Ion traps are a promising platform to host a quantum information processor. However, on the road to producing a functional quantum computer, scaling up to hundreds of ions is a challenge.
The established usage of 1D arrays of ion qubits limits connectivity to low ion numbers, thus restricting the quantum advantage.
In this work we develop an ion trap architecture where independent ion...
When considering the design of a trapped-ion quantum computer, a key aspect that emerges is the required operating temperature. Indeed, several advantages can be gained by operating trapped ion systems at low temperatures [1]. For example, cryogenic ion-trap systems boast of enhanced vacuum conditions, leading to increased ion lifetime; lower motional heating rates, increasing both ion...
Trapped ions are promising qubit systems for quantum information processing due to their long coherence times and high gate fidelities. Current scalable trap design efforts rely on 2D surface traps, which are challenged by shallow trap depths and sensitivity to electric field noise. We built a cryogenic system aimed at efficient, iterative prototyping of scalable 3D-printed ion traps. These...
Trapped ions are a leading platform for quantum computing due to their long coherence time, high level of control over internal and external degrees of freedom, and the natural full connectivity between qubits. Single and multi-qubit operations have been performed with high fidelity (>99.9%), enabling the demonstration of small universal quantum computers (approx. 10 atoms). However, scaling...
Sinara is an open-source, open-hardware control system specifically created for quantum applications that is currently operational in numerous global laboratories. Its design is based on ribbon cable connections linking a controller with peripheral modules. This seemingly uncomplicated and economical method, however, has raised concerns about system reliability, thermal management, and...
Direct implementation of multi-qubit gates with three or more qubits circumvents decomposition into two-qubit operations, effectively reducing the required depth of quantum circuits. Using the inherent all-to-all coupling in a trapped ion quantum computer, we experimentally realize classical Toffoli and perceptron gates with three microwave-driven hyperfine qubits using 171Yb+ ions. The...
We report the numerical simulation, fabrication process, and characterization of a segmented-blade trap with biasing rods [1, 2]. Our homemade trap consists of two radio frequency blades, dc blades with ten separate electrodes, and two biasing rods for compensating the ions' micromotion. We explore the effect of the rods on the trap potential and the influence of trap misalignment. The trap...
Microwave driven operations offer a scalable approach to trapped ion quantum computing, with cheap and reliable components; stable phase and amplitude control; and potentially higher fidelity gates. However, whilst laser beams can be focussed onto individual ions, the centimeter-wavelength of microwaves requires alternate techniques to address individual qubits. Here, we experimentally...
In a recent demonstration of the quantum charge coupled device (QCCD) trapped ion architecture [1], circuit time is dominated by cooling operations. Some motional modes of a multi-ion crystal are cooled inefficiently due to the geometry of the cooling lasers and the coupling of the mode to the sympathetic coolant ion species, requiring as much as 1 ms to cool to the ground state, whereas...
Manipulation of single trapped molecules on the quantum level has gained notable interest in recent years. Their complex energy-level structure with rotational and vibrational degrees of freedom provides a plethora of transitions with various properties but also presents challenges toward molecular state initialisation, manipulation and readout. Building on the methods known for trapped atomic...
Highly charged ions (HCI) offer promising candidate species for searches of physics beyond the Standard Model and next-generation optical atomic clocks. In the CryPTEx-SC experiment, we store HCIs in a cryogenic linear Paul trap that simultaneously functions as a superconducting radio-frequency resonator filtering the trap drive [1].
The HCIs are produced in a compact electron beam ion trap...
Superradiant lasers are a promising path towards realising a narrow-linewidth, high-precision and high-bandwidth active frequency reference [1]. They shift the phase memory from the optical cavity, which is subject to technical and thermal vibration noise, to an ultra-narrow optical atomic transition of an ensemble of cold atoms trapped inside the cavity. Our previous demonstration of pulsed...
The motional degree of freedom of a trapped ion system has been studied as a conveyor of quantum information in the context of continuous variable quantum computing (CVQC) [1,2]. Theoretical and experimental studies concerning quantum information processing with the motional degrees of freedom include phonon sampling [3,4], and encoded qubits [5]. In this work, we experimentally create the...
We present our experimental progress on the control and application of the vibrational modes with a cryogenic trapped Calcium ions system. We implement a segmented four-blade Paul trap in a closed-cycle 4 K cryostat, achieving a heating rate of 8 phonon/s at a trap frequency of 1.1 MHz. We utilize this setup and entangle two vibration modes with reservoir engineering, and obtain a stable...
Detecting and minimizing the micromotion in an ion trap system is crucial for precise control of the quantum states and suppression of heating. For this purpose, several methods have been reported, such as measuring fluorescence amplitude at the rf frequency, optimizing the optical sideband spectrum, minimizing ion displacement while alternating between different trap depths, and employing...
The currently most accurate frequency standards based on optical transitions have reached fractional systematic uncertainties on the order of $1 \times 10^{-18}$, enabling sensitive tests of fundamental physics [1]. The Stark shift induced by room temperature blackbody radiation (BBR) in many cases causes the largest shift from the unperturbed transition frequency and limits the systematic...
Digital quantum simulation is an exciting near-term application of NISQ quantum devices. The re-programmable digital approach allows them to emulate a wide range of interesting materials, such as topological matter or large molecules, that have proven too complex to understand using classical physics and standard computation. Digital simulation combines the tool-set of quantum information with...
Electronic control methods, where quantum gates are implemented without lasers, hold great potential for trapped-ion quantum computing due to their low fundamental errors and the ease of scalability. In this work, we demonstrate a new electronic control method, where addressed single-qubit rotations are implemented by localized AC electric fields, generated by trap electrodes. We demonstrate...
Trapped Rydberg ions combine the advantages of ion trapping and tunable and long-range Rydberg interactions. They enable entangling operations over longer distances and are great candidates for performing fast and scalable entangling gates.
Working with Rydberg ions is promising but also challenging. It is so mostly due to the need to address transitions with UV lasers and relatively frequent...
We present the fabrication of trapped ion microchips integrated with the key features required to realise a scalable architecture for a modular microwave trapped-ion quantum computer. In our approach for ion trap quantum computing [1], high currents of up to 15 A generate large local magnetic field gradients at the ion position which, together with global microwave and RF fields, enable the...
The inherent quantum nature of single trapped ions makes them promising candidates for the experimental realization of qubits, the fundamental building blocks of quantum computers. In order to harvest the potential that trapped ions posses, it is necessary to not only have precise control over an ion's quantum state but also over its motional state. Doppler cooling is commonly deployed to...
Chip-based ion traps are a versatile platform for quantum technologies. Our established ion traps for optical clocks enable controlling systematic frequency uncertainties at the 10^-19 level [1, 2]. Currently, we are developing ion traps with integrated optics. Integrated optics improve the robustness against vibrations, make the traps scalable to large numbers of ions, and help to compactify...
Trapped ions are one of the leading candidates for performing quantum simulation, computation, and precision measurements. Entanglement in simulation experiments plays a crucial role in generating exciting quantum many-body states and distinguishes these experimental systems from their classical counterparts. Investigating entanglement in many body systems is extremely valuable to reveal...
Interference underpins some of the most unusual and impactful properties of both the classical and quantum worlds, from the highest powered lasers down to the level of single photons. However, with regards to light-matter coupling, neither the usual classical nor quantum descriptions of interference can sufficiently explain why some states of light couple to matter while others do not. In this...
Sensors based on the wave nature of a massive particle are expected to be one of the next generations’ high-performance sensing technologies. Atoms and ions are ideal for such use since they give us the capability to control their quantum states using optical means precisely. A Laser-cooled ion in an ion trap is an important platform for quantum sensing due to its ideally isolated condition...
Networked architectures provide a route to freely-scalable quantum computation with trapped ions, with entanglement between ions in remote nodes mediated by the coherent production, interference and projective measurement of single photons. Two-node networks have provided proof-of-principle demonstrations but have been limited in the rate of entanglement achieved, and many further hurdles...
We present our preliminary findings regarding the measurement of the isotope shift in the $4s\textrm{ }^2S_{1/2} \rightarrow 3d\textrm{ }^2D_{5/2}$ transition within pairs of even isotopes of Ca$^+$. We perform the measurement by co-trapping the isotope pairs in a single well produced by a micro-fabricated segmented ion trap. Our method showcases a significant advancement in accuracy,...
Radium-225 (nuclear spin 1/2) is a particularly appealing candidate for optical clocks and testing fundamental symmetries due to its accessible electronic structure and heavy, octupole deformed nucleus. We demonstrated the first laser cooling of short-lived $^{224}$Ra$^+$ (3.6 day half-life) and $^{225}$Ra$^+$ (15 day half-life) ions which are loaded into linear Paul traps by a two-step...
The Antimatter Experiment: Gravity, Interferometry, Spectroscopy (AEGIS) at CERN utilizes cold antiproton beams from the Antimatter Decelerator to study gravitational effects on antihydrogen beams. The pulsed production of Rydberg excited antihydrogen is achieved through a charge exchange reaction between laser-excited Rydberg positronium and cold antiprotons. This same technique is now being...
At the proton g-factor experiment in Mainz we have recently succeeded in sympathetically cooling a single proton by laser-cooled 9Be+ ions stored in a separate Penning trap. Here, the coupling between both ion species is mediated by image currents induced in a common RLC circuit. Uniquely, our setup combines laser cooling and fluorescence detection of the 9Be+ ions with image current detection...
Entangling gates are an essential buliding block of any quantum processor, ideally working at high speeds in a in a robust and scaleable manner. Microwave-driven trapped-ion gates present promising features in terms of scalability and stability of the driving field. Experimentally, limited fidelity values are mostly attributed to the use of magnetic field sensitive states, which make qubits...
Registers of different qubit types, where one qubit type is insensitive to the other's light fields, are a promising avenue for scaling the quantum information processing capabilities of trapped-ion systems [1]. This approach mitigates scattering errors and allows for advanced qubit control schemes by enabling partial projective measurements, mid-circuit measurements, and in-sequence...
Trapped ions are a leading platform for quantum computers, with their high level of programmability and lack of idle decoherence mechanisms. Here, we present progress on building a state-of-the-art quantum computer with full control of up to 32 $^{171}$Yb$^+$ ion qubits on a Sandia Phoenix ion trap chip. We measure the heating rate as a function of trap axial frequency and manage sources of...
We study two parallel ion chains in a surface-electrode trap with an RF electrode configuration creating a double-well potential in order to establish a nanofriction model. One of the nanofriction models is Frenkel-Kontorova (FK) model which has close similarities to two parallel ion chains. The FK model is composed of a chain of classical particles which are harmonically coupled to the...
A system of confined charged particles undergoes crystallization at sufficiently low temperature, forming self-organized structures in which each particle is spatially localized. However, when particles in a two-dimensional plane are confined by an isotropic potential, there is no preferential orientation of the crystal, and thermal fluctuations lead to the delocalization of particles in...
Long chains of trapped ions are a leading platform for quantum information processing, but their control suffers from spectral crowding and excess motional heating when chains grow too long. One proposal to access larger Hilbert spaces and thus more computational power is to entangle ions in separate traps via photonic interconnects. Previous demonstrations have used 0.6 NA objectives to...
Trapped ion chains are a promising architecture for the development of quantum computers and quantum simulators owing to their high connectivity, high-fidelity gate operations, and long coherence times. Scaling up to many qubits is challenging as adding more ions to each chain increases its susceptibility to electric fields, slows down the gate operation and increases errors due to thermal...
While prime candidates as nodes in long-distance quantum networks, trapped ions do not typically emit photons at telecommunications wavelengths. Quantum frequency conversion (QFC) allows trapped ions to connect with other nodes of a long-distance quantum network by frequency downconverting ion-emitted visible and near-IR photons to telecommunications wavelengths [1-3]. Polarization-preserving...
A detector moving with relativistic accelerated trajectory would experience Unruh effect and raise both detector excitation and particle creation in the accelerated frame, despite being in a vacuum in the rest frame. We simulate such an effect in the case of the detector oscillating in a cavity with a laser-controlled trapped ion. The simulation could be extended to superposed quantum...
Ion traps are a promising candidate for a scalable quantum computer [1]. A major challenge is the integration of qubit control into the device.
With the microwave near-field approach [2], qubit control realized by microwave conductors that are integrated into the ion trap naturally scale with the trap itself.
However, the microwave signal generation currently takes place outside of the...
A cornerstone of all quantum technology is the reliable characterization of the underlying building blocks, in particular the prepared quantum states. The standard approach for this task is to perform local Pauli measurements and from that estimate the quantities of interest. As the system size grows, however, the number of measurement bases to consider grows exponentially. We show that this...
Linear strings of trapped ions in radio-frequency traps are a well-established platform for quantum simulation of magnetism. However, linear strings feature some drawbacks, among them difficulties in scaling the system size beyond 50 ions or the inability to investigate spin models in more than one dimension where many exotic quantum phenomena are expected to manifest. Here we present our...
Penning traps are high-precision tools for mass spectrometry and spectroscopy experiments. Two such experiments based on Penning traps at the GSI Helmholtz Centre for Heavy Ion Research are: ARTEMIS and SHIPTRAP. The ARTEMIS Penning trap experiment aims to measure the magnetic moment of an electron bound to heavy, highly charged ions using the laser-microwave double-resonance spectroscopy...
A quantum repeater node is presented based on trapped ions that act as single-photon emitters, quantum memories, and an elementary quantum processor. The node’s ability to establish entanglement across two 25-km-long optical fibers independently, then to swap that entanglement efficiently to extend it over both fibers, is demonstrated. The resultant entanglement is established between...
Quantum simulations stand out as a particularly promising application of quantum computers. The noisy intermediate-scale quantum (NISQ) devices pave the way for the development of fault-tolerant quantum computers. However, the presence of noise and decoherence in current noisy quantum devices necessitates the use of hybrid quantum algorithms based on low-depth circuits to achieve promising...
The NEXT experiment [1] is currently being built at the AGOR facility in Groningen. NEXT aims to study Neutron-rich EXotic, heavy nuclei around N=126 and in the transfermium region which are produced in multinucleon Transfer reactions. Precision mass spectrometry and decay spectroscopy will be used to characterize these nuclei.
The target-like transfer products are pre-separated from the...
The success of trapped molecular ion precision spectroscopy in eEDM searches motivates the extension of the platform to more complicated polyatomic species to test the Standard Model (SM) and search for new physics.
The prediction that weak force parity violation (PV) breaks the symmetry between the left and right-handed chiral molecules has eluded detection for decades in a field dominated...
Here, we report on the development of a large-scale quantum simulator with programmable individual control of more than 50 $^{171}\rm{Yb}^+\;$ ions in a segmented `blade trap’ system. The trap allows high NA optical access from four directions and will include high fidelity and low crosstalk in-situ state measurement and reset of individual ions [1]. Our custom monolithic optical breadboards...
We report our plans and progress towards implementing a cavity quantum electrodynamics system with Barium ions. With Barium ions’ strong S-P dipole transition at 493 nm, we can expect much stronger ion-cavity coupling than achievable with infrared transitions in Barium as well as in other atomic species. This can be exploited for high-fidelity light-atom entanglement generation and state...
Comparisons of fundamental properties of matter and antimatter provide stringent tests of CPT symmetry [1]. Throughout the past years, measurements of proton and antiproton g-factors in Penning traps have been carried out with outstanding precision, setting new constraints on CPT violating effects of the SME [2,3]. However, these experiments rely on time consuming particle cooling and state...
Large scale quantum computing is subject to extensive research and the ideal platform for general purpose quantum computers has yet to be found. Trapped ions as qubits excel in terms of gate fidelity and coherence times but so far systems have mostly been limited to only a small number of qubits. Our system is designed to support a linear chain of up to 50 ions which can be individually...
Highly charged ions (HCI) feature an enhanced sensitivity to fundamental physics while many systematic effects from external perturbations are highly suppressed [1]. They are therefore excellent systems to test our understanding of nature and to realize novel high-accuracy optical atomic clocks.
Recently, quantum logic spectroscopy (QLS) of a fine-structure transition in a medium-light HCI...
Exotic atoms, formed by substituting one or more of their constituents—electrons, protons or neutrons—with others of the same electric charge, have played a pivotal role in studying the fundamental interactions in nature. Antiprotonic exotic atoms, containing at the same time matter and antimatter can be used to test matter-antimatter asymmetries, one of the unresolved questions in modern...
Modern trapped-ion experiments frequently utilize hundred(s) of trap electrodes and ten(s) of laser beams which have to be operated in a precise and synchronous manner. Akkodis is developing the required control electronic system. Within the IQUAN project [1] we design a modular, scalable electronic system consisting of precision pulse generators and real-time control logic. Within the ATIQ...
