Research of the Carroll Group
Where does our science come from and where is it done now?
The research of the Carroll Group must be seen in continuity with Siegmar Roth's 4C11 group at MPI-FKF in Stuttgart, Germany. Interests and approaches overlap strongly and share in perspective. Though Dr. Roth has since retired, he, and his students remain active collaborators and friends - influencing the directions of the group at WFU.
image left - Siegmar's birthday conference (2015) and meeting of the 4C11 Society. Held at the MPI-FKF in Busnau outside of Stuttgart.
The 4C11 Society is a group of Friends, Influencers and Colleagues, from the steps of the MPI-FKF to the world. The Carroll group has very strong ties to the Max Planck fur Festkorperforschung, Max-Planck fur Metallforschung, as well as several Fraunhofer Institute. Many of these collaboratives still meet regularly through the 4C11 Society
Today our work is carried out at the Nano/Quantum Technologies Laboratory (NanoteQ), a research center of Wake Forest University in Winston Salem NC. The facility is incredibly well equipped and allows us access to materials synthesis high resolution TEM/EELS/EDX characterization, scanning probes STM/MFM/AFM, optical characterization (Raman/transient absorption/etc.) and a full scale ISO 5 cleanroom microfabrication and integration of quantum circuits facility. This combined with facilities to do magneto-transport at 10 mK and 12T (3 different fridges) and full scale quantum tomography, NanoteQ is very much like the MPI where we began.
What do we do? The Science of the Lab
Abstract
Material objects are typically described in terms of order, dimension, and bonding. This yields a series of properties which are generally predictable and unremarkable. However, there are some unusual materials where there is strong correlation and coherence of the carrier wavefunction, that is, the components of the solid behave more quantum than statistical. In these objects we must define a quantum geometry and k-space topology for the system to describe properties and to understand their emergence.
A consequence of these new quantum-based properties in solids is that unusual new ways of thinking about those properties must invented. The language of quantum information theory becomes a natural way of communicating these ideas and with this, a new way of thinking about such solids is born.
Such material exotica are not nearly as rare as one might think however. Topology begins with the SSH model - 1D conjugated polymers! Chalcogenides in 2D and even graphene also are described this way. Our group studies this quantum zoo, how they occur, their magnetic and electronic nature, the interplay between quantum geometry and band topology, and their interactions with fields.
We are experimentalists and we push the boundaries of theory with novel materials and technologies. This is especially true of our work in:
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Quantum computation systems, qubits based on topological insulators multi-qubit registers for quantum logic studies and Floquet-driven approaches to dynamic qubit control with advanced error correction.
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Polymers and polymer devices (1D SSH topologies), as well as nano carbons such as graphene and SWNTS. These systems allow us to push the boundaries of extreme use scenarios.
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Exotica: materials such as chiral topological structures, Corbino geometries in spin Hall insulators, Kagome Lattices and Altermagnets.
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Onsager thermodynamics and quantum Fisher information metrics, thermodynamic entanglement.
Thus, an unusual characteristic of our work is how it integrates advanced tech like information and power systems (quantum computers / quantum batteries), with the symmetries and invariants of quantum field theory in topological materials. So, our studies of Onsager thermodynamics in organic thermo/piezo -electric generators, spin state engineering in polymer light emitting systems, and topological insulators in quantum information systems all arise from the same basic set of principles. These principles are derived from the interaction between the quantum geometry that can be engineered into a system - say set by a device architecture - and its band topology.
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