Early Universe microseconds after the Big Bang. These collisions also provide a unique opportunity to study the phase diagram of Quantum Chromodynamics, the only phase diagram of the Standard model that we can map both experimentally and theoretically. Recent measurements at RHIC suggest the presence of a critical point and first-order phase transition in the QCD phase diagram; however, in order to provide compelling evidence it is necessary to have a thorough theoretical understanding of the time evolution. Late-time evolution can be directly probed in an experiment and compared to theoretical models; however, it screens signals from the early stages. Looking beyond the horizon of the late stage is possible by investigating long-range correlations in rapidity. In this talk, I will focus on the first-principle description of the long-range correlations, specifically azimuthal anisotropy, and discuss our interpretation of some surprising aspects of the experimental data, in the framework of QCD in the non-linear regime.

Contact Information: Prof. Gerald Dunne
More

### Atomic, Molecular, and Optical Physics Seminar

Tuesday, February 14th, 201711:00 AM - 12:00 PM

Storrs Campus

Gant Plaza, IMS159

Dr. Ryan Coffee,

SLAC National Accelerator Laboratory

Coherence pumping: using tailored modulations to synthesize multiple views of molecular dynamics

In chemical physics, experimental techniques are particularly well-tuned to specific observation channels. For

instance, valence chemical activity can be probed by uv/vis transient absorption spectroscopy. Site-specific dynamics

and coherent excitation can be observed via resonant Auger and photo- electron spectroscopy. Molecular structure, on

the other hand, is much more readily probed with hard x-ray or electron diffraction. In all cases, however, the same

physical mechanism unifies each of these representations of the underlying molecular dynamics. We use strong field

induced rovibrational coherences to merge experimentally disparate techniques as if performed in a single experiment.

Specifically, we use impulsive alignment in N2O to combine free-electron laser based soft x-ray spectroscopy (LCLS)

together with ultrafast electron diffraction (UED). Coherent alignment reveals the body-frame symmetry of resonant

Auger electron spectral features. It also reveals a subtle resonant effect called Neighbor Atom Core Hole Transfer,

hitherto only observed in multi-particle coincidence. Not only do we lift the need for coincidence detection, we also

free ourselves of the axial recoil approximation and thus enable scaling the method to larger and more complicated

molecular systems. By using the natural frequencies of the molecule for this variant of modulation spectroscopy, we

show how independent labs can merge their results with those of user facilities. Be it molecular structure, x-ray

spectra, uv/vis spectra, or fragmentation dynamics, such multi-channel results more heavily restrict theoretical

models since all results must hold mutual consistency. A picture may be worth a thousand words, but a stereographic

movie is worth much, much more.

SLAC National Accelerator Laboratory

Coherence pumping: using tailored modulations to synthesize multiple views of molecular dynamics

In chemical physics, experimental techniques are particularly well-tuned to specific observation channels. For

instance, valence chemical activity can be probed by uv/vis transient absorption spectroscopy. Site-specific dynamics

and coherent excitation can be observed via resonant Auger and photo- electron spectroscopy. Molecular structure, on

the other hand, is much more readily probed with hard x-ray or electron diffraction. In all cases, however, the same

physical mechanism unifies each of these representations of the underlying molecular dynamics. We use strong field

induced rovibrational coherences to merge experimentally disparate techniques as if performed in a single experiment.

Specifically, we use impulsive alignment in N2O to combine free-electron laser based soft x-ray spectroscopy (LCLS)

together with ultrafast electron diffraction (UED). Coherent alignment reveals the body-frame symmetry of resonant

Auger electron spectral features. It also reveals a subtle resonant effect called Neighbor Atom Core Hole Transfer,

hitherto only observed in multi-particle coincidence. Not only do we lift the need for coincidence detection, we also

free ourselves of the axial recoil approximation and thus enable scaling the method to larger and more complicated

molecular systems. By using the natural frequencies of the molecule for this variant of modulation spectroscopy, we

show how independent labs can merge their results with those of user facilities. Be it molecular structure, x-ray

spectra, uv/vis spectra, or fragmentation dynamics, such multi-channel results more heavily restrict theoretical

models since all results must hold mutual consistency. A picture may be worth a thousand words, but a stereographic

movie is worth much, much more.

Contact Information: Prof. George Gibson
More

### Atomic, Molecular, and Optical Physics Seminar

Thursday, February 16th, 201711:00 AM - 12:00 PM

Storrs Campus

Gant Plasa, IMS-159

Dr. Travis Nicholson,

MIT/Harvard Center for Ultracold Atoms

Nonlinear Quantum Optics with Symmetry Protection

Realizing robust quantum phenomena in strongly interacting systems is one of the central challenges in modern physical science. Approaches ranging from topological protection to quantum error correction are currently being explored across many different experimental platforms, including electrons in condensed-matter systems, trapped atoms, and photons. Although photon–photon interactions are negligible in conventional optical media, we have engineered a system based on electromagnetically induced transparency and Rydberg states that realizes strong photonic interactions. Recently, we have learned that if the Rydberg state coupling is primarily dipolar, our system undergoes a coherent state exchange process that is accompanied by a large, robust phase shift. The phase shift is robust because it originates from the symmetry of the interaction rather than precise experimental parameters. Since interaction-induced phase shifts are needed for photonic quantum logic, our "symmetry protected" process opens a route to realizing all-optical quantum gates.

MIT/Harvard Center for Ultracold Atoms

Nonlinear Quantum Optics with Symmetry Protection

Realizing robust quantum phenomena in strongly interacting systems is one of the central challenges in modern physical science. Approaches ranging from topological protection to quantum error correction are currently being explored across many different experimental platforms, including electrons in condensed-matter systems, trapped atoms, and photons. Although photon–photon interactions are negligible in conventional optical media, we have engineered a system based on electromagnetically induced transparency and Rydberg states that realizes strong photonic interactions. Recently, we have learned that if the Rydberg state coupling is primarily dipolar, our system undergoes a coherent state exchange process that is accompanied by a large, robust phase shift. The phase shift is robust because it originates from the symmetry of the interaction rather than precise experimental parameters. Since interaction-induced phase shifts are needed for photonic quantum logic, our "symmetry protected" process opens a route to realizing all-optical quantum gates.

Contact Information: Prof. P. Gould
More

### Special Particles, Astrophysics and Nuclear Physics Seminar

Thursday, February 16th, 201702:00 PM - 03:00 PM

Storrs Campus

Physics Building, P121

Dr. M. Hansen, Helmholtz Institute Mainz, University of Mainz

Extracting scattering observables and resonance properties from lattice QCD

QCD, the quantum theory of the strong force, gives rise to a rich variety of short-lived resonance states. Understanding these in detail is of great interest, both for predicting backgrounds in new-physics searches and for gaining general insight into strong-force dynamics and phenomenology. The numerical technique of lattice QCD (LQCD), which has proven very successful in studying the properties stable hadrons, should also play an important role in reaching a comprehensive, quantitative picture for states that decay via the strong force. In this talk, I will review methods for calculating resonance properties in LQCD with a particular focus on three-particle decay channels. I will explain how the restriction to a finite volume can used as a tool, rather than an unwanted artifact. In addition, I will highlight the future steps required for achieving rigorous LQCD calculations of excited nucleon and exotic meson states.

Extracting scattering observables and resonance properties from lattice QCD

QCD, the quantum theory of the strong force, gives rise to a rich variety of short-lived resonance states. Understanding these in detail is of great interest, both for predicting backgrounds in new-physics searches and for gaining general insight into strong-force dynamics and phenomenology. The numerical technique of lattice QCD (LQCD), which has proven very successful in studying the properties stable hadrons, should also play an important role in reaching a comprehensive, quantitative picture for states that decay via the strong force. In this talk, I will review methods for calculating resonance properties in LQCD with a particular focus on three-particle decay channels. I will explain how the restriction to a finite volume can used as a tool, rather than an unwanted artifact. In addition, I will highlight the future steps required for achieving rigorous LQCD calculations of excited nucleon and exotic meson states.

Contact Information: Prof. Gerald Dunne
More

### Special Particles, Astrophysics and Nuclear Physics Seminar

Monday, February 20th, 201702:00 PM - 03:00 PM

Storrs Campus

Physics Building, P121

Dr. Raul Briceno, Jefferson Laboratory

The exotic frontiers of nuclear physics

The non-perturbative nature of quantum chromodynamics (QCD) has historically left a gap in our understanding

of the connection between the fundamental theory of the strong interactions and the rich structure of experimentally

observed phenomena. For the simplest properties of stable hadrons, this is now circumvented by utilizing lattice QCD

(LQCD). In this talk I discuss a path that will allow us to access a variety of previously unexplored sectors of QCD.

As a proof of principle, I will focus my attention to the isoscalar-scalar sector of QCD. Carrying the quantum numbers

of the vacuum, this is perhaps one the most interesting channels of nuclear physics. Beyond playing a crucial role in

a range of phenomenologically important processes, it hosts some some of the most intriguing states of QCD. For

example, glueballs, which have long been upheld as a smoking gun of the low-energy validity of QCD, are expected to

appear in this channel. I restrict my attention to low energies and discuss the manifestation of the lightest of all

hadronic resonances, the sigma/f0(500), in QCD.

The exotic frontiers of nuclear physics

The non-perturbative nature of quantum chromodynamics (QCD) has historically left a gap in our understanding

of the connection between the fundamental theory of the strong interactions and the rich structure of experimentally

observed phenomena. For the simplest properties of stable hadrons, this is now circumvented by utilizing lattice QCD

(LQCD). In this talk I discuss a path that will allow us to access a variety of previously unexplored sectors of QCD.

As a proof of principle, I will focus my attention to the isoscalar-scalar sector of QCD. Carrying the quantum numbers

of the vacuum, this is perhaps one the most interesting channels of nuclear physics. Beyond playing a crucial role in

a range of phenomenologically important processes, it hosts some some of the most intriguing states of QCD. For

example, glueballs, which have long been upheld as a smoking gun of the low-energy validity of QCD, are expected to

appear in this channel. I restrict my attention to low energies and discuss the manifestation of the lightest of all

hadronic resonances, the sigma/f0(500), in QCD.

Contact Information: Prof. Gerald Dunne
More

### Atomic, Molecular, and Optical Physics Seminar

Monday, February 20th, 201704:00 PM - 05:00 PM

Storrs Campus

Physics Building, P121

Dr. Huanqian Loh, Department of Physics, MIT

Quantum Control of Ultracold Dipolar Molecules

Polar molecules offer long-range anisotropic interactions, which are fundamental to a wide variety of phenomena, from ferrofluid behavior to the folding of proteins. Recent demonstrations of cooling and trapping polar molecules have made it possible to study these particles in the quantum regime, making them highly attractive for applications such as quantum information storage and exploring novel condensed matter phases. In this talk, I will report on the quantum control of dipolar fermionic NaK molecules, which we have synthesized in the ground state at ultracold temperatures as low as 300 nK. Using microwaves, we have coherently manipulated not only the rotational states of the molecules, but also the nuclear spin degree of freedom. I will present our observation of nuclear spin coherence times on the scale of 1 second, and discuss its implications for quantum memory and probing new physics via Hertz-level precision spectroscopy.

Quantum Control of Ultracold Dipolar Molecules

Polar molecules offer long-range anisotropic interactions, which are fundamental to a wide variety of phenomena, from ferrofluid behavior to the folding of proteins. Recent demonstrations of cooling and trapping polar molecules have made it possible to study these particles in the quantum regime, making them highly attractive for applications such as quantum information storage and exploring novel condensed matter phases. In this talk, I will report on the quantum control of dipolar fermionic NaK molecules, which we have synthesized in the ground state at ultracold temperatures as low as 300 nK. Using microwaves, we have coherently manipulated not only the rotational states of the molecules, but also the nuclear spin degree of freedom. I will present our observation of nuclear spin coherence times on the scale of 1 second, and discuss its implications for quantum memory and probing new physics via Hertz-level precision spectroscopy.

Contact Information: Prof. P. Gould
More

### Atomic, Molecular, and Optical Physics Seminar

Thursday, February 23rd, 201702:00 PM - 03:00 PM

Storrs Campus

Physics Building, P121

Dr. Christian Schneider,

Physics and Astronomy Department,

UCLA

Quantum Control of Atoms, Ions, and Nuclei

Cold atoms and ions are exciting systems for a variety of measurements of

fundamental physics. Radio frequency traps open up experiments with both large

ensembles of ions, e.g. in cold chemistry, and experiments with few or single

ions, such as in quantum computation, optical clocks, and tests of fundamental

physics, where ultimate quantum control matters. Optical traps enable

complementary experiments with neutral atoms.

I will first describe recent results from our work on cold chemistry

and cold molecular ions using a hybrid atom--ion.

We have developed an integrated time-of-flight mass spectrometer, which allows

for the analysis of the complete ion ensemble with isotopic resolution.

With this new ability, we have significantly enhanced previous studies of cold

reactions and found unexpected, new reactions. Further, we demonstrated a

proof-of-principle implementation of non-equilibrium physics in our hybrid trap.

Current work aims at demonstrating rotational cooling of molecular ions.

Second, I will report our recent results in the search for the

nuclear isomeric transition in thorium-229. This transition in the

vacuum-ultraviolet regime (around 7.8 eV) eludes nuclear physics techniques

but becomes accessible to lasers. It is better isolated from the

environment than electronic transitions making it a very promising candidate for

future precision experiments, such as a nuclear clock and tests of fundamental

constants. Our approach employs a direct search with thorium-doped crystals.

In a first experiment with synchrotron radiation (ALS, LBNL), we were able to

exclude a large region of possible transition frequencies and lifetimes.

Currently, we continue our efforts with enhanced sensitivity using a pulsed VUV

laser system. Additionally, theoretical considerations of possible transition

energies and lifetimes will be presented.

Physics and Astronomy Department,

UCLA

Quantum Control of Atoms, Ions, and Nuclei

Cold atoms and ions are exciting systems for a variety of measurements of

fundamental physics. Radio frequency traps open up experiments with both large

ensembles of ions, e.g. in cold chemistry, and experiments with few or single

ions, such as in quantum computation, optical clocks, and tests of fundamental

physics, where ultimate quantum control matters. Optical traps enable

complementary experiments with neutral atoms.

I will first describe recent results from our work on cold chemistry

and cold molecular ions using a hybrid atom--ion.

We have developed an integrated time-of-flight mass spectrometer, which allows

for the analysis of the complete ion ensemble with isotopic resolution.

With this new ability, we have significantly enhanced previous studies of cold

reactions and found unexpected, new reactions. Further, we demonstrated a

proof-of-principle implementation of non-equilibrium physics in our hybrid trap.

Current work aims at demonstrating rotational cooling of molecular ions.

Second, I will report our recent results in the search for the

nuclear isomeric transition in thorium-229. This transition in the

vacuum-ultraviolet regime (around 7.8 eV) eludes nuclear physics techniques

but becomes accessible to lasers. It is better isolated from the

environment than electronic transitions making it a very promising candidate for

future precision experiments, such as a nuclear clock and tests of fundamental

constants. Our approach employs a direct search with thorium-doped crystals.

In a first experiment with synchrotron radiation (ALS, LBNL), we were able to

exclude a large region of possible transition frequencies and lifetimes.

Currently, we continue our efforts with enhanced sensitivity using a pulsed VUV

laser system. Additionally, theoretical considerations of possible transition

energies and lifetimes will be presented.

Contact Information: Prof. Phillip Gould
More

### Condensed Matter Physics Seminar

Thursday, February 23rd, 201702:00 PM - 03:00 PM

Storrs Campus

Gant Science Complex, IMS20

Ranga Dias,

Physics Department,

Harvard University

Pressing Hydrogen to Exotic Quantum States

At very high pressures delocalization of electrons provides a wealth of correlated electron phenomena: e.g.,

insulator-metal transitions, colossal magnetoresistance, valence fluctuations, heavy fermion behavior, non-Fermi

liquid behavior, superconductivity, magnetic order, quadrupolar order, etc. The occurrence of such a wide range of

correlated electron phenomena arises from a delicate interplay between competing interactions that can be tuned by

pressure, resulting in complex temperature T vs P phase diagrams. In this talk, I will discuss the application of

pressure on the simplest element in the universe—The “HYDROGENS”—to understand quantum effects and develop materials

with advanced properties.

Efforts to identify and develop new superconducting materials continue to increase rapidly. Solid metallic hydrogen,

the elusive phase of atomic hydrogen, is predicted to have exotic properties, such as room temperature

superconductivity, superfluidity (if it is a liquid), and metastability. It releases enormous energy if it returns to

the molecular phase (400kJ/mole: 35xTNT). After more than 80 years of tremendous theoretical progress and a legion of

experimental efforts, the most challenging conjecture in condensed matter science remained unproven until recently. I

shall present our most recent results on the solid hydrogens under pressure [1-3]. Finally, I shall discuss future

research directions in probing room temperature superconductivity.

1. Ranga P. Dias and Isaac F. Silvera, Accepted in Science (in press)

2. Ranga P. Dias, Ori Noked, and Isaac F. Silvera, Phys. Rev. Lett. 116, 145501 (2016)

3. Ranga P. Dias, Ori Noked, and Isaac F. Silvera, under review in Science (2017)

Physics Department,

Harvard University

Pressing Hydrogen to Exotic Quantum States

At very high pressures delocalization of electrons provides a wealth of correlated electron phenomena: e.g.,

insulator-metal transitions, colossal magnetoresistance, valence fluctuations, heavy fermion behavior, non-Fermi

liquid behavior, superconductivity, magnetic order, quadrupolar order, etc. The occurrence of such a wide range of

correlated electron phenomena arises from a delicate interplay between competing interactions that can be tuned by

pressure, resulting in complex temperature T vs P phase diagrams. In this talk, I will discuss the application of

pressure on the simplest element in the universe—The “HYDROGENS”—to understand quantum effects and develop materials

with advanced properties.

Efforts to identify and develop new superconducting materials continue to increase rapidly. Solid metallic hydrogen,

the elusive phase of atomic hydrogen, is predicted to have exotic properties, such as room temperature

superconductivity, superfluidity (if it is a liquid), and metastability. It releases enormous energy if it returns to

the molecular phase (400kJ/mole: 35xTNT). After more than 80 years of tremendous theoretical progress and a legion of

experimental efforts, the most challenging conjecture in condensed matter science remained unproven until recently. I

shall present our most recent results on the solid hydrogens under pressure [1-3]. Finally, I shall discuss future

research directions in probing room temperature superconductivity.

1. Ranga P. Dias and Isaac F. Silvera, Accepted in Science (in press)

2. Ranga P. Dias, Ori Noked, and Isaac F. Silvera, Phys. Rev. Lett. 116, 145501 (2016)

3. Ranga P. Dias, Ori Noked, and Isaac F. Silvera, under review in Science (2017)

Contact Information: Prof. J. Hancock
More

### Special Particle, Astrophysics, and Nuclear Physics Seminar

Monday, February 27th, 201702:00 PM - 03:00 PM

Storrs Campus

Physics Building, P121

Dr. Zohreh Davoudi, Center for Theoretical Physics, MIT

The Road to Nuclear Physics from Standard Model

At the core of nuclear physics is to understand complex phenomena occurring in the hottest and densest known environments in nature, and to unravel the mystery of the dark sector and other new physics possibilities. Nuclear physicists are expected to predict, with certainty, the reaction rates relevant to star evolutions and nuclear energy research, and to obtain the “standard” effects in nuclei to reveal information about the “non-standard” sector. To achieve such certainty, the field has gradually started to eliminate its reliance on the phenomenological models and has entered an era where the underlying interactions are "effectively" based on the Standard Model of particle physics, in particular Quantum Chromodynamics (QCD). The few-nucleon systems can now emerge directly from the constituent quark and gluon degrees of freedom and with only QCD interactions in play, using the numerical method of lattice QCD. Few-body observable, such as few-nucleon interactions and scattering amplitudes, as well transition amplitudes and reaction rates, have been the focus of this vastly growing field, as once obtained from QCD, and matched to effective field theories, can advance and improve the nuclear many-body calculations of exceedingly complex systems. This talk is a brief introduction to this program and its goals, with a great focus on the progress in few-body observables from QCD.

The Road to Nuclear Physics from Standard Model

At the core of nuclear physics is to understand complex phenomena occurring in the hottest and densest known environments in nature, and to unravel the mystery of the dark sector and other new physics possibilities. Nuclear physicists are expected to predict, with certainty, the reaction rates relevant to star evolutions and nuclear energy research, and to obtain the “standard” effects in nuclei to reveal information about the “non-standard” sector. To achieve such certainty, the field has gradually started to eliminate its reliance on the phenomenological models and has entered an era where the underlying interactions are "effectively" based on the Standard Model of particle physics, in particular Quantum Chromodynamics (QCD). The few-nucleon systems can now emerge directly from the constituent quark and gluon degrees of freedom and with only QCD interactions in play, using the numerical method of lattice QCD. Few-body observable, such as few-nucleon interactions and scattering amplitudes, as well transition amplitudes and reaction rates, have been the focus of this vastly growing field, as once obtained from QCD, and matched to effective field theories, can advance and improve the nuclear many-body calculations of exceedingly complex systems. This talk is a brief introduction to this program and its goals, with a great focus on the progress in few-body observables from QCD.

Contact Information: Prof. Gerald Dunne
More

### Atomic, Molecular, and Optical Physics Seminar

Monday, February 27th, 201704:00 PM - 05:00 PM

Storrs Campus

Physics Building, P121

Dr. Amelle Zair, Imperial College London

Atomic and Molecular Quantum-path interferences: towards the control of matter on an attosecond time scale

I will review how the discovery of quantum-path interferences has allowed us to experimentally reveal the quantum aspect of high harmonic generation in atoms and molecules. To illustrate this, I will present two prototypical results of the quantum path interferometry I obtained: In atom the quantum-path interferometry enable the access to the dipole phase acquired by the electronic wave packet during the high harmonic generation process [1]. In molecule, the quantum-path interferometry reveals femtosecond to attosecond dynamics occurring after ionisation of the target system [2].Then I will present routes and strategies I am implementing in order to reach not only the observation but also the in-situ control of electronic wave packets in atoms and molecules [3].

[1] Zair. A et al PHYSICAL REVIEW LETTERS 2008 Volume: 100 Issue: 14 Article Number: 143902

[2] Zair. A et al CHEMICAL PHYSICS 2013 Volume: 414 Pages: 184-191

[3] Zair. A EPSRC-CAF EP/J002348/1

Atomic and Molecular Quantum-path interferences: towards the control of matter on an attosecond time scale

I will review how the discovery of quantum-path interferences has allowed us to experimentally reveal the quantum aspect of high harmonic generation in atoms and molecules. To illustrate this, I will present two prototypical results of the quantum path interferometry I obtained: In atom the quantum-path interferometry enable the access to the dipole phase acquired by the electronic wave packet during the high harmonic generation process [1]. In molecule, the quantum-path interferometry reveals femtosecond to attosecond dynamics occurring after ionisation of the target system [2].Then I will present routes and strategies I am implementing in order to reach not only the observation but also the in-situ control of electronic wave packets in atoms and molecules [3].

[1] Zair. A et al PHYSICAL REVIEW LETTERS 2008 Volume: 100 Issue: 14 Article Number: 143902

[2] Zair. A et al CHEMICAL PHYSICS 2013 Volume: 414 Pages: 184-191

[3] Zair. A EPSRC-CAF EP/J002348/1

Contact Information: Prof. Phillip Gould
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### UConn Physics Colloquium

Friday, March 3rd, 201704:00 PM - 05:00 PM

Storrs Campus

Physics Building, Room PB-38

Prof. Kate Whitaker, University of Connecticut

Title and abstract forthcoming

Title and abstract forthcoming

Contact Information: Prof. A. Puckett
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