Microwave Photon Generation and Entanglement for Distributed Quantum Computing
Doctoral thesis, 2024
Distributed Quantum Computing (QC) is a system that interconnects multiple quantum processors through quantum communication channels. It enables scalable and robust quantum computations by leveraging the combined capabilities of each processor. This thesis explores key components of distributed QC, specifically focusing on the generation of propagating microwave photons and the emission of entanglement using superconducting systems. We present a series of experimental and theoretical demonstrations that establish essential foundations for high-fidelity quantum state transfer and remote entanglement generation via propagating microwave photons. First, we demonstrate deterministic quantum state transfer from a superconducting qubit to a propagating microwave mode by encoding the quantum state as a superposition of the vacuum state and the single-photon Fock state. We employ photon shaping techniques to emit photons with time-symmetric amplitude and constant phase, thereby ensuring efficient reabsorption by a receiver. However, photon loss remains the primary loss channel in distributed QC networks. To address this challenge, we further propose and experimentally generate frequency-bin-encoded photonic modes, that can serve as a heralding protocol for detecting photon losses. The protocol is achieved by deterministic encoding of qubit information into two simultaneous photonic modes with different frequencies. By excluding the vacuum as a logical state, frequency-bin-encoded photons enable effective error detection at the receiver processor. Finally, we explore the generation of entangled photonic modes through the continuous driving of a quantum emitter. We demonstrate that the temporally filtered modes, obtained from the two sidebands of the resonance fluorescence spectrum, exhibit entanglement and can be extracted to separate quantum processors. These works serve as foundational building blocks for quantum state transfer and remote entanglement in distributed QC networks, with potential applications in waveguide quantum electrodynamics and scalable quantum architectures.
Microwave quantum optics
Entanglement
Dual-rail photon emission
Heralding protocols
Distributed quantum computing
Superconducting circuits
Frequency-bin encoding
Single-photon source
Single-rail photon emission
Quantum networks
MC2 (Kemivägen 9, 412 58 Göteborg), Kollektorn; Or zoom with the password: 204852
Opponent: Christian Kraglund Andersen, TU Delft, Netherlands
Author
Jiaying Yang
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology
Deterministic generation of shaped single microwave photons using a parametrically driven coupler
Physical Review Applied,;Vol. 20(2023)
Journal article
Jiaying Yang, Ingrid Strandberg, Alejandro Vivas-Viaña, Akshay Gaikwad, Claudia Castillo-Moreno, Anton Frisk Kockum, Muhammad Asad Ullah, Carlos Sánchez Muñoz, Axel Martin Eriksson, and Simone Gasparinetti. Entanglement of photonic modes from a continuously driven two-level system
Jiaying Yang, Maryam Khanahmadi, Ingrid Strandberg, Akshay Gaikwad, Claudia Castillo-Moreno, Anton Frisk Kockum, Muhammad Asad Ullah, Göran Johansson, Axel Martin Eriksson, and Simone Gasparinetti. Deterministic generation of frequency-bin-encoded microwave photons
In the rapidly evolving landscape of quantum technology, the quest for scalable and reliable quantum computing systems is paramount. Distributed Quantum Computing (QC) emerges as a promising solution, interconnecting multiple quantum processors to harness their collective computational power. This modular approach addresses scaling challenges while offering flexibility—malfunctioning subsystems can be replaced or repaired without recreating the entire system, enabling more robust and versatile quantum computations. One of the main challenges for implementing distributed QC is the establishment of low-loss quantum channels between quantum processors, which ideally facilitate deterministic quantum state transfer and the generation of quantum entanglement between processors.
This thesis focuses on two key tasks essential for Distributed QC. The first task involves encoding quantum information from static qubits onto traveling photonic modes. To address the issue of channel loss, we implement dual-rail photonic mode generation, which can serve as an error-detection protocols, enhancing the reliability of quantum information transfer. The second task explores the generation of entangled photonic modes from a continuously and coherently driven static qubit, which holds the potential for distributing entanglement to remote processors or quantum memories.
This thesis is based on superconducting circuits operating in the microwave regime, with potential extensions to other quantum platforms. By leveraging the proposed building blocks, we can implement a distributed QC system in the future, enabling a range of applications. By employing circuit cutting techniques, complex quantum algorithm can be divided into smaller, manageable segments that are efficiently processed on the distributed system. Additionally, incorporating microwave-to-optical transducers enhances the system’s ability to transfer quantum information over long distances. This enables applications such as quantum key distribution and quantum networking, while also advancing the development of practical and scalable quantum technologies.
This thesis focuses on two key tasks essential for Distributed QC. The first task involves encoding quantum information from static qubits onto traveling photonic modes. To address the issue of channel loss, we implement dual-rail photonic mode generation, which can serve as an error-detection protocols, enhancing the reliability of quantum information transfer. The second task explores the generation of entangled photonic modes from a continuously and coherently driven static qubit, which holds the potential for distributing entanglement to remote processors or quantum memories.
This thesis is based on superconducting circuits operating in the microwave regime, with potential extensions to other quantum platforms. By leveraging the proposed building blocks, we can implement a distributed QC system in the future, enabling a range of applications. By employing circuit cutting techniques, complex quantum algorithm can be divided into smaller, manageable segments that are efficiently processed on the distributed system. Additionally, incorporating microwave-to-optical transducers enhances the system’s ability to transfer quantum information over long distances. This enables applications such as quantum key distribution and quantum networking, while also advancing the development of practical and scalable quantum technologies.
Wallenberg Centre for Quantum Technology (WACQT)
Knut and Alice Wallenberg Foundation (KAW 2017.0449, KAW2021.0009, KAW2022.0006), 2018-01-01 -- 2030-03-31.
Areas of Advance
Information and Communication Technology
Subject Categories
Physical Sciences
Infrastructure
Nanofabrication Laboratory
ISBN
978-91-8103-137-9
Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 5595
Publisher
Chalmers
MC2 (Kemivägen 9, 412 58 Göteborg), Kollektorn; Or zoom with the password: 204852
Opponent: Christian Kraglund Andersen, TU Delft, Netherlands