Workshop on Quantum Information & Quantum Computation at Texas Tech
Monday, 10 August 2020 from to (America/Chicago)
The purpose of this workshop is to introduce current research projects on quantum information and quantum computation at Texas Tech Univ. to teaching and research communities on-campus. Join Zoom Meeting https://zoom.us/j/99107703270?pwd=NHN5Q2dkMXpCZjBueG1Eb0toWVZsZz09 Meeting ID: 991 0770 3270 Passcode: 467805 One tap mobile +13462487799,,99107703270# US (Houston) +12532158782,,99107703270# US (Tacoma) Dial by your location +1 346 248 7799 US (Houston) Meeting ID: 991 0770 3270 Find your local number: https://zoom.us/u/aEqMr5NOj
Go to day
10:00 - 10:20
10:20 - 11:05
Session I: Quantum Algorithms
Quantum algorithms for mathematical optimization
A mathematical optimization problem consists in finding the maximum or minimum of a function defined over an arbitrary set (typically Rn) and taking values on R. Mathematical optimization arises in a wide variety of applications, e.g. hospital personnel management, transportation, stock market investment, and sports scheduling. The ability to solve such models efficiently is critical for these applications. I will show how quantum computing speeds up the solution to optimization models and an innovative quantum computing approach to tackle them.
Speaker: Ismael Regis de Farias Jr. (Texas Tech Univ.) Material: Slides
Efficient evaluation of exponential and Gaussian functions on a quantum computer
The exponential and Gaussian functions are some of the most fundamental and important operations, appearing ubiquitously throughout all areas of science, engineering, and mathematics. Whereas formally, it is well-known that any function may in principle be realized on a quantum computer, in practice present-day algorithms are extremely inefficient, requiring orders of magnitude more computational effort than say, a multiplication. In this talk, we will present a new algorithm for evaluating Gaussian and exponential functions efficiently on quantum computers. The cost is comparable to that of a fairly small number of multiplications, and moreover, the algorithm is amenable to error correction.
Speaker: Bill Poirier (Texas Tech Univ.) Material: Slides
Quantum computing of quantum chemistry
Speaker: Prof. Jorge Morales (Texas Tech University) Material: Slides
- 10:20 Quantum algorithms for mathematical optimization 15'
- 11:05 - 11:20 Virtual Coffee Break
11:20 - 12:25
Session II: Quantum Materials and Realization
Measurements of the onset of macroscopic matter wave coherence in liquid helium, and other topics in quantum sensing and quantum-limited measurements
Experimental measurements of the interfacial thermal profile near the superfluid transition under a heat flux provide data on the onset of superfluid matter wave coherence, and these data provide an excellent test of renormalized field theories that are relevant not only to this, but also to all other analogous problems, such as spontaneous symmetry breaking in theories of the early universe. I will review the extensive data that we have taken already on Earth, and published in many Physical Review Letters, and summarized in Reviews of Modern Physics articles in the past. A full comparison to theory will require data taken in either long-duration free fall, such as on Earth or Lunar orbit, or from measurements under the reduced gravitational acceleration of the lunar surface. If time permits, then I will also discuss near quantum-limited magnetic flux measurements using SQUIDs (Superconducting Quantum Interference Devices) and more recently in optical measurements of nitrogen vacancies in diamond. These results may be used to propose major new research efforts to NASA, and to other funding agencies with interest in the National Quantum Initiative (NQI).
Speaker: Prof. Robert Duncan (Texas Tech) Material: Slides
Many-body systems and quantum information
In this talk, I will summarize current and proposed research in the area of quantum information, highlighting areas of potential collaboration. The primary focus of our work is on quantum materials---systems in which quantum information can be stored, processed, and accessed. Topological electron systems, superconducting circuits, and select photonic materials are at the center of these efforts. Each of these many-body systems possesses a low-energy spectrum involving only a few quantum degrees of freedom that are protected by an energy gap. A central question we seek to address is how quantum optical technology can be used to prepare, manipulate, and detect these degrees of freedom, particularly in strongly correlated electron systems such as one-dimensional electron liquids and fractional quantum Hall droplets. On the other hand, recent work has explored how the coupling of light and matter offers a novel probe of many-body quantum systems. This is part of a broader research strategy that seeks to leverage technological advances and insights from the field of quantum information to explore fundamental many-body physics. For example, we are currently looking to apply quantum neural networks, a type of machine learning protocol, to study and categorize many-body wave functions and quantum phases. This work would greatly benefit from experimental collaboration. Experimental achievements in the field also offer new ways to explore many-body physics. For example, the ability to fabricate superconducting circuits has been a boon to the field of quantum information. We are particularly interested in exploring how this technology can be used to realize exotic and novel many-body physics.
Speaker: Wade DeGottardi (Texas Tech Univ.) Material: Slides
Anomalous quantum oscillations in a spin-3/2 topological semimetal
The intrinsic electron spin s=1/2 and its orbital angular momentum l are often blended due to relativistic orbital motion. This spin-orbit coupling (SOC) can be significantly strong in compounds containing heavy elements, and therefore the total angular momentum, or effective spin, j, becomes the relevant quantum number. We report compelling evidence for a j=3/2 Fermi surface in the topological half-Heusler superconductor YPtBi via studies of the angle-dependent Shubnikov-de Haas effect, which exhibits an amplitude variation that is strikingly anisotropic for such a highly symmetric cubic material. We show that the anomalous anisotropy is uniquely explained by the spin-split Fermi surface of j=3/2 quasiparticles, and therefore confirm the existence of the long-sought high-spin nature of electrons in the topological RPtBi (R=rare earth) compounds. This work offers a thorough understanding of the j=3/2 fermiology in RPtBi, a cornerstone for realizing topological superconductivity and its application to fault-tolerant quantum computation.
Speaker: Hyunsoo Kim (Texas Tech Univ.) Material: Slides
On-chip quantum information processing based on a rare-earth spin qubit in active nanostructures
Rare-earth spin qubits are a promising quantum system because of narrow energy level transition, as well as long optical and spin coherence lifetimes at visible and near infrared. Numerous materials host rare-earth spin qubits including yttrium orthosilicate, yttrium aluminum oxide, and lithium niobate, all of which essentially resist decoherence of the quantum state caused by hosting material interactions. The hosting material should be CMOS-compatible to integrate with classical photonic circuits. CMOS-compatible materials are easily structured in nanoscale to create waveguides or optical cavities and enhance light-matter interaction for a long photon lifetime. However, current rare-earth doped systems are far from CMOS-compatible. Here, I will present our efforts to develop on-chip quantum information processing devices based on rare-earth spin qubits in CMOS-compatible and active material platform. Erbium ion has been chosen as a spin qubit since its atomic level transition is in telecom which will benefit an integration into on-chip silicon photonic devices. We prepare a single erbium ion attached to VO2 nanorod. VO2 is selected as CMOS-compatible and an active material platform because of the thermally driven insulator-metal transition, and its refractive index is similar to silicon. We will identify the spin qubit system and integrate them into a photonic waveguide to explore potential on-chip quantum communication and sensing applications.
Speaker: Prof. Myoung-Hwan Kim (Texas Tech University) Material: Slides
Quantum light emitters (single photon sources)
In this talk I will provide an overview of the basic quantum computing concepts, and I will describe the single-photon emitters. Single-photon sources are an essential building block for realizing quantum information processing devices. Many research groups are investigating single-photon sources based on a wide range of fluorescent defects hosted in 3D materials, including the nitrogen vacancy and silicon vacancy defects in diamonds, known as the carbon antisite-vacancy pair in a large bandgap silicon carbide, and zinc vacancies in ZnO. However, the light-extraction efficiency of single-photon sources embedded in 3D materials is limited by the internal reflections in a high refractive index material. In contrast, 2D materials do not suffer from these problems. There have been already observed 2D quantum emitters from localized vacancy-related defects in hexagonal boron nitride (h-BN) and tungsten disulfide (WS2). The 2D materials can be stacked up to build heterostructures, which enable higher quantum efficiencies and new line emission. The stability of the defects in room temperature 2D materials and their high emission rate enable them to be easily coupled with nanostructures (metasurfaces) where the Purcell factors would largely be enhancing and control the spontaneous emission. Thus, 2D materials are considered to be the best candidates for practical applications in quantum information processing.
Speaker: Ioannis Chatzakis (Texas Tech University) Material: Slides
- 11:20 Measurements of the onset of macroscopic matter wave coherence in liquid helium, and other topics in quantum sensing and quantum-limited measurements 15'
12:25 - 13:10
Round Table Discussion
13:10 - 13:15
- 10:00 - 10:20 Welcome Session