## Theory and Simulation

**Michael Gellar**

### Michael Geller

We are interested in several aspects of quantum computation, especially near-term approaches that do not require the overhead of full error correction.

My capabilities towards these include:

1. We have an extensive background on the design and operation of quantum computers based on superconducting qubits, currently a leading technology. We have designed two-qubit gates and tunable qubit-qubit couplers used by Google.

2. We have some experience with quantum algorithm development, especially algorithms related to quantum simulation. We have worked with Phillip Stancil on quantum algorithms for molecular collisions and chemical reaction simulation. And we are currently working with David Landau to develop modern (post-Metropolis) Monte Carlo algorithms for quantum computers. In early work with Phillip Stancil, we carried out one of the first resource estimates for doing error-corrected quantum simulation with the surface code. Our former PhD students currently work on quantum algorithm development and implementation at IBM, Ford, and Zapata.

3. Over the past few years we have been gaining experience running quantum computer prototypes via the cloud. We hope to develop this into a funded research program focused on low-overhead error correction. We have completed a few projects focused on correcting qubit readout/measurement errors. We have also developed our own software package called BQP to run quantum computers remotely and manage complex experiments.

4. In work with Phillip Stancil, and external collaborators at Google and LANL, we have proposed an alternative framework for doing quantum computation without error correction, called the single excitation subspace (SES) method, and we have strong theoretical evidence that it would outperform the conventional “quantum gate” model. It requires a fully connected array of qubits, a technology which does not yet exist, and I want to pursue the development of this framework. This is our highest priority.

I’m very interested in quantum information science course development. I’ve redesigned our graduate quantum physics courses Phys 8101/8102 from scratch, incorporating many modern concepts (including entanglement, quantum measurement, teleportation, open systems, Kraus evolution, and decoherence) and also computer simulation techniques that are left out of the traditional texts. I include a few lectures on quantum computing but want keep that separate. This is the fourth year I’ve taught the course and it is still a work in progress. I’m also in the early stages of writing a book to go with the course. In the future I’d like to develop a new 8000-level advanced graduate course on quantum information and computation.

I would also like to contribute to the development of a new 4000/6000 introductory course on quantum computing, but not lead that effort.

Since 2017, David Landau and I have organized the Southeast Quantum Computing Workshop at the Center for Simulational Physics. It is intended to be a highly interactive, student-friendly regional gathering of the quantum computing community, which is rapidly growing. In 2019 we had 5 invited speakers and approximately 40 registered participants.

**David Landau**

### David Landau

1. Capability in diverse Monte Carlo and molecular dynamics studies of materials and contributions of impurity atoms/ions to material properties. (current collaboration with Yohannes Abate)

2. Current collaboration with Mike Geller and student on implementing Monte Carlo simulations of quantum models on quantum computers (emphasis on Wang-Landau sampling, the most efficient algorithm for systems with complex free energy landscapes)

**Steve Lewis**

### Steve Lewis

I am interested in the properties of real materials (i.e., not model materials), and in particular understanding how the properties of materials emerge from their electronic and atomic structure.

Here is a list of capabilities my group has (in rough order of our level of experience):

1. First-principles Density Functional Theory and Density Functional Perturbation Theory for calculating properties derivable from the ground-state potential energy surface, including electron density, binding energies, structure, elastic constants, phonon modes and frequencies, electric polarization, reaction coordinates, barrier heights, etc. We apply this methodology to crystals (including metals, dielectrics, semiconductors, etc.), their surfaces, their lattice defects, crystal interfaces, nanocrystals, molecules, etc.

2. Various post-DFT quasiparticle methods, such as the GW approximation, for accurate calculations of electronic properties (band gaps, band widths, dispersion curves, densities of states, electronic spectral functions, etc.) and optical properties (optical constants, optical spectra, etc.)

3. Molecular dynamics simulation for studying dynamical and temperature-dependent properties of materials.

**Ping Ma**

### Ping ma

We are working on quantum machine learning. On one hand, we use machine learning algorithms for precise characterization of quantum systems. On the other hand, we integrate quantum algorithm to improve cutting edge machine learning methods.

**Bernd Schuttler**

### Bernd Schuttler

I am interested in applying numerical methods from quantum many-body theory to the study of nano-systems, including their electrical, optical and magnetic properties and responses. The following computational methods and expertise is available in my research group to address these issues

1) Diagrammatic techniques, including self-consistent RPA and conserving approximations.

2) Lanczos exact diagonalization methods for ground state and T=0 dynamical response properties.

**Phillip Stancil**

### Phillip Stancil

I am interested in chemical dynamics applications in Quantum Computing and on existing Quantum Computers. 1. Development of quantum simulation approaches for atom, ion, and molecule scattering 2. Applications of such approaches on cloud-based quantum computers 3. Exploration of computing resources for chemical dynamics simulations on classical and quantum computers 4. Use of public-domain quantum chemistry packages for quantum computers 5. Molecular dynamics/DFT simulations of quantum materials for QS applications (with Steve Lewis)

**Xianqiao Wang**

### Xianqiao Wang

I am interested in the aspects of Quantum Sensing via novel quantum materials and Quantum Computing via novel algorithms, especially in big data.

My capabilities towards these include:

1. My group can perform novel 2D metamaterial design from a molecular perspective by molecular dynamics simulation;

2. My group has the capability to develop novel computing algorithms suitable for big data analysis and quantum computing.

## Spectroscopy, Nanoscopy, Microscopy

**Yohannes Abate**

### Yohannes Abate

My group is interested in all aspects of quantum science including Quantum Sensing and Quantum Communication. My capabilities towards these include:

1. My group can image and perform spectroscopy of quantum emitters at a single photon level in a temperature range room temperature to 4 Kelvin.

2. My group can do nanoscale spectroscopy and imaging of quantum materials in a wavelength range UV to terahertz ( in eV units: 3 eV to 0.4 meV)

3. my group has the capability to image electrical conductivities, magnetic domains, electric potential distributions of quantum materials at nanometer scale spatial resolution.

**Eric Formo**

### Eric Formo

I am interested in:

1) Plasmonic field determination via energy loss spectroscopy in order to find both the 2D and 3D plasmonic tomography of a material.

2) How QS materials will age in the environment and if there are any ecological concerns

3) The creation of new QS materials for sensing and communication applications via low voltage electron beam based deposition methodologies

**Henning Meyer**

### Henning Meyer

My group applies different spectroscopies to characterize atoms and molecules in the gas-phase, their interactions among each other (van-der-Waals complex spectroscopy or molecular beam scattering) as well as with surfaces. To this end, we employ various non-linear multi-photon processes like REMPI or CARS to determine quantum state and velocity resolved product distributions characterizing the interaction of molecular species with 2D surface structures: Adsorption-desorption and photocatalytic reactions. The electron-hole dynamics relevant for the latter process is determined through in situ ns-us transient absorption spectroscopy. Initial ro-vibrational state preparation is accomplished through IR or Raman pumping. Available lasers cover the wavelength range from the UV to the near IR. These experimental techniques are complimented by high resolution spectroscopy in the GHz to THz regime allowing to probe the us time-evolution of a particular molecular quantum state.

**Tho Nguyen**

### Tho Nguyen

The research expertise of our group includes:

1) Spin injection, transport, and manipulation in semiconductors

2) Magneto-optical effect of magnetic films including 2D TMD

3) I am going to setup the single photon experiment.

**Melanie Reber**

### Melanie Reber

I am mostly interested in Quantum Sensing and Quantum fundamental science. I am not interested in Quantum Computer or Quantum Computers, but I sometimes work with similar technology.

My group studies the quantum mechanics of small molecules. To do this we develop new optical and spectroscopic techniques and laser systems.

Our capabilities include:

1. Building and developing fibers lasers and amplifiers and fiber-based supercontinuum generation. We have many standard fiber tools, such as a fusion splicer and expertise working with optical fiber.

2. Our light sources are generally frequency combs, which are both ultrafast and have high spectral resolution. Currently we can do ultrafast spectroscopy with ~100fs time resolution, we have some ultrafast pulse characterization tools and RF spectroscopy tools.

3. We are building a vacuum chamber to be able to study gas phase samples, specifically in molecular beams.

4. We do cavity-enhanced ultrafast spectroscopy, which has very high sensitivity, and employ many noise reduction techniques to get low noise level, often near the fundamental shot noise limit.

**Sussane Ullrich**

### Sussane Ullrich

A) Materials optical characterization:

1) Pump-probe spectroscopies for characterization of photoinduced processes:

Transient absorption spectroscopy

Femtosecond stimulated Raman spectroscopy

2) experimental conditions:

Ambient conditions (room temperature, air)

Cryostat (liquid nitrogen)

Magnetic field

Under high vacuum

Thin films or solution phase (flow cell, static cuvette, magnetic stirrer, free flowing thin film)

3) laser characteristics:

Pump wavelengths UV to NIR (200nm-800nm)

Probe broadband white-light (400nm-750nm)

Time resolution 130fs typical, but have capabilities to ~50fs

Max pump-probe delay ~700ps

Interested in:

novel materials to characterize with our pump-probe techniques

theoretical support for interpretation of data

B) Time-resolved gas-phase spectroscopy:

1) Time-resolved molecular spectroscopy:

Time-resolved photoelectron spectroscopy

Time-resolved mass spectrometry

2) experimental conditions:

Molecular beam in ultrahigh vacuum

3) laser characteristics:

Pump and probe pulses tunable to 200nm-800nm

130 fs

## Sample Fabrication and Engineering

**David Cotten**

### David Cotten

I am interested in all aspects of advancing space based technologies, this includes utilizing Quantum Sensing and Quantum Communication

My capabilities towards these include:

1. My group can build space rated systems that can incorporate these new QS technologies

2. My group can help transition terrestrial based QS technologies to space based systems

3. My group can incorporate QS into outreach events.

**Tina Salguero**

### Tina Salguero

Research in the Salguero group focuses on hybrid materials that incorporate nanosheet components. Nanosheets are characterized as well-defined nanomaterials that are one to several monolayers thick and tens of micrometers in lateral dimensions. Examples of nanosheets include graphene, graphite oxide, metal chalcogenides (MoS2, NbSe2) particularly some transition metal oxides (NbWO6, H2SrTa2O7, Ca2Nb3O10), hexagonal boron nitride, and lamellar perovskites.

**WenZhan Song**

### WenZhan Song

A link layer protocol for quantum networks https://dl.acm.org/doi/pdf/10.1145/3341302.3342070?download=true

Protocols for Packet Quantum Network Intercommunication https://pdfs.semanticscholar.org/0e1c/b3be5384c862af603db6553454fe4df89463.pdf

**Yiping Zhao**

### Yiping Zhao

My group is interested in both quantum sensing and communications, especially three topics: quantum plasmanics, quantum plasmodia sensing, and plasmonic-quantum material interaction. My group has the following capabilities: 1. A lots of experience in growing different plasmonic nano structures and meta materials 2. A versatile material characterization instruments 3. Strong experience in chemical and biological sensing, which could be one potential direction for quantum sensing 4. I hope to make Pan’s SEM system into a nano fabrication system (beam lithography), which is important for nano fabrication, especially to build quantum circuits for quantum science research. This is extremely important.

## Educational Activities, Curriculum Development, Outreach

**Craig Wiegert**

### Craig Wiegert

My primary strengths and interests for this group would be the following:

· Working with other group members on developing curricular materials. These could be at the undergraduate or graduate level, as just a piece of a more general QM course, or imaging/spectroscopy course, or materials course, or simulations course. Or they could be for a more specialized elective/seminar.

· There could be some potential for education research in these courses (studying students’ understanding of various quantum physics concepts).

· Working with other group members and their host departments to develop a graduate or undergraduate certificate program in quantum science.

· Developing potential school/public outreach activities and high-school/Young Dawgs programs.