Porto Research Group

Photons—the quantum particles of light—normally don’t have any sense of personal space. A laser crams tons of photons into a tight beam, and they couldn’t care less that they are packed on top of each other. Two beams can even pass through each other without noticing. This is all well and good when making an extravagant laser light show or using a laser level to hang a picture frame straight, but for researchers looking to develop quantum technologies that require precise control over just one or two photons, this lack of interaction often makes life difficult. Now, a group of UMD researchers has come together to create tailored interactions between photons in an experiment where, at least for photons, two’s company but three’s a crowd. The technique builds on many previous experiments that use atoms as intermediaries to form connections between photons that are akin to the bonds between protons, electrons and other kinds of matter. These interactions, along with the ability to control them, promises new opportunities for researchers to study the physics of exotic interactions and develop light-based quantum technologies.

Sandy is a doctor now!  He successfully defended his thesis, "Rydberg Ensembles for Quantum Networking" on August 7th. Congratulations, Sandy!

Dalia graduates!  Dr. Dalia's thesis, "Experiments with Strongly-Interacting Rydberg Atoms", was successfuly defended on the Ides of July.  Congratulations, Dalia!

After more than 12 years in the Atlantic building, the rubidium/ytterbium mixtures experiment is moving to the Physical Sciences Complex.  The old experiment has been disassembled, with help from the PI's. 

Scientists at the Joint Quantum Institute (JQI) have observed, for the first time, interference between particles of light created using a trapped ion and a collection of neutral atoms. Their results could be an essential step toward the realization of a distributed network of quantum computers capable of processing information in novel ways.

JQI researchers have demonstrated a new way to obtain the essential details that describe an isolated quantum system, such as a gas of atoms, through direct observation. The new method gives information about the likelihood of finding atoms at specific locations in the system with unprecedented spatial resolution. With this technique, scientists can obtain details on a scale of tens of nanometers—smaller than the width of a virus. The new experiments use an optical lattice—a web of laser light that suspends thousands of individual atoms—to determine the probability that an atom might be at any given location. Because each individual atom in the lattice behaves like all the others, a measurement on the entire group of atoms reveals the likelihood of an individual atom to be in a particular point in space. Published in the journal Physical Review X, the technique (similar work was published simultaneously by a group at the University of Chicago) can yield the likelihood of the atoms’ locations at well below the wavelength of the light used to illuminate the atoms—50 times better than the limit of what optical microscopy can normally resolve. 

In a joint publication with Cheng Chin's group, we demonstrated subwavelength imaging of atomic wavefuncion density: PRX 9 21002 (2019), See Physics Viewpoint 

Our study of heating mechanisms of a BEC in a periodically modulated 2D optical lattice came out: PRX 9, 011047 (2019).