Ana Maria Rey

Rey

kdcadmin — Thu, 23 Mar 2023 18:24:18 +0000

Ana Maria Rey

Affiliations

Fellow of CTQM
Fellow of JILA
Adjoint Professor, Department of Physics, University of Colorado Boulder

Bio

My main research interest is ultracold atoms and molecules loaded in optical lattices, which are periodic trapping potentials created by illuminating the atoms and molecules with laser beams. Atoms in optical lattices are analogous to electrons in solid state crystals. Their big advantage is that these "artificial crystals of light" are perfectly clean and highly controllable. Therefore, they are ideal for exploring a whole range of fundamental phenomena that are extremely difficult — or impossible — to study in traditional condensed matter systems. My goal is to study how to control and manipulate these systems to engineer different quantum phases such as superfluids, insulators, quantum magnets, and topological matter. I plan to use them for understanding the physics of strongly correlated bosonic and fermionic systems and nonequilibrium phenomena. Additionally, I am interested in studying how to generate and manipulate entanglement in quantum systems for use in quantum information processing and precision measurements.

CTQM Role

CTQM Fellow

Research Category

atomic, molecular, and optical physics

quantum information science

arey@jilau1.colorado.edu

Phone

303-492-8089 (office)

Website

https://jila.colorado.edu/arey

Quantum Information Science

kdcadmin — Thu, 09 Mar 2023 21:44:35 +0000

Quantum Information Science kdcadmin Thu, 03/09/2023 - 2:44 pm

A fundamental assumption of quantum information science is that there are degrees of freedom in quantum matter with long-lived coherence suitable for realizing controllable quantum bits--the fundamental information units of quantum information and computation. The existence of such degrees of freedom and the irreducibly quantum features of their states reveals fundamental features of the underlying physics. Thus, quantum information provides a framework for investigating the control and measurement of quantum matter and provides new insights into its states and phases.

Work at the CTQM involving quantum information includes the theory needed to control and characterize trapped ion and atom systems, the use of these systems for ``digital'' and ``analog'' simulations of models of quantum matter beyond the ability of classical simulations, the study of fundamentally quantum correlations and their role in phases of quantum matter, and investigations of the requirements for and properties of emergent and engineered quantum subsystems.

CTQM Fellow(s)

Atomic, Molecular, and Optical Physics

kdcadmin — Thu, 09 Mar 2023 21:38:45 +0000

Atomic, Molecular, and Optical Physics kdcadmin Thu, 03/09/2023 - 2:38 pm

Atomic, molecular and optical physics research interests are on developing ways to dynamically manipulate, control and understand interacting atomic molecular and optical systems. The main goals are to use them as quantum simulators of solid state materials and high energy systems, as quantum information processors, and to engineer improved quantum devices and technologies such as ultra-precise atomic clocks and quantum sensors. Topics at the top of our research priorities are: orbital quantum magnetism, quantum metrology with many-body states, topological quantum matter and non-equilibrium open driven quantum systems.

CTQM Fellow(s)

Ana Maria Rey

Murray Holland

Exciting Adventures in Coupling

kdcadmin — Fri, 26 Sep 2014 17:31:27 +0000

Exciting Adventures in Coupling kdcadmin Fri, 09/26/2014 - 11:31 am

According to new theory by the Gurarie and Rey groups, dipole-dipole interactions between ultracold polar molecules pinned in an optical lattice can make the molecules swap their internal rotational state (spin) at the cost of inducing a net spin current across the lattice. This elaborate spin swapping, which affects molecule motion or circulation, is known as spin-orbit coupling.

Image Credit

The Rey group and Steve Burrows

New theory describing the spin behavior of ultracold polar molecules is opening the door to explorations of exciting, new physics. According to the Gurarie and Rey theory groups, 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 CU Associate Research Professor of Physics Ana Maria Rey. Guarie and Rey are CTQM Fellows. 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, ultracold polar-molecule experiments are ideally suited for this purpose. For example, ultracold KRb molecules are polar, which means that the K end of one molecule attracts the Rb end of another molecule, while two K ends or two Rb ends repel each other. These behaviors are known as dipole-dipole interactions. The new theory predicts that dipole-dipole interactions will spontaneously give rise to spin-orbit coupling in an ultracold gas of polar molecules.

“The nice part is that with cold molecules, spin-orbit coupling just exists,” Rey explained. “We don’t need to zap anything with a laser to create it.”

Rey and her collaborators predict that spin-orbit coupling in ultracold polar molecules will generate excitations called chirons. Chirons are similar to the quasi particles found in bilayer graphene. They are expected to show up in the spin behaviors, spin currents, and spin interactions that occur in an ensemble of ultracold polar molecules pinned inside a deep optical lattice (a crystal of light created by intersecting laser beams). In other words, just about everything predicted by the new theory could soon be tested in the ultracold molecule laboratory in JILA!

Principal Investigators

Ana Maria Rey

Victor Gurarie

Research Topics

atomic, molecular, and optical physics

Atoms, Atoms, Frozen Tight in the Crystals of the Light, What Immortal Hand or Eye Could Frame Thy Fearful Symmetry?

kdcadmin — Mon, 18 Aug 2014 17:21:59 +0000

Atoms, Atoms, Frozen Tight in the Crystals of the Light, What Immortal Hand or Eye Could Frame Thy Fearful Symmetry? kdcadmin Mon, 08/18/2014 - 11:21 am

Strontium atoms in a quantum simulator display SU(N≤10) symmetry because of having 10 different nuclear spin states that are decoupled from their electronic and motional states. This symmetry was predicted by the Rey group and recently observed by the Ye group.

Image Credit

The Ye and Rey groups, and Steve Burrows

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 (⁸⁷Sr) 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 ⁸⁷Sr 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 ⁸⁷Sr atoms at cold and ultracold temperatures; (2) Exquisite measurement precision available from an ultrastable laser developed for the ⁸⁷Sr-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 ⁸⁷Sr atoms, whose 10 nuclear spin states are decoupled from their interparticle interactions; and (4) The experimental control of the number of ⁸⁷Sr 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 ⁸⁷Sr 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 spin liquid will form if ⁸⁷Sr atoms are prepared in all 10 nuclear spin states and cooled down in a two-dimensional lattice (crystal of light). This exotic substance has no apparent order even at ultralow temperatures approaching absolute zero!

The researchers responsible for launching this new, exciting work include research associate Xibo Zhang, graduate students Mike Bishof and Sarah Bromley, research associate Christina Krauss and Professor Peter Zoller of the University of Innsbruck (Austria), Professor Marianna Safronova of the University of Delaware as well as CU Associate Research Professor of Physics Ana Maria Rey and CU Professor of Physics Adjoint Jun Ye. Rey is a CTQM Fellow.

Principal Investigators

Ana Maria Rey

Research Topics

atomic, molecular, and optical physics

Dealing with Loss

kdcadmin — Wed, 05 Mar 2014 18:06:21 +0000

Dealing with Loss kdcadmin Wed, 03/05/2014 - 11:06 am

By continuously measuring ultracold KRb molecules in tubes (with weak lattices) created by intersecting laser beams, researchers suppress the loss of the molecules during experiments. The loss suppression is due to the quantum Zeno effect.

Image Credit

The Ultracold Molecule Collaboration and Brad Baxley,

There’s exciting news from JILA’s ultracold molecule collaboration. The Jin, Ye, Holland, and Rey groups have come up with new theory (verified by experiment) that explains the suppression of chemical reactions between potassium-rubidium (KRb) molecules in the KRb quantum simulator. The main reason the molecules do not collide and react is continuous measurement of molecule loss from the simulator. That it works this way is a consequence of the quantum Zeno effect, also known as the watched pot effect, as in the proverb “A watched pot never boils.”

In essence, if researchers investigate a quantum system by continuously measuring it, things stop changing altogether. The strange laws of quantum mechanics are responsible for this odd behavior. These laws dictate that the act of measurement itself forces the KRb molecules into a particular quantum state. And, if measurements occur continuously, the molecules will stay in that state because the measurements themselves are collectively preventing any change in the quantum states of the molecules. The idea that continuous measurements prevent a quantum system from evolving is the essence of the quantum Zeno effect, named for the Greek philosopher Zeno of Elea.

Thus, if you adjust a quantum simulator so that (according to the laws of classical physics) the molecules inside it get lost faster and faster because of colliding and reacting, then the laws of quantum mechanics will actually make the molecules react slower and slower until they eventually just sit there forever and never get lost. It’s almost as if two KRb molecules “know” from the continuous measurements not to hop into the same place in the simulator because they would react and disappear if they did. New theory by the Holland and Rey groups shows explicitly how this works. It not only verifies the quantum Zeno effect, but also demonstrates that older theories that attempted to explain this kind of quantum behavior incorrectly predicted loss to happen five times faster.

In practical terms, the previous and less accurate theories suggested that the number of KRb molecules in the simulator would be about one molecule per two lattice sites (which are energy wells created by intersecting laser beams). In practice, however, that calculation predicted too many molecules. Right now, the number of KRb molecules in the simulator is fewer, typically one per every 10 lattice sites. And, this just happens to match the amount of lattice filling predicted by the new theory. Clearly, increasing the lattice filling is going be a lot harder than researchers originally expected it to be.

Untangling this complicated quantum behavior required the brainpower and dedication of 13 JILA researchers. The theory team comprised graduate student Bihui Zhu, recently minted Ph.D. Michael Foss-Feig, research associates Johannes Schachenmayer and Michael Wall, senior research associate Kaden Hazzard as well as CU Professor of Physics Murray Holland and CU Associate Research Professor of Physics Ana Maria Rey. Holland and Rey are CTQM Fellows. The experimental team included research associates Bryce Gadway and Bo Yan, graduate students Steven Moses and Jacob Covey, and Fellows Debbie Jin and Jun Ye.

Principal Investigators

Ana Maria Rey

Murray Holland

Research Topics

atomic, molecular, and optical physics

New Flavors of Quantum Magnetism

kdcadmin — Thu, 24 May 2012 17:18:45 +0000

New Flavors of Quantum Magnetism kdcadmin Thu, 05/24/2012 - 11:18 am

Artist's conception of a 3-dimensional optical lattice.

Image Credit

The Rey Group and Brad Baxley

News Flash! The Rey group has discovered another good reason for using alkaline-earth atoms, such as strontium (Sr) or Ytterbium (Yb), in experimental quantum simulators. Quantum simulators are systems that mimic interesting materials or mathematical models in a very controlled way. The new reason for using alkaline earth atoms in such systems comes from the fact that their nuclei come in as many as 10 different magnetic flavors, i.e., their spins can be in 10 different quantum states.

When people normally think about magnetism, they often think of the two most common magnetic flavors: spin up and spin down. And, when the spins of billions and billions of iron atoms all line up in one of these two directions, the result is the familiar bar magnet.

But things are never so simple and straightforward in the quantum world. It’s as if in addition to spin up and spin down in alkaline earth atoms, there were also eight more unique spin directions such as spin forwards, spin backwards, or spin diagonal. (Of course, in this case, the spin directions are just a convenient analogy for quantum spin states.)

The multi-flavored alkaline earth atoms have some real advantages in quantum simulation. Inside a simulator, a set number of alkaline-earth atoms with ten flavors can actually make the whole system get five times colder than the same number of atoms with only two flavors. This result was entirely unexpected.

Conventional wisdom said that a higher number of magnetic flavors in the atomic nuclei would cause the lowest-possible temperature of the system to be higher than that of a system with a lower number of magnetic flavors!

“I was so shocked when we first saw this, I spent a whole day trying to find the error in my calculation,” said Kaden Hazzard, an NRC (National Research Council) postdoc with the Rey group. But, Hazzard hadn’t made a mistake. The Rey group has proved conventional wisdom wrong — and opened the door to some novel experiments with the quantum simulator in the Ye lab.

Since the simulator is already kept at ultracold temperatures, the newly discovered relationship of cooling to an increased number of spin states means that it should theoretically be possible to cool highly controlled atoms down to nano-Kelvin temperatures. Such temperatures are needed to directly observe quantum magnetism in action.

“When you get alkaline earth atoms really cold, that’s when you can see the most interesting physics,” Hazzard said.

Because of the unique properties of alkaline earth atoms, scientists will soon be able to study what happens when different magnetic flavors interact and produce spin ordering. For instance, as a simulator gets colder, random flavors may take on their preferred spin direction at regular intervals inside a three-dimensional lattice, like the one shown in the figure.

This behavior will set the stage for the creation of antiferromagnets and spin liquids. In antiferromagnets, random magnetic flavors assume their preferred directions at utralow temperatures of below 1 nK. Spin liquids can occur when interactions or geometrical factors frustrate the antiferromagnetic order, causing it to “ melt.” In the resulting spin liquid, spins can fluctuate through different states even near a temperature of absolute zero.

Antiferromagnets and spin liquids have not yet been observed in the laboratory. But, the Rey group’s predictions give hope that they soon may be seen soon in simulators using alkaline earth atoms.

The work on the new flavors of quantum magnetism was done by Hazzard, CU Associate Research Professor of Physics Ana Maria Rey, CU Associate Professor of Physics Victor Gurarie and CU Professor of Physics Michael Hermele. Rey, Guarie, and Hermele are also CTQM Fellows. Research associates Salvatore Manmana and Gang Chen as well as colleague Adrian Feiguin of the University of Wyoming worked with Hazzard and Rey on foundational work for the new theory. The Rey group is continuing its investigations of quantum magnetism with colleagues in Germany and Austria.

Principal Investigators

Ana Maria Rey

Michael Hermele

Research Topics

quantum information science