Deborah Jin

Introducing the Debbie Jin room and the Chiral Spiral

Steven Burrows — Fri, 10 Dec 2021 21:04:16 +0000

Introducing the Debbie Jin room and the Chiral Spiral Steven Burrows Fri, 12/10/2021 - 14:04

Kenna Hughes-Castleberry / JILA Science Communicator

Photo of Former JILA Fellow Deborah Jin

JILA Room S209 informally referred to as Affinity Room, has been renovated and now has an official name: the Debbie Jin Room. Named in honor of late JILA Fellow Debbie Jin, this suite of rooms is designed to foster and support community amongst JILA’s graduate students and postdocs. With games, books, colorful walls, and comfy couches, this room is multi-purpose and can be used for informal gatherings, meetings, activities, or as a place to get away and relax with your peers. The Debbie Jin Room is furnished with a meeting table, lounge area, and desk/workspace. Coffee and snacks are often present as well! All are welcome to use the Debbie Jin room and resources at any time. This room reflects the impact that Debbie Jin had on JILA and the scientific community, as she was a friend and mentor to her JILA colleagues, young scientists in training, and JILA staff members. Debbie was a role model and inspiration to all who knew her.

In order to officially introduce this room to JILA, there will be an open house on Thursday, January 27th from 3:30-5 pm in lieu of JILA snack time. This open house will host delicious food and a raffle for JILAns to win one of four $50 gift cards. Please join us if you can.

The JILA Welcome Lounge has also been officially renamed the Chiral Spiral. This name alludes to the famous spiral staircase at JILA’s entrance, as well as the physical phenomenon of chirality (mirror images) in molecules.

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It’s Triplets!

Steven Burrows — Thu, 05 Oct 2017 17:29:25 +0000

It’s Triplets! Steven Burrows Thu, 10/05/2017 - 11:29

Julie Phillips / Science Communicator

By quickly lowering the magnetic field in a Bose-Einstein condensate, Catherine Klauss and her colleagues in the Jin-Cornell group made a lot of two-atom molecules of rubidium (⁸⁵Rb₂). They also directly observed and identified‚ for the first time ever in an ultracold gas‚ about 8% of their molecules as Efimov molecules made of three rubidium atoms (⁸⁵Rb3). Image credit: Steven Burrows / JILA

Newly minted JILA Ph.D. Catherine Klauss and her colleagues in the Jin and Cornell group decided to see what would happen to a Bose-Einstein condensate of Rubidium-85 (⁸⁵Rb) atoms if they suddenly threw the whole experiment wildly out of equilibrium by quickly lowering the magnetic field through a Feshbach resonance.¹ Theoretically, this maneuver is predicted to make the atoms infinitely attracted to each other, and at the same time, infinitely repulsed by each other.

“This is a really crazy regime, and things happened really fast,” explained Klauss. “At this resonance, the energy of the atom pairs equaled the energy of molecules, and the interactions were going on like crazy.”

At first, Klauss and her colleagues thought they were losing most of the atoms in the experiment. However, they soon discovered the atoms were actually still there even though the researchers couldn’t see them any longer. The atoms had been transformed into molecules, which had to be probed differently.

Once the researchers realized they’d made molecules, they decided to study them. First, they held the molecules at a specific magnetic field and watched them decay away by turning back into atoms. But, no matter how many times they repeated the experiment, there was always a two-component decay: a fast one and a slower one. The slower decay varied with the density of the initial atom sample, which was expected for a two-atom molecule, or dimer (⁸⁵Rb₂).

But the initial decay was happening much too fast to involve dimers. After consulting with JILA theorist José D’Incao, Klauss and her colleagues concluded they were making three-atom molecules, or trimers. And, the trimers were almost certainly the Efimov molecules (⁸⁵Rb₃) that have been studied theoretically for nearly 50 years, including work by D’Incao over the past decade. In this experiment, about 8% of the ultracold ⁸⁵Rb atoms in the original BEC formed the exotic Efimov molecules.

“This is the first direct observation of Efimov molecules in an ultracold gas that we’ve already positively identified,” Klauss said. “You can tell these molecules apart from dimers because the Efimov trimers die faster. José’s theory predicted that Efimov trimers would have a lifetime of about 100 microseconds (10^-4 s), and that’s exactly what we see in the lab.”

The researchers responsible for discovering and investigating the 85Rb triplets included Klauss, graduate student Xin Xie, University of Colorado Boulder undergraduate student Carlos Lopez-Abadia, senior research associate José D’Incao, Fellows Deborah Jin and Eric Cornell as well as Zoran Hadzibabic of the University of Cambridge.––Julie Phillips

1. Near a Feshbach resonance, small changes in the magnetic field have dramatic effects on the interactions of atoms in an ultracold gas.

Newly minted JILA Ph.D. Catherine Klauss and her colleagues in the Jin and Cornell group decided to see what would happen to a Bose-Einstein condensate of Rubidium-85 (85Rb) atoms if they suddenly threw the whole experiment wildly out of equilibrium by quickly lowering the magnetic field through a Feshbach resonance.

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Deborah Jin Dies at 47

Steven Burrows — Mon, 19 Sep 2016 20:12:46 +0000

Deborah Jin Dies at 47 Steven Burrows Mon, 09/19/2016 - 14:12

Julie Phillips / Science Communicator

Deborah Jin passed away September 15, 2016, after a courageous battle with cancer. She was 47. Jin was an internationally renowned physicist and Fellow with the National Institute of Standards and Technology (NIST); Professor Adjunct in the Department of Physics at the University of Colorado Boulder, and a Fellow of JILA, a joint institute of NIST and the University of Colorado.

A bright light at JILA has gone dim much too soon. For more than two decades, Deborah Jin was a friend and mentor to her JILA colleagues, young scientists in training, and JILA staff members. She was a role model and inspiration for women scientists, and hopefully the future will bring more women like her into science. JILA is grieving her loss.

“Debbie was an incredible scientist, outstanding mentor, valued friend, and loving spouse and mother,” said Tom O’Brian, Quantum Physics Division Chief at JILA. “Her passing leaves a void at JILA, in the world-wide scientific community, and in the hearts of her family and friends that cannot be filled. Our deepest sympathies and thoughts are with Debbie’s family, and her friends and colleagues at JILA and across the world.”

Jin had many accomplishments and received much recognition for her work during an unusually productive career. She was a pioneer in polar molecule quantum chemistry. From 1995–1997, she worked with Eric Cornell and Carl Wieman at JILA on some of the earliest studies of dilute gas Bose-Einstein condensates, which form when particles known as bosons are cooled to just a few millionths of a degree above absolute zero (-459.67 °F). Since then she had continued to explore the physics of atomic gases at ultracold temperatures and investigates the link between superconductivity and Bose-Einstein condensation

Jin subsequently developed innovative technical systems to study the behavior of ultracold Fermi gases, whose atoms are particles known as fermions and can form a superfluid or Bose condensate, if they become correlated atom pairs. In 2003, her group made the first ultracold fermionic condensate, a new form of matter. Since 2004, her group has conducted detailed studies of the behavior of Fermi gases in the regime of strong interactions, or correlations.

In 2008, Jin collaborated with Fellow Jun Ye at JILA to create the first ultracold gas of polar molecules in the quantum regime. Using these ground-state potassium-rubidium (KRb) molecules, Jin and Ye began exploring ultracold chemistry in 2009. The team went on to use ultracold KRb molecules in a quantum simulator to investigate quantum behaviors.

"Debbie has forever changed my life with her friendship and scientific mind, and I am only one of many who were touched by her,” said Jun Ye. “No words can describe the deepest sense of void left by Debbie's passing. She was the best friend, the best colleague, and the best critic, all in one."

Dana Anderson, Chair of the JILA Institute, added "As a scholar and educator Debbie leaves behind an indelible legacy of achievement at the University."

In 2003, Jin received a MacArthur Fellowship (commonly known as a “genius grant”) from the John D. and Catherine T. MacArthur Foundation. In 2013, she was named the L’Oreal-UNESCO For Women in Science Laureate for North America. Her other prestigious awards include a 2002 Maria Goeppert Mayer Award, a 2004 Scientific American “Research Leader of the Year," a 2008 Benjamin Franklin Medal in Physics, a 2014 Institute of Physics Isaac Newton Medal, and the 2014 Comstock Prize in Physics. At the time of her election in 2005 and for several years afterward, Jin was the youngest member of the National Academy of Sciences.

“Deborah Jin was the definition of world-class faculty,” said ��Ҵ�ý�ƽ�� Chancellor Philip P. DiStefano. "The international scientific community has lost a giant, and our campus has lost a mentor to young scientists and an inspiration to female scientists. She will be deeply missed in many quarters. Our thoughts and prayers go out to her family."

Jin earned an A.B. in physics from Princeton in 1990 and a Ph.D. in physics from the University of Chicago in 1995. From 1995 to 1997, she was a National Research Council research associate at JILA, where she was hired in 1997 as a NIST physicist and assistant professor adjoint at the University of Colorado, Boulder.

Deborah Jin is survived by her husband, JILA Fellow John Bohn, their daughter Jackie Bohn, siblings Laural Jin O’Dowd and Craig Jin, and mother Shirley Jin.

Crist Mortuary is coordinating services for Debbie Jin. Information is available on the Crist website. In lieu of flowers, the family asks that donations be made in Debbie's name to either the Foundation for Women's Cancer or the World Wildlife Fund.

To share your remembrances or thoughts about Debbie Jin, please feel free to post them here.

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All Dressed Up and Ready to Probe

Steven Burrows — Thu, 28 Jul 2016 18:46:34 +0000

All Dressed Up and Ready to Probe Steven Burrows Thu, 07/28/2016 - 12:46

Julie Phillips / Science Communicator

A single impurity (shown as a round ball) entering a Bose-Einstein condensate (BEC) creates excitations that give researchers information about both the impurity used as the probe and the condensate. Image credit: Steven Burrows / JILA

Newly minted Ph.D. Ming-Guang Hu and his colleagues in the Jin and Cornell groups recently investigated immersing an impurity in a quantum bath consisting of a Bose-Einstein condensate, or BEC. The researchers expected the strong impurity-boson interactions to “dress” the impurity, i.e., cause it to get bigger and heavier. In the experiment, dressing the impurity resulted in it becoming a quasi particle called a Bose polaron.

“What we really did was study the behavior of the quantum bath when a potassium atom disturbed it,” said Fellow Deborah Jin. Jin said the impurity created excitations in the BEC that helped the researchers understand how the quantum bath responded to the potassium-atom impurity.

She also explained that because the impurity was moving through a BEC, the researchers called it a Bose polaron. Similarly, an impurity moving through a quantum bath of fermions, or Fermi Sea, would be called a Fermi polaron.

Jin said there is an interesting similarity between ultracold polarons and electrons moving through a crystal made of positively charged ions. For instance, scientists think of an electron moving through an ion crystal as a quasi particle. They observe that the farther an electron travels through an ion crystal, the more massive the quasi particle appears to be. As the interactions get stronger, the distortions of the lattice get larger, and the quasi particle moves more slowly.

“The atom gases give you a new way to explore that same phenomenon, but with a BEC and an impurity particle moving through it,” Jin said. “It turns out that it doesn’t matter what the quantum behavior of the impurity is because, in theory, you only have one particle, and it can be a fermion or a boson.”

Studies like this one where there is a single impurity moving through and interacting with a BEC are helping the Jin and Cornell groups plan for future investigations of a strongly interacting BEC in which all the bosons interact with each other.

“Experiments like this one allow you to see some of the same behavior you might see from an electron moving through a crystal,” Jin explained. “But our system isn’t a crystal. It’s continuous and has the ability to become strongly interacting under the right conditions.” Jin says this experiment has opened the door to a whole new area of exploration in ultracold physics.

This work appeared online as an Editor’s Suggestion in Physical Review Letters on July 28, 2016, alongside a closely related article by another group. The JILA researchers responsible for this trailblazing work include Hu, graduate students Michael J. Van de Graaff, Dhruv Kedar, and John P. Corson as well as Fellows Eric Cornell and Deborah Jin.

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The Ultramodern Molecule Factory: I. Doublons

Steven Burrows — Wed, 20 Apr 2016 19:01:06 +0000

The Ultramodern Molecule Factory: I. Doublons Steven Burrows Wed, 04/20/2016 - 13:01

The Jin-Ye group’s new method of creating just pairs of potassium (K) and rubidium (Rb) atoms (known as doublons) and nothing else inside a crystal of light (optical lattice) paves the way for upcoming JILA experiments in intermolecular communication, ultracold chemistry, and quantum simulation. Image credit: Steven Burrows / JILA

The old JILA molecule factory (built in 2002) produced the world’s first ultracold polar molecules [potassium-rubidium (KRb)] in 2008. The old factory has been used since then for ultracold chemistry investigations and studies of the quantum behavior of ultracold molecules and the atoms that form them. The Jin-Ye group, which runs the molecule factory, is now wrapping up operations in the old factory with experiments designed to improve operations in the ultramodern factory, which is close to completion.

Recently, graduate student Jacob Covey and both experimentalist and theorist colleagues came up with an ingenious way to ensure that every energy well in the crystal of light (optical lattice) inside a molecule factory is either (1) empty or (2) contains exactly one K and one Rb atom, both in their motional ground states, which is ideal for KRb molecule formation. The group also studied the conditions that kept the K atoms on top of the Rb atoms in the energy wells and the conditions that allowed the K atoms to just hop away.

Then, the researchers made the atom pairs form molecules in relatively deep energy wells with a special trick of using a magnetic field to induce a Feshbach resonance [1]. After using the Feshbach resonance to form the molecules, the researchers removed all the stray atoms from the experiment. Finally, they used the Feshbach resonance to turn the molecules back into atoms, leaving pairs of K and Rb atoms (called doublons) and nothing else in the crystal of light.

Once the group made the doublons, they characterized them and figured out how to avoid a tiny resonance that caused many unwanted KRb molecules to form in an excited state. Then they studied conditions that allowed one or both atoms to hop out of the energy wells so they could prevent these hops. This new information will allow the group to increase the fraction of lattice sites occupied by doublons inside a three-dimensional crystal of light. Increasing the filling fraction will open the door to studies of long-range intermolecular communications, ultracold chemistry, and quantum behaviors!

The researchers responsible for refining the production of ultracold KRb molecules for the ultramodern molecule factory include graduate students Jacob Covey and Matthew Miecnikowski, newly minted Ph.D. Steven Moses, research associates Martin Gärttner, Arghavan Safavi-Naini, and Johannes Schachenmayer, former research associate Zhengkun Fu, Fellows Ana Maria Rey, Deborah Jin, and Jun Ye as well as Paul Julienne of the Joint Quantum Institute.

This achievement will give the ultramodern molecule factory the capability of hosting experiments to explore the fundamental physics of not only the KRb molecules, but also of the individual K and Rb atoms. Plus, the new factory should be able to experimentally test theories that explain the interactions of bosons like the Rb atoms with fermions like the K atoms in an optical lattice. (Bosons are particles that don’t mind piling up in the same energy state, whereas only two fermions with opposite spin can occupy the same energy state.) The physics will likely be quite interesting when KRb molecules densely populate the crystal of light, as no one yet knows the microscopic details of how many quantum particles all talk to each other at the same time.

[1] A Feshbach resonance is a special magnetic-field strength where small changes in the magnetic field have dramatic effects on the interactions of atoms in an ultracold gas.

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