Research Interests

Ultra-low Temperature Physics

Basic and Applied Superconductivity

Superconducting Quantum Computing

Two-Dimensional Quantum Fluids

Renewable Energy

Nanomaterials

Physics Education

My experimental research expertise is in the area of quantum science and technology and low-temperature condensed matter physics. For my Ph.D. dissertation, I worked with Prof. Oscar Vilches to map the thermodynamic phases (2D liquid, 2D vapor, 2D solid) in quantum fluids - of single atomic layers of He-3/He-4 mixtures adsorbed on H2-plated graphite at 0.2 Kelvin. My expertise with helium dilution refrigerators and interest in macroscopic quantum mechanics led me to do my postdoc in 1999 in experimental quantum computing at the University of Maryland's Center for Superconductivity Research, under Fred Wellstood and Chris Lobb. In the late 1990's, we helped pioneer superconducting quantum computing by being the first to propose the Josephson junction phase qubit and measuring quantum entanglement between two capacitively-coupled Josephson phase qubits at near Absolute Zero temperatures. I later expanded my interest in exploring how quantum mechanics manifests in larger-sized physical objects by studying large, almost mm-sized Josephson junctions made with multi-gap superconductors and measured resonant activation and other macroscopic quantum effects in these. My lab also measured transport properties in graphene nanoscale devices, MgB2 heterojunctions, iron-based superconductors (pnictides), and solar cells. Having taught quantum information at both graduate and undergraduate levels, I am developing a Quantum Engineering course that infuses quantum information science and quantum computing experiments.

Energy Gap Measurements in Multi-gap Superconductors

Microwave Resonant Activation in Micro and Mesoscale Devices

Transport Properties of Graphene-based Devices

Two-Dimensional 4He shows 2D Gas to 2D Liquid Phase Transition (peak) at 0.91 Kelvin while 2D 3He behaves as a Fermi fluid.

Spectroscopic Demonstration of Quantum Entanglement between two superconducting qubits (Josephson Phase Qubits) separated but coupled with a capacitor.

Demonstration of Microwave Resonant Activation in a MgB2 Josephson Junction at 23 milliKelvin.

Select Grant-related Publications:

Energy-Gap Substructures in Conductance Measurements of MgB2 -based Josephson Junctions: Beyond the Two-Gap Model

Microwave resonant activation in hybrid single-gap/two-gap Josephson tunnel junctions

Momentum-dependent multiple gaps in magnesium diboride probed by electron tunnelling spectroscopy

Differential Conductance Measurements of MgB2-Based Josephson Junctions Below 1 Kelvin

Probing the Energy Gaps of a Multi-Gap Superconductor: Ba(1-x)KxFe2As2

Dan Fauni (SJU Physics Class of 2023) now works as an Engineer in EOS Energy, a renewable energy company specializing in energy storage. Posing beside our 2 Kelvin cryocooler and 3He cryostat (0.3 Kelvin).

Dr. Joey Lambert (second from right), my former Ph.D. student and postdoc who worked on graphene and novel superconductivity, currently works at the National Radio Astronomy Observatory in Virginia. Oberon Wackwitz (second from left) is a Ph.D. in Physics student at Texas State University. Luke Conover works at Lockheed Martin in Pennsylvania.

Oberon Wackwitz (left) presents a contributed talk at the APS March Meeting. Luke Conover (right) presents his NSF-supported research poster and poses with Pennsylvania State Representative James Roebuck at the Undergraduate Research at the Capitol.

Promoting Quantum Science and Quantum Computing

Dr. Ramos discusses multigap superconductivity in January 2019 with graduate students and physics faculty at the Physics Department of the Ateneo de Manila University, second-oldest, Jesuit-administered institution of higher learning in Asia-Pacific.

Dr. Ramos gave a research talk on "Adventures in the Quantum World: From Quantum Science to Quantum Computing" at the Physics Department, De La Salle University, a top Catholic research university in the Philippines on July 2024.

Dr. Ramos (seated leftmost) was one of the speakers at the 2017 Jagna International Workshop on Structure, Function and Dynamics: From nm to Gm in Bohol, Philippines.

Former Research Mentees (Graduate/Undergraduate)

Dan Ashley-Fauni (Engineer, EOS Energy)
Keeran Ramanthan (Data Analyst, Quality Reimbursement Services)
Oberon Wackwitz (Physics Ph.D. Student, Texas State University)
Brett Conti, (Software Specialist, ASRC Federal, Moorestown, NJ)
Luke Conover (E3 Systems Engineer, Lockheed Martin, Moorsetown, NJ)
Joey Lambert, Ph.D. ( Staff Scientist, National Radio Astronomy Observatory, Virginia)
Steve Carabello, Ph.D. (Associate Teaching Professor of Physics, Penn State Harrisburg)
Caitlyn McConnell (Ph.D. student, Saint Joseph's University)
Alex Waters (Electrical Process and Design Engineer, L3Harris)
Matthew Eckardt (Lab Supervisor, Creative Testing Solutions)
Chandler Chapman (R&D Strategy Consultant, Elanco Pharmaceuticals)
Wenli Bi, Ph.D. (Associate Professor of Physics, Univ of Alabama - Birmingham)
Jerome Mlack, Ph.D. (Senior Principal Physicist, Northrup Grumman Corporation)
David Cusick, M.S. (Physics Ph.D. student, University of Oxford; currently Lab Operations Manager, Plasma Science & Fusion Center, M.I.T.)
Michael Bowman, Ph.D. (Asst Professor of Chemistry, Taylor University)
Angela Garriott Matteson (Analyst, Community Health Network)
Josh Ostrander, Ph.D. (Researcher, Institute for Defense Analyses )
Heath Rose, Ph.D. (Associate Director, Guidehouse)
Alyssa Wilson, Ph.D. (Research Assistant Professor, Icahn School of Medicine at Mount Sinai)
Yuanxin Sun (Google, Singapore)
Despina Nakos, M.S. (Physics Teacher, Philadelphia School District)

Virtual Lab Tour led by a Physics Major

Quantum Materials Laboratory: Probing Quantum Mechanics at Low Temperatures

Our Quantum Materials Physics Laboratory has low-temperature transport characterization facilities that allow us to study electrical transport and quantum mechanical properties in materials and devices. Recent focus is on the studying the energy gap of novel superconductors and quantum and classical behavior of Josephson Junctions. We have a cryocooler that goes down to 2 Kelvin (2 degrees above absolute zero) in under two hours, and a helium-3 cryostat that has a base temperature of 330 milli-Kelvin. Our student research collaborators are trained in the area of ultra-low temperature physics and routinely present papers at international conferences, including the American Physical Society meetings.