Conveners
Quantum Information & Computing
- Matthias Dietl
Quantum Information & Computing
- Gabriel Araneda
Quantum Information & Computing
- Marco Valentini (Universitรคt Innsbruck)
Quantum Information & Computing
- Edgar Brucke (ETH Zurich)
In the current stage of its evolution, Quantum Information Processing is
following the precedent set by classical computing and generally encodes information in binary form, thus relying on so-called qubits. For many of the systems used to process this quantum information, this is however a rather artificial constraint, limiting the Hilbert space available for computation and introducing...
A proposed scheme for implementing trapped-ion quantum computing encodes qubits in different types of electronic levels where logic gates can be implemented with low cross-talk, know as the omg architecture [1]. One type of qubit this scheme employs is the metastable (m) qubit, which has not been widely studied. We have implemented m qubits in the D$_{5/2}$ manifold of $^{40}$Ca$^+$ and...
Measurement-induced state disturbance is a main challenge in obtaining quantum statistics at multiple time points. We propose a method to extract dynamic information from a quantum system at intermediate time points, namely snapshotting quantum dynamics. In order to do this, we introduce a multi-time quasi-probability distribution (QPD) that correctly recovers probability distributions at...
We propose a new sub-Doppler cooling scheme in trapped ion crystals in Paul traps which utilizes a Sisyphus-like cooling mechanism to simultaneously cool all the motional modes of the crystal.
We use a hollow tweezer, tuned near resonance with the transition from the qubit manifold to a short-lived excited manifold, to generate a state-dependent tweezer potential. This introduces a position...
Building useful quantum computers means making them better as well as bigger. At Oxford Ionics we replace the lasers conventionally used to manipulate ion qubits with electronics integrated directly into trap chips, which allows us to reach very low error rates in a highly scalable architecture.
Our all-electronic architecture combines laser-free gates with local tuning of electric potentials...
Quantum gate teleportation utilises shared entanglement and local operations and classical communication to mediate logical gate operations between qubits that cannot directly interact, making it an essential tool for the modular quantum computing architecture [1]. In this work, we demonstrate the deterministic teleportation of a controlled-Z gate between two ${}^{43}\textrm{Ca}^+$ hyperfine...
A network of bosons evolving among different modes while passing through beam splitters and phase shifters has been applied to demonstrate quantum computational advantage. Such networks have mostly been implemented in optical systems using photons. However, technical bottlenecks exist in photon systems. In particular, photon loss and non-deterministic generation and inefficient detection of...
The aim of this project is to build a quantum computing processor with integrated ion-photon interface. It consists of an ion trap with zones for ion loading, QIP and a zone with an integrated optical cavity for enhanced communication. The electrode structure is designed for dual species operation, ion swapping and ion chain splitting. To achieve highly efficient high-fidelity quantum...
Our project aims at setting up an ion-trap based, high-performance quantum computer, to push the current limits of gate fidelities and SPAM errors. We want to achieve such by using Barium as our qubit platform, which offers some key advantages over its most prominent competitors Calcium and Ytterbium. One example are the laser wavelengths required to interact with Barium, which are suited for...
Trapped $^{137}\textrm{Ba}^+$ ions possess two long-lived hyperfine manifolds in which quantum information can be stored: the ground $S_{1/2}$ level and the metastable $D_{5/2}$ level. The metastable level does not couple to the fluorescence beams, so information stored there is protected during dissipative operations such as cooling, state preparation or readout. This allows for these...
We present the design and industrial fabrication of a micro-penning trap.
To fully harness the potential of trapped ions for applications in quantum information processing, it is necessary to scale to large numbers of ions. By building upon existing technologies in micro-fabrication, surface-electrode traps provide a promising approach for a scalable architecture. However, the conventional...
A trapped ion forms a hybrid system consisting of the electronic spin and bosonic motional modes. The Hamiltonian describing the interaction between laser light and this hybrid system, when containing only commuting terms, leads to simple dynamics. However, the presence of non-commuting terms, either due to spurious off-resonant interactions or deliberate inclusion, leads to complex and rich...
Encoding information redundantly in quantum error correcting (QEC) codes is a way โ perhaps the only way โ to protect quantum information processors from the harmful effects of noise that impede large-scale computation. However, the execution of QEC itself is subject to faults which can transform and spread uncontrollably unless fault-tolerant design principles are applied as well. The...
The presence of noise in quantum system makes the precise and efficient characterization of errors necessary. A myriad of benchmarking and tomography routines have been developed over the years to address this challenge. However, most of these suffer from scalability problems in implementation and the information extracted is frequently lacking in predictive or diagnostic utility. A major...
In trapped-ion quantum computing, quantum logic gates are often performed using lasers. Alternatively, gates can also be driven by microwave fields for which the technology is cheaper and more reliable, making it simpler to scale up. However, due to their centimetre wavelength, microwaves cannot be focused to a small spot size, making it difficult to address an individual ion within a cluster...
Trapped ions have proved to be the leading quantum computing platform, due to their long coherence times and simple reproducibility. The design of modular architectures is also facilitated, which is crucial for a scalable, universal quantum computer. Our blueprint for a trapped-ion based quantum computer outlines operating with global microwave (MW) fields to dress the ground-state hyperfine...
