A versatile magnetometer must deliver a readable response when exposed to targets fields in a wide range of parameters. In this work, we experimentally demonstrate that the combination of a $^{171}\mathrm{Yb}^+$ atomic sensor with adequately trained neural networks enables the characterization of target fields in challenging scenarios. In particular we estimate parameters of radio frequency...
Traditionally, molecules were considered too complicated for coherent quantum control. Recent molecular-ion-trapping developments enabled trapping, ground-state cooling, high-fidelity state detection, precision spectroscopy, coherent manipulation, and atom-molecule entanglement. Nowadays, molecule diversity and the variety of molecular degrees of freedom open new research directions that are...
We have built a microfabricated surface trap with integrated chip capacitors for quantum computation and simulation experiments. The trap features two loading zones at both sides for isotope selection and a central quantum operation region. We fabricate a series of parallel plate capacitors on chip with each capacitance around 800 pF to shunt the pick-up RF noise to the ground. The trap is...
Coherently manipulated crystals of ions in a Penning trap are a promising candidate for near-term quantum simulation of complex many-body phenomena and the search for dark matter using quantum sensing [1]. At the University of Sydney, we developed a Penning trap to perform such experiments with crystals containing hundreds of beryllium ions [2]. This contribution introduces this system and two...
Trapped-ion based quantum computers rely on frequency and phase locked lasers to perform experiments. Conventionally, this requires the use of bulky RF electronics that hinder scalability as well as inject noise into the system. In this poster, I will discuss the performance of a frequency/phase locking PCB that we have designed to allow for a more efficient and compact beat-note...
We designed an ion trap with integrated fiber cavities for enhanced coupling between single ion and photons. We fabricated the fiber electrodes covered with metal except for the light-through region by a series of processes including etching, CO2 laser ablation, lithography, magnetron sputtering, stripping, and electroplating. Its metallic part can be used both to provide the voltage required...
Abstract Advances in research such as quantum information and quantum chemistry require subtle methods for trapping particles (including ions, neutral atoms, molecules, etc.). Here we propose a hybrid ion trapping method by combining a Paul trap with optical tweezers. The trap combines the advances of the deep-potential feature for the Paul trap and the micromotion-free feature for the optical...
Motional modes of trapped ions have been shown to be a useful tool for quantum sensing, making use of time reversal protocols. This application requires the ability to prepare well-defined motional states with high fidelity. Many of these states can be generated from motional ground states without the use of laser fields. We report our results in generating one-mode and two-mode squeezed...
Ultracold trapped ions in linear radiofrequency traps are well-established and highly controllable quantum systems with a variety of applications in fields such as precision spectroscopy, cold chemistry, quantum information and optical clocks. Nanomechanical oscillators are highly sensitive objects for the development and implementation of technologies in miniaturized devices. Their nanoscopic...
In this work we show theoretically and experimentally how to use dark resonances emerging from coherent population trapping (CPT) in a multi-level lambda-type system as local electric field and temperature probes. To do this, we include a third laser to the system to avoid optical pumping effects. We find that the nature of the dark resonances can be either preserved or affected by the...
A dedicated control system is pivotal for sophisticated experiments in atomic, molecular and optical (AMO) physics. In particular, large-scale ion-trap and neutral atom quantum computing will require some of the most complex control systems ever built. These will need to support measurement-heavy workflows, fast feedback with tight latency constraints, and be scalable in hardware and software....
We’ve designed and built a high-pass optical bladetrap, with the ability to achieve NA=0.66 in two laser directions and NA=0.37 in the other two. This bladetrap has excellent performance: the vacuum can reach 7*10^-17 Torr at room temperature, and the Q value of helical can reach 280. Combined with optical and electronic scheme, we demonstrate a low-crosstalk optical double-side addressing...
Single-qubit rotations and a two-qubit entangling gate form a universal set of quantum logic gates[1]. In this work, we realize such a two-qubit computational register that is compatible with the quantum charge-coupled device (QCCD) architecture. Quantum logic operations are implemented using embedded microwave conductors. Single-qubit gates in two-ion crystals are performed by addressing each...
One of the challenges of ion-trap based quantum computers is their scalability. With an increasing number of qubits and parallelization of computation junctions and ion transport become necessary. A surface quantum charged coupled device architecture is a promising approach to tackle this challenge. Storage registers are needed for temporarily storing ions inbetween excecuting individual gate...
Quantum simulation area promising approach for understanding the dynamics governed by quantum field theories in the strong coupling regime. However, a lot of qubits and gates are required due to the presence of bosons in these models. Taking advantage of the available bosonic degrees of freedom in the quantum system can potentially help with this problem. In this talk, we propose a scheme to...
Quantum mechanics has overturned people's traditional cognition, and the superposition contradicts the fact that objects in our daily life are always in a certain state. Leggett and Garg proposed the Leggett-Garg inequality (LGI) to verify the existence of macroscopic superposition states. Classical systems are limited by LGI, while quantum systems may violate LGI. LGI provides an observable...
As the simplest molecules, molecular hydrogen ions (MHIs) are calculable, with ab initio theory reaching uncertainties for the prediction of transition frequencies only a factor of 10 larger than those achieved for the hydrogen atom [1]. They thus offer great potential for the extraction of fundamental constants as well as for tests of QED and search for BSM physics.
We present an overview...
Chip-based trapping technology has emerged as a promising approach for multi-dimensional quantum simulations and entanglement using individually controllable trapped ion qubits arrays. Previous studies have demonstrated successful local control, inter-site coupling, and floquet-engineered couplings in such architectures[1-3]. Here we present the extension of the existing toolbox by introducing...
One of the most formidable challenges of scaling up quantum computers is that of control signal delivery. Today’s small-scale quantum computers typically connect each qubit to one or more separate external signal sources. This approach is not scalable due to the I/O limitations of the qubit chip, necessitating the integration of control electronics. However, it is no small feat to shrink...
The combination of the entangling Mølmer–Sørensen gate and single qubit rotations
is a well-established method to realise a universal set of quantum gates using trapped ions. Implementing this gate scheme using global microwave fields can further the scaling prospects of this quantum computing platform, by reducing the complexity of the laser system required. [1]
Our approach uses current...
The integration of photonic components in surface electrode traps is a promising approach for scalable quantum computing with trapped ions [1].
Integrated photonics enables efficient delivery of laser light to the trap chip. Beams can be tightly focused on the ions, reducing power requirements, and a given configuration of laser fields can be reliably reproduced in different zones of the...
Quantum correlations, both spatial and temporal, are the central pillars of quantum mechanics. Over the last two decades, a big breakthrough in quantum physics is its complex extension to the non-Hermitian realm, and dizzying varieties of novel phenomena and applications beyond the Hermitian frame work have been uncovered. However, unique features of non-Hermitian quantum correlations,...
Using quantum annealing algorithms to solve optimization problems represents a promising path to achieving a practical quantum advantage in the NISQ era. Problems of interest are typically formulated as a quadratic unconstrained binary optimization (QUBO) and then encoded into a spin glass Hamiltonian with two-body spin interactions.
Recently the inclusion of higher-order terms into the...
An attractive proposition to extend the capabilities of quantum information systems is to fully utilise their high-dimensional Hilbert space. The internal electronic structure of trapped atomic ions offers a natural way to encode information not just in a two-level system, but in a high-dimensional qudit instead. One of the challenges of this approach is to achieve high fidelity interactions...
Topological transitions between different types of triply degenerate points are experimentally observed with a trapped ion. Recently, the remarkable discovery of topological semimetals with triply degenerate points in Fermionic systems provides an avenue for exploring new types of quasiparticles beyond quantum field theory. Such triply degenerate points are naturally characterized by high-rank...
Accurately measuring the potential generated by electrode of a Paul trap is of great importance for either precision metrology or quantum computing using ions in a Paul trap. For a rectangular shaped electrode, we find a simple and highly accurate parametric expression of the spatial field distribution. Using this expression, a method based on multi-objective optimization is presented to...
The Mølmer–Sørensen (MS) scheme has facilitated Quantum Simulation of Ising-type ($J_{ij}^x \sigma_x^i \sigma_x^j \;$) interacting-spin-systems, leveraging collective motional-modes of ions. However, only a few experiments explored more complex models, like XY models that can simulate novel many-body systems such as superfluids and spin-liquids. Existing protocols used modified MS schemes...
The integration of qubit control and readout elements into microfabricated surface-electrode ion traps offers potential advantages for scaling to larger trapped-ion systems. We report progress on two efforts in this direction. First, we present measurements of improved trap-integrated superconducting photon detectors for qubit fluorescence readout. The detectors are shielded from the trap rf,...
Remote entanglement using a quantum network has applications in distributed quantum computation, long-range quantum sensing, and secure quantum communication. Trapped ions present unique advantages as the quantum repeater node of a quantum network due to the ability to precisely prepare, control, and manipulate each qubit, perform high fidelity operations between qubits, and maintain...
The nature of dark matter (DM) and its interaction with the Standard Model (SM) is one of the biggest open questions in physics nowadays. Ultralight DM coupling to the SM induces oscillations in fundamental constants that are detectable by comparing clocks with different sensitivities to DM. Vibrational transitions of molecular clocks are more sensitive than electronic transitions of optical...
In the long-term, fault-tolerant (FT) quantum information processing is the central promise to demonstrate a quantum advantage for practical problems. However, in the current era of Noisy-Intermediate Scalable Quantum (NISQ) devices, low distance quantum error-correcting (QEC) codes and quantum error mitigation methods pave the way to today’s quantum reliable hardware. Unlike QEC techniques,...
Optical tweezers offer new opportunities to control and manipulate trapped ions with applications in quantum information processing. Two techniques to implement quantum logic gates have been theoretically developed in our group. These are based on qubit state-dependent potentials delivered by optical tweezers in combination with either electric fields [1], or strong polarization gradients in...
The Strontium ion is an ideal candidate for medium-distance quantum networking due to an atomic transition at 1.1 $\mu$m, a wavelength compatible with existing fiber optic infrastructure. This transition eliminates the need for lossy photon conversion processes, allowing for direct remote entanglement on the kilometer scale. We report on current progress towards ion-photon entanglement in a...
Conical intersections (CIs) are an ever-present phenomenon in chemistry and molecular physics that mark the crossing of energy levels on an adiabatic potential energy surface (PES). Around such intersections, the Born-Oppenheimer approximation breaks down and the coupling between electronic and nuclear coordinates becomes important. Thus, efficiently simulating the dynamics in the vicinity...
Quantum network is of great importance to the development of quantum communication, quantum computation and quantum metrology. With photon interference, separate quantum nodes can be entangled to build large-scale quantum information processor. However, its scaling up is facing with the challenge of quantum memory decoherence from photonic interfaces. To avoid disturbance, in trapped ion...
Trapped ions constitute one of the most promising systems for implementing quantum computing and networking. For large-scale ion-trap-based quantum computers and networks, it is critical to have two types of qubit: one for computation and storage, and another for auxiliary operations such as qubit detection, sympathetic cooling and entanglement generation through photon links. Previously, it...
Being a prospective platform for quantum computing and metrology, Coulomb
crystals of ultracold trapped ions currently reach sizes of hundreds of
individual particles. Such systems require high level of control over their
motional temperature in order to account for the second-order Doppler shift in
atomic clocks and implement high-fidelity entangling gates in quantum
computers. However,...
Forming antiprotonic atoms and their investigation is one of the goals of the AEgIS project at CERN. An intermediate stage of such an experiment is preparing a set of negative, atomic ions, co-trapped with antiprotons in a Penning trap. Such anions must be delivered in a single pulse, which requires an efficient, well-controlled, pulsed source of the ions.
Since attachment of electrons to...
We theoretically examine the effects of spontaneous emission at high magnetic fields for multi-qubit entangling operations on large ion crystals, and compare different gate types, laser beam detunings and polarizations, magnetic field strengths, and ion species. We show that the current configuration in the Penning trap at NIST is approximately ideal for light-shift (LS) gates in $^9$Be$^+$...
We summarize Quantinuum’s progress in research and development of surface-electrode ion traps for QCCD quantum computing architectures. This includes additional information about the racetrack trap in the commercially available H2 computer as well as design and experimental progress towards 2D ion trap grids planned for next-generation commercial computers.
We present here an experiment focusing on the extension of sympathetic cooling techniques to the unfavourable case of large mass ratios between the two ionic species involved and for ions injected from outside the trap. This study is essential to the success of ambitious projects such as the GBAR (Gravitational Behaviour of Antihydrogen at Rest) project aiming to study the free fall of a...
Molecular ions exhibit a rich internal structure attributed to their vibrational and rotational degrees of freedom. However, at room temperature, the rotational energy level populations are widely distributed due to black body thermalization, and the numerous decay pathways make direct laser cooling of molecules challenging at best, and impossible at worst. Therefore, we aim to demonstrate a...
Trapped-ion quantum sensors have become highly sensitive tools for the search of physics beyond the Standard Model. We present our recent measurements on the test of local Lorentz -invariance (LLI) with a single Yb+ ion [1] and isotope shift measurements for the search of the fifth force mediated by a potential dark matter boson [2,3].
In the attempt to unify all fundamental forces at the...
The dipole-phonon interaction (DPI) between the permanent dipole of a diatomic molecular ion and the secular oscillation of the ion chain manifests as a Jaynes-Cummings-type interaction. When combined with quantum logic, this interaction can enable state preparation and measurement of quantum information encoded within a molecular ion [1,2]. Here, we report on our progress toward observing...
Single-ion optical atomic clocks have reached fractional uncertainties of 1 part in $10^{-18}$ [1], but reaching this level of uncertainty requires long averaging times. Using $n$ uncorrelated ions, the same uncertainty could be obtained $n$ times quicker. If these $n$ ions could be placed in an entangled state however, speed-ups beyond this standard quantum limit are in principle possible...
Trapped ions have proved to be a promising way of realising a large-scale quantum computer. They allow for simple reproducibility and modular architectures 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 manifold of 171Yb+ ions [1]. By...
Ultrafast spin-phonon entanglement based on SDKs provides an approach to realize fast entangling gates with intrinsic robustness and scalability for trapped ion quantum computing. Such SDKs so far have been implemented on a nanosecond timescale by off-resonant Raman transitions where each laser pulse is split into a sequence of perturbation pulses with carefully designed temporal...
HITRAP is a facility for deceleration of large bunches of highly charged ions (HCI) produced online by the GSI accelerator. It consists of an ion transport beamline from the accelerator, an IH-structure and an RFQ for deceleration down to several keV/q, as well as a Penning-Malmberg trap for ion cooling down to sub-eV energies.
The linear deceleration stages reduce the ion energy from $4...
Electron-atom collision experiments are widely used to study the structure of bombarded objects. The experimentally determined scattering amplitudes associated with measured cross-sections complement the data obtained in spectroscopic studies. The measurement usually involves the bombardment of the target with a monochromatic electron beam and the detection of non-scattered or scattered...
To realize a useful quantum computer based on trapped ions, scaling the number of ions is an important requirement. However, scaling up to several hundreds or thousands of ions while maintaining sufficient qubit fidelity implies complex trap designs that can only be achieved by first-class industrial manufacturing. Fabrication in a productive fab offers a precise process control as well as...
In order to scale trapped ion quantum computing from small lab experiments to industrial quantum computers, large ion traps will need to contain integrated electronics. Integrated electronics minimizes the number of voltages passed into the cryostat as the number of feed-throughs is limited. This reduces the complexity as well as the heat load on the cryostat. Here, I want to present the...
