Research Highlights

Atomic & Molecular Physics | Quantum Information Science & Technology
A Magic Recipe for a Quantum Interferometer
A comparison of two optical cavities, with the left cavity having only localized atoms and no squeezing. In contrast, the right cavity depicts delocalized atoms, squeezing and entanglement.
Published: November 17, 2021

Gravimetry, or the measurement of the strength of a gravitational field (or gravitational acceleration), has been of great interest to physicists since the 1600s. One of the most precise ways to measure gravitational acceleration is to use an atom interferometer. There are many different types of atom interferometers but so far all operate using uncorrelated atoms that are not entangled. To build the best one allowed in nature, it requires harnessing the power of quantum entanglement. However, making a quantum interferometer with entangled atoms is challenging. JILA Fellows Ana Maria Rey and James K. Thompson have published a paper in Physical Review Letters that discusses a new protocol that could make entangled quantum interferometers easier to produce and use.

PI: Ana Maria Rey | PI: James Thompson
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Laser Physics | Quantum Information Science & Technology
BCS: Building a Cavity Superconductor
Model of an optical cavity
Published: May 18, 2021

The idea of quantum simulation has only become more widely researched in the past few decades. Quantum simulators allow for the study of a quantum system that would be difficult to study easily and quickly in a laboratory or model with a supercomputer. A new paper published in Physical Review Letters, by a collaboration between theorists in the Rey Group and experimentalists in the Thompson laborator,y proposes a way to engineer a quantum simulator of superconductivity that can measure phenomena so far inaccessible in real materials. 

PI: Ana Maria Rey | PI: James Thompson
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Atomic & Molecular Physics
Phases on the Move: A Quantum Game of Catch
Phase transitions in a dynamic system
Published: April 29, 2020

The world is out-of-equilibrium, and JILA scientists are trying to learn what rules govern the dynamic systems that make our universe so complex and beautiful, from black holes to our living bodies.

PI: Ana Maria Rey | PI: James Thompson
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Atomic & Molecular Physics | Precision Measurement | Quantum Information Science & Technology
Twisting Atoms to Push Quantum Limits
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Published: August 13, 2018

The chaos within a black hole scrambles information. Gravity tugs on time in tiny, discrete steps. A phantom-like presence pervades our universe, yet evades detection. These intangible phenomena may seem like mere conjectures of science fiction, but in reality, experimental comprehension is not far, in neither time nor space. Astronomical advances in quantum simulators and quantum sensors will likely be made within the decade, and the leading experiments for black holes, gravitons, and dark matter will be not in space, but in basements – sitting on tables, in a black room lit only by lasers.

PI: Ana Maria Rey | PI: James Thompson
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Atomic & Molecular Physics
A Little Less Spontaneous
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Published: June 29, 2018

A large fraction of JILA research relies on laser cooling of atoms, ions and molecules for applications as diverse as world-leading atomic clocks, human-controlled chemistry, quantum information, new forms of ultracold matter and the search for new details of the origins of the universe. JILAns use laser cooling every day in their research, and have mastered arcane details of the process.

PI: James Thompson | PI: Murray Holland
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Laser Physics
Lassoing Colors with Atomic Cowpokes
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Published: July 10, 2017

Getting lasers to have a precise single frequency (color) can be trickier than herding cats. So it’s no small accomplishment that the Thompson group has figured out how to use magnetic fields to create atomic cowpokes to wrangle a specific single color into place so that it doesn’t wander hither and yon. The researchers do this with a magnetic field that causes strontium atoms in an optical cavity to stop absorbing light and become transparent to laser light at one specific color. What happens is that the magnetic field creates a transparent window that serves as a gate to let only light of a single frequency pass through.

PI: James Thompson
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Quantum Information Science & Technology
The Quantum Identity Crisis
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Published: October 14, 2014

Dynamical phase transitions in the quantum world are wildly noisy and chaotic. They don’t look anything like the phase transitions we observe in our everyday world. In Colorado, we see phase transitions caused by temperature changes all the time: snow banks melting in the spring, water boiling on the stove, slick spots on the sidewalk after the first freeze. Quantum phase transitions happen, too, but not because of temperature changes. Instead, they occur as a kind of quantum “metamorphosis” when a system at zero temperature shifts between completely distinct forms.

PI: James Thompson | PI: Murray Holland
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Atomic & Molecular Physics
Quantum Entanglement
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Published: July 13, 2014

The spooky quantum property of entanglement is set to become a powerful tool in precision measurement, thanks to researchers in the Thompson group. Entanglement means that the quantum states of something physical—two atoms, two hundred atoms, or two million atoms—interact and retain a connection, even over long distances.

PI: James Thompson
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Laser Physics
The Heart of Darkness
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Published: December 18, 2012

When the Thompson group first demonstrated its innovative “superradiant” laser the team noticed that sometimes the amount of light emitted by the laser would fluctuate up and down.  The researchers wondered what was causing these fluctuations. They were especially concerned that whatever it was could also be a problem in future lasers based on the same principles.

PI: James Thompson
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Atomic & Molecular Physics
The Entanglement Tango
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Published: December 05, 2012

Most scientists think it is really hard to correlate, or entangle, the quantum spin states of many particles in an ultracold gas of fermions. Fermions are particles like electrons (and some atoms and molecules) whose quantum spin states prevent them from occupying the same lowest-energy state and forming a Bose-Einstein condensate. Entanglement means that two or more particles interact and retain a connection. Once particles are entangled, if something changes in one of them, all linked partners respond.

PI: Ana Maria Rey | PI: James Thompson
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Laser Physics
The Laser with Perfect Pitch
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Published: April 04, 2012

The Thompson group, with theory help from the Holland group, recently demonstrated a superradiant laser that escapes the “echo chamber” problem that limits the best lasers. To understand this problem, imagine an opera singer practicing in an echo chamber. The singer hears his own voice echo from the walls of the room. He constantly adjusts his pitch to match that of his echo from some time before. But, if the walls of the room vibrate, then the singer’s echo will be shifted in pitch after bouncing off of the walls. As a result, if the singer initially started singing an A, he may eventually end up singing a B flat, or a G sharp, or any other random note — spoiling a perfectly good night at the opera.

PI: James Thompson
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Atomic & Molecular Physics | Precision Measurement
Sayonara Demolition Man
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Published: November 30, 2010

The secret for reducing quantum noise in a precision measurement of spins in a collection of a million atoms is simple: Pre-measure the quantum noise, then subtract it out at the end of the precision measurement. The catch is not to do anything that detects and measures the spins of individual atoms in the ensemble. If states of individual atoms are measured, then those atoms stop being in a superposition and the subsequent precision measurement will be ruined.

PI: James Thompson
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