Abstract: We believe quantum error correction is necessary to build a large-scale quantum computer, and the leading error correction code is called the surface code. Currently, most hardware endeavors are focused on building qubits with error rates slightly below the threshold where the surface code safeguards the computation. Unfortunately, this approach necessitates an excessive number of physical qubits to create a single logical qubit. In this talk, I will discuss some novel approaches to building a quantum computer that may alleviate this problem by building better physical qubits. Ultimately these better qubits would still be encoded into a surface code. The first approach I will explore involves the development of inherently error-protected qubits. These qubits are designed to have several orders of magnitude fewer errors compared to today's qubits. The realization of these qubits could substantially reduce the number of physical qubits required for quantum computation. The second approach involves encoding a qubit into a harmonic oscillator and actively performing error correction. Surprisingly the best error-corrected qubit in the world (at the moment) is of this variety and developed by an academic lab rather than a large company specializing in quantum computing. Lastly, I will discuss a novel scheme for quantum computation inspired by the Rubik's cube. I will show that permuting a collection of distinguishable and indistinguishable fermions on a 2D lattice, with some additional operations, can lead to universal quantum computation.

Bio: Josh Combes completed his PhD in theoretical Physics in 2010 and held several fellowships until joining CU in 2020. Over his career he has worked on several aspects of theoretical quantum physics with an emphasis on quantum sensing, measurement, light-matter interaction, and quantum computing. In 2016 he was a recipient of an Australian Research Council fellowship known as the “discovery early career researcher award” (DECRA). Prior to that, he held independent postdoctoral fellowships at the Perimeter Institute for Theoretical Physics and the Institute for Quantum Computing.

Abstract: We believe quantum error correction is necessary to build a large-scale quantum computer, and the leading error correction code is called the surface code. Currently, most hardware endeavors are focused on building qubits with error rates slightly below the threshold where the surface code safeguards the computation. Unfortunately, this approach necessitates an excessive number of physical qubits to create a single logical qubit. In this talk, I will discuss some novel approaches to building a quantum computer that may alleviate this problem by building better physical qubits. Ultimately these better qubits would still be encoded into a surface code. The first approach I will explore involves the development of inherently error-protected qubits. These qubits are designed to have several orders of magnitude fewer errors compared to today's qubits. The realization of these qubits could substantially reduce the number of physical qubits required for quantum computation. The second approach involves encoding a qubit into a harmonic oscillator and actively performing error correction. Surprisingly the best error-corrected qubit in the world (at the moment) is of this variety and developed by an academic lab rather than a large company specializing in quantum computing. Lastly, I will discuss a novel scheme for quantum computation inspired by the Rubik's cube. I will show that permuting a collection of distinguishable and indistinguishable fermions on a 2D lattice, with some additional operations, can lead to universal quantum computation.

Bio: Josh Combes completed his PhD in theoretical Physics in 2010 and held several fellowships until joining CU in 2020. Over his career he has worked on several aspects of theoretical quantum physics with an emphasis on quantum sensing, measurement, light-matter interaction, and quantum computing. In 2016 he was a recipient of an Australian Research Council fellowship known as the “discovery early career researcher award” (DECRA). Prior to that, he held independent postdoctoral fellowships at the Perimeter Institute for Theoretical Physics and the Institute for Quantum Computing.