HQI Colloquium - Prof. Andreas Heinrich
Wednesday, February 14, 2024
Jefferson 250
Andreas Heinrich, IBS Center for Quantum Nanoscience, Ewha Womans University
Title: "Towards Quantum Computing with Spins on Surfaces"
There is a strong international research effort in the area of quantum information
science. Here, the concepts of quantum coherence, superposition and entanglement of
quantum states are exploited. These concepts were originally shown with photons as well as
atoms and ions in vacuum traps. Over the past two decades, many advances at studying such
quantum coherence in solid-state and molecular architectures have evolved [1].
In this talk we will focus on quantum-coherent experiments in Scanning Tunneling
Microscopy (STM). STM enables the study of surfaces with atomic-scale spatial resolution
and offers the ability to study individual atoms and molecules on surfaces. Here at Ewha,
we have one of the world's best facilities for such studies. STM can also be used to
move atoms with atomic-scale precision, which enables us to build engineered
nanostructures where each atom is in the exactly correct place.
In order to study qubits with STM, we recently learned how to combine STM with electron
spin resonance [2,3]. Spin resonance gives us the means to quantum-coherently control an
individual atomic or molecular spin on a surface. Using short pulses of microwave
radiation further enables us to perform qubit rotations and learn about the quantum
coherence times of our spins [4]. Finally, we will finish with recently published results
on multi-qubit operations with spins on surfaces.
Mengke Liu, Hoffman Group
Title: "Visualizing momentum-dependent Kondo coupling in a correlated van der Waals
heavy fermion system"
In systems containing f-orbitals, the exchange interaction between localized f-electron
moments and itinerant electrons, known as Kondo coupling, is the key concept in
understanding the complex phase diagrams of heavy fermions. In a newly discovered 2D van
der Waals system, UOTe, we employed scanning tunneling microscopy/spectroscopy and
quasi-particle interference to directly visualize this Kondo coupling behavior. This
includes the observation of flat bands originating from the 5f electrons and an avoided
crossing between these flat bands and the conduction bands. Additionally, we identified
distinct avoided crossing behaviors along the Gamma-M and Gamma-X/Y directions. This study
establishes UOTe as a unique system for investigating momentum-dependent Kondo
interactions.
Student presentation by Mengke Liu at 4:00 PM
Coffee break from 4:10-4:30 PM
Guest Presentation will begin at 4:30 PM
Claire M. Gallagher
Staff Assistant III
Harvard Quantum Initiative
33 Oxford Street, MD 351
Cambridge, MA 02138
P. (617) 496-2361
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HQI Colloquium - Prof. Andreas Heinrich
Wednesday, February 14, 2024
Jefferson 250
Andreas Heinrich, IBS Center for Quantum Nanoscience, Ewha Womans University
Title: "Towards Quantum Computing with Spins on Surfaces"
There is a strong international research effort in the area of quantum information
science. Here, the concepts of quantum coherence, superposition and entanglement of
quantum states are exploited. These concepts were originally shown with photons as well as
atoms and ions in vacuum traps. Over the past two decades, many advances at studying such
quantum coherence in solid-state and molecular architectures have evolved [1].
In this talk we will focus on quantum-coherent experiments in Scanning Tunneling
Microscopy (STM). STM enables the study of surfaces with atomic-scale spatial resolution
and offers the ability to study individual atoms and molecules on surfaces. Here at Ewha,
we have one of the world's best facilities for such studies. STM can also be used to
move atoms with atomic-scale precision, which enables us to build engineered
nanostructures where each atom is in the exactly correct place.
In order to study qubits with STM, we recently learned how to combine STM with electron
spin resonance [2,3]. Spin resonance gives us the means to quantum-coherently control an
individual atomic or molecular spin on a surface. Using short pulses of microwave
radiation further enables us to perform qubit rotations and learn about the quantum
coherence times of our spins [4]. Finally, we will finish with recently published results
on multi-qubit operations with spins on surfaces.
Mengke Liu, Hoffman Group
Title: "Visualizing momentum-dependent Kondo coupling in a correlated van der Waals
heavy fermion system"
In systems containing f-orbitals, the exchange interaction between localized f-electron
moments and itinerant electrons, known as Kondo coupling, is the key concept in
understanding the complex phase diagrams of heavy fermions. In a newly discovered 2D van
der Waals system, UOTe, we employed scanning tunneling microscopy/spectroscopy and
quasi-particle interference to directly visualize this Kondo coupling behavior. This
includes the observation of flat bands originating from the 5f electrons and an avoided
crossing between these flat bands and the conduction bands. Additionally, we identified
distinct avoided crossing behaviors along the Gamma-M and Gamma-X/Y directions. This study
establishes UOTe as a unique system for investigating momentum-dependent Kondo
interactions.
Student presentation by Mengke Liu at 4:00 PM
Coffee break from 4:10-4:30 PM
Guest Presentation will begin at 4:30 PM