Ion Trap Research Articles

Trapping Ions to Enhance High-Field Energy Harvesting Performance by Filling Polar Macromolecular Dielectrics.

In the quest for sustainable and renewable energy sources, researchers and engineers have explored innovative technologies to harvest energy from various environmental sources. Dielectric elastomer generators (DEGs) with high energy harvesting performance have been proven to be promising energy collectors, but achieving a high dielectric constant (ε') and low electrical conductivity (EC) under high electric fields of dielectric elastomer (DE) simultaneously is a struggle, which poses significant challenges. In this study, high-content carboxyl group-grafted liquid polybutadiene (HCPB) is synthesized and then adopted as an organic dielectric filler to blend and cocross-link with a butadiene rubber (BR) matrix to prepare DE composites with high energy harvesting performance. The introduction of carboxyl groups enhances polarization while trapping free Al3+ in the matrix, which revolutionarily achieves a significant increase in ε' under extremely low EC. Ultimately, the contradiction between increased ε' and decreased EC under high electric fields is reconciled, resulting in a 30 HCPB/BR composite with high energy density (w = 91.9 mJ/cm3) and fine power conversion efficiency (PCE = 24.1%). This advancement paves the way for the development of HCPB/BR composite-based DEGs with enhanced ε' and energy harvesting performance.

Achieving Electron Capture Dissociation in the Radio Frequency Linear Ion Trap without the Assistance of a Magnetic Field─A Simulation Study.

It is extremely difficult to inject a low-energy electron beam into a conventional radiofrequency (RF) linear ion trap for electron capture dissociation (ECD) without using a magnetic field to focus the electrons. In this study, the dynamic process of electrons in an RF field during their injection and transmission through a linear ion trap was simulated to determine the range of the RF phase where the electrons can be decelerated to meet the energy requirement for ECD. The ECD time window was expanded by applying a time-dependent compensation voltage to the cathode. The relationship between the cathode voltage and the phase of the RF voltage was determined. The ECD time window was increased to 49.4% of the total RF cycle after applying a compensation voltage. Between the phases of RF voltage of 0 and 0.975 π, at least 98.7% of electrons can be injected into the ECD reaction zone, and 94% of them had an energy less than 3 eV. The range of electron energy can also easily be shifted upward to enable hot electron capture dissociation.

Superconducting surface trap chips for microwave-driven trapped ions

Microwave-driven trapped ion logic gates offer a promising avenue for advancing beyond laser-based logic operations. In future microwave-based operations, however, the joule heat produced by large microwave currents flowing through narrow microwave electrodes would potentially hinder improvements in gate speed and fidelity. Moreover, scalability, particularly in cryogenic trapped ion systems, is impeded by the excessive joule heat. To address these challenges, we present a novel approach: superconducting surface trap chips that integrate high-Q microwave resonators with large current capacities. Utilizing sub-ampere microwave currents in superconducting Nb resonators, we generate substantial magnetic field gradients with significantly reduced losses compared to conventional metal chips. By harnessing the high Q factors of superconducting resonators, we propose a power-efficient two-qubit gate scheme capable of achieving a sub-milliwatt external microwave input power at a gate Rabi frequency of 1 kHz.

Bottom-up Histone Post-translational Modification Analysis using Liquid Chromatography, Trapped Ion Mobility Spectrometry, and Tandem Mass Spectrometry.

The amino acid position within a histone sequence and the chemical nature of post-translational modifications (PTMs) are essential for elucidating the "Histone Code". Previous work has shown that PTMs induce specific biological responses and are good candidates as biomarkers for diagnostics. Here, we evaluate the analytical advantages of trapped ion mobility (TIMS) with parallel accumulation-serial fragmentation (PASEF) and tandem mass spectrometry (MS/MS) for bottom-up proteomics of model cancer cells. The study also considered the use of nanoliquid chromatography (LC) and traditional methods: LC-TIMS-PASEF-ToF MS/MS vs nLC-TIMS-PASEF-ToF MS/MS vs nLC-MS/MS. The addition of TIMS and PASEF-MS/MS increased the number of detected peptides due to the added separation dimension. All three methods showed high reproducibility and low RSD in the MS domain (<5 ppm). While the LC, nLC and TIMS separations showed small RSD across samples, the accurate mobility (1/K0) measurements (<0.6% RSD) increased the confidence of peptide assignments. Trends were observed in the retention time and mobility concerning the number and type of PTMs (e.g., ac, me1-3) and their corresponding unmodified, propionylated peptide that aided in peptide assignment. Mobility separation permitted the annotation of coeluting structural and positional isomers and compared with nLC-MS/MS showed several advantages due to reduced chemical noise.

Quantum repeater node with free-space coupled trapped ions

Quantum repeater node with free-space coupled trapped ions

Gas-Phase Structures of Fucosylated Oligosaccharides: Alkali Metal and Halogen Influences.

Fucosylated carbohydrate antigens play critical roles in physiology and pathology with function linked to their structural details. However, the separation and structural characterization of isomeric fucosylated epitopes remain challenging analytically. Here, we report for the first time the influence of alkali metal cations (Li+, Na+, K+, Rb+, and Cs+) and halogen anions (Cl-, Br-, and I-) on the gas-phase conformational landscapes of common fucosylated trisaccharides (Lewis A, X, and H types 1 and 2) and tetrasaccharides (Lewis B and Y) using trapped ion mobility spectrometry coupled to mass spectrometry and theoretical calculations. Inspection of the mobility profiles of individual standards showed a dependence on the number of mobility bands with the oligosaccharide and the alkali metal and halogen; collision cross sections are reported for all of the observed species. Results showed that trisaccharides (Lewis A, X, and H types 1 and 2) can be best mobility resolved in the positive mode using the [M + Li]+ molecular ion form (baseline resolution r ≈ 2.88 between Lewis X and A); tetrasaccharides can be best mobility resolved in the negative mode using the [M + I]- molecular ion form (baseline separation r ≈ 1.35 between Lewis B and Y). The correlation between the number of oligosaccharide conformers as a function of the molecular ion adduct was studied using density functional theory. Theoretical calculations revealed that smaller cations can form more stable structures based on the number of coordinations, while larger cations induced greater oligosaccharide reorganizations; candidate structures are proposed to better understand the gas-phase oligosaccharide rearrangement trends. Inspection of the candidate structures suggests that the interplay between ion size/charge density and molecular structure dictated the conformational preferences and, consequently, the number of mobility bands and the mobility separation across isomers. This work provides a fundamental understanding of the gas-phase structural dynamics of fucosylated oligosaccharides and their interaction with alkali metals and halogens.

AC Zeeman effect in microfabricated surface traps.

Quantum processors and atomic clocks based on trapped ions often utilize an ion's hyperfine transition as the qubit state or frequency reference, respectively. These states are a good choice because they are insensitive in first order to magnetic field fluctuations, leading to long coherence times and stable frequency splittings. In trapped ions, however, these states are still subject to the second order AC Zeeman effect due to the necessary presence of an oscillating magnetic field used to confine the ions in a Paul trap configuration. Here, we measure the frequency shift of the 2S1/2 hyperfine transition of a 171Yb+ ion caused by the radio frequency (RF) electromagnetic field used to create confinement in several microfabricated surface trap designs. By comparing different trap designs, we show that two key design modifications significantly reduce the AC Zeeman effect experienced by the ion: (1) an RF ground layer routed directly below the entire RF electrode, and (2) a symmetric RF electrode. Both of these changes lead to better cancellation of the AC magnetic field and, thus, overall reduced frequency shifts due to the AC Zeeman effect and reduced variation across the device. These improvements enable a more homogeneous environment for quantum computing and can reduce errors for precision applications such as atomic clocks.

The Peregrine Ion Trap Mass Spectrometer (PITMS) Investigation Development and Preflight Planning

The Peregrine Ion Trap Mass Spectrometer (PITMS) is a mass spectrometer instrument that operated during the Astrobotic Peregrine Mission-1 as part of the NASA Commercial Lunar Payload Services initiative. This paper describes the instrument and investigation design, development, and planning conducted by the PITMS team, consisting of a successful partnership between NASA Goddard Space Flight Center (GSFC), The Open University, NASA, and ESA. PITMS was designed to measure the abundance and temporal variability of volatile species in the near-surface lunar exosphere from a landed platform on the lunar surface. The PITMS instrument consisted of a European Space Agency–provided Exospheric Mass Spectrometer (including sensor, electronics, controller, and power supply boards) and a GSFC wrapper that provided structural elements, thermal control, and a deployable dust cover. PITMS was designed to operate as a passive sampler, where ambient gases would enter PITMS through an aperture, diffuse around the mass analyzer cavity, become ionized by electron impact and trapped in an RF field, and then sequentially be released to a detector to build a mass spectrum. PITMS was capable of measuring species with a mass-to-charge ratio (m/z) from 10 to 150 Da, with a mass resolution of approximately 0.5 amu. The PITMS science investigation was planned to be operated by GSFC with an international team of scientists. Though the mission did not achieve its lunar landing, information about the PITMS instrument and planning is provided to be able to understand and effectively use data that will be forthcoming from the investigation.

LC-MS based strategy for chemical profiling and quantification of dispensing granules of Ginkgo biloba seeds

Ginkgo biloba seeds have been used as a traditional Chinese medicine for hundreds of years to treat diseases such as cervicitis, cough, asthma and other lung diseases. As a novel form, the dispensing granules (GSDG) of Ginkgo biloba seeds have been widely employed in clinic. However, its chemical profiling is not yet clear, which has restricted in-depth research in many fields.In this study, a high performance liquid chromatography coupled with quardrupole time-of-flight mass spectrometry method was used for the component characteration with the help of accurate molecular weights, fragmentation pathways, reported data, literatures and even some reference standards. Furthermore, in multiple-reaction monitoring mode, a high performance liquid chromatography coupled with quadrupole linear ion trap mass spectrometry method was developed and applied for simultaneous determination of the bioactive phytochemicals.As a result, a total of 56 components in GSDG were identified including 12 amino acids, 9 organic acids, 6 nucleosides and nucleobases, 6 flavonoids, 5 vitamins, 5 terpenoid lactones, 4 carbohydrates and 9 other compounds As for quantitative analysis, glutamic acid, asparatic acid, histidine, ginkgolide A, ginkgolide B, ginkgolide C, ginkgolide J, eucomic acid, N-(N-glucopyranosyl)-indoleacetylaspartate and N-(N-glucopyranosyl)-indoleacetylglutamate were selected as the analytes for quanlity marker of GSDG. After necessary validation tests, the developed quantitative method was successfully put into use for 10 batches of GSDG. In all batches, N-(N-glucopyranosyl)-indoleacetylaspartate was the richest phytochemical with the amount of 17.3–25.7 mg/g while ginkgolide J (0.0197–0.0335 mg/g) was determined to be the poorest.The study is supposed to exhibit a comprehensive chemical profiling and to provide some strong basis for preparation technology, quality control and even for action mechanism of GSDG, this novel form of Chinese medicine.

Zn–Al with NO2− as a corrosion inhibitor epoxy-coated carbon steel under artificial atmospheric conditions

This study evaluated Zn–Al–NO2− layered double hydroxide as a corrosion inhibitor in a high-thickness epoxy resin coating (200 µm). The layered double hydroxide was tested in a NaCl solution, using electrochemical impedance spectroscopy. The formed oxides were analysed by X-ray diffraction and energy dispersive X-ray spectroscopy. The corrosion resistance of the epoxy coating (with and without layered double hydroxide) was analysed by electrochemical impedance spectroscopy after exposure to a NaCl solution, salt spray, or a weather-O-meter chamber in a simulated atmospheric environment. The electrochemical impedance spectroscopy measurements for the free layered double hydroxide in a NaCl solution revealed that layered double hydroxide prompted the formation of a compact, protective, and insoluble oxide layer on the carbon steel surface. The Cl− permeability through the epoxy resin film was 5.88 times lower for the film containing layered double hydroxide than for the control. The layered double hydroxide was added to the epoxy coating at a 5 wt-% to evaluate the behaviour of the coating in aggressive environments. The entry of aggressive ions was controlled by the ability of the layered double hydroxide to capture them and release the corrosion inhibitors. Thus, the layered double hydroxide worked as a trap for these aggressive ions and enhanced the performance of the coating. Therefore, a layered double hydroxide addition could benefit a high-thickness coating exposed to an aggressive environment and UV radiation.

Demonstration of Capture, Cooling, Tagging, and Spectroscopic Characterization of UV Photoproduct Ions in a Cryogenic Ion Trap: Application to 266 nm Photofragment Ions from Rhodamine 6G.

We demonstrate a method to determine the structures of the primary photodissociation products from a cryogenically cooled parent ion. In this approach, a target ion is cooled by a pulse of buffer gas and tagged in a 20 K Paul trap. The cold ion is then photodissociated by pulsed (∼5 ns) UV laser excitation, and the ionic products are trapped, cooled, and tagged by introduction of a second buffer gas pulse in the same trap. The tagged fragments are then ejected into a triple focusing, UV/vis/IR time-of-flight photofragmentation mass spectrometer which yields vibrational and electronic spectra of the mass-selected photofragments. These methods are demonstrated by application to the 266 nm photodissociation of the Rhodamine 6G cation to yield the R575 fragment ion based on loss of ethene as well as to a weaker secondary fragment arising from loss of m/z 43.

Hardware requirements for trapped-ion-based verifiable blind quantum computing with a measurement-only client

Abstract In blind quantum computing (BQC), a user with a simple client device can perform a quantum computation on a remote quantum server such that the server cannot gain knowledge about the computation. Here, we numerically investigate hardware requirements for verifiable BQC using an ion trap as server and a distant measurement-only client. While the client has no direct access to quantum-computing resources, it can remotely execute quantum programs on the server by measuring photons emitted by the trapped ion. We introduce a numerical model for trapped-ion quantum devices in NetSquid, a discrete-event simulator for quantum networks. Using this, we determine the minimal hardware requirements on a per-parameter basis to perform the verifiable BQC protocol. We benchmark these for a five-qubit linear graph state, with which any single-qubit rotation can be performed, where client and server are separated by 50 km. Current state-of-the-art ion traps satisfy the minimal requirements on a per-parameter basis, but all current imperfections combined make it impossible to perform the blind computation securely over 50 km using existing technology. Using a genetic algorithm, we determine the set of hardware parameters that minimises the total improvements required, finding directions along which to improve hardware to reach our threshold error probability that would enable experimental demonstration. In this way, we lay a path for the near-term experimental progress required to realise the implementation of verifiable BQC over a 50 km distance.

Optimization and Detection of Freshness Biomarkers of Atlantic Salmon Subjected to Different Vacuum Packaging Conditions during Storage at 0 °C by Metabolomics and Molecular Docking.

The freshness of Atlantic salmon is influenced mainly by tissue metabolism, which in turn is affected by storage time and conditions. The alterations in taste profiles and nutritional values of salmon when packaged using vacuum methods have not been fully understood, and the factors contributing to these changes require further research. In this work, the extraction method for flavor nutrients from salmon was optimized via the Plackett-Burman (PB) test. A sensitive and rapid targeted metabolomics method for the simultaneous determination of 34 nutrients was successfully established via ultra-performance liquid chromatography-triple quadrupole/linear ion trap composite mass spectrometry (UHPLC-QTRAP/MS), and various nutritional compositions during storage at 0 °C under different vacuum conditions (0 kPa or -90 kPa) for 4 and 8 days were analyzed. Results showed that storage time had a significant effect on salmon metabolism. The total amino acids decreased by 62.95% and 65.89% at 0 kPa and -90 kPa, respectively. Notably, a marked reduction in histidine after 8 days at -90 kPa may have diminished bitterness, while decreased levels of umami-tasting amino acids like glutamine and aspartic acid affected the overall flavor profile. Overall, the packaging conditions at 0 °C and 0 kPa were more suitable for the preservation of most nutrients in salmon. Pathway enrichment analysis revealed that the reduction in substances was mainly related to the alanine, aspartate, and glutamate metabolism pathways. Alanine, inosine, and histidine, whose levels changed significantly, can bind to the typical umami taste receptor TIR1/TIR3 and can be biomarkers to monitor and determine the freshness or spoilage of salmon after 4-8 days of storage. This study revealed the changes in small-molecule nutrients in salmon during storage under different packaging conditions, which provides a reference for the packaging preservation technology of fresh salmon and new ideas for the evaluation of salmon quality and determination of freshness.

Optimized Surface Ion Trap Design for Tight Confinement and Separation of Ion Chains

Qubit systems based on trapped ultracold ions win one of the leading positions in the quantum computing field, demonstrating quantum algorithms with the highest complexity to date. Surface Paul traps for ion confinement open the opportunity to scale quantum processors to hundreds of qubits and enable high-connectivity manipulations on ions. To fabricate such a system with certain characteristics, the special design of a surface electrode structure is required. The depth of the trapping potential, the stability parameter, the secular frequency and the distance between an ion and the trap surface should be optimized for better performance. Here, we present the optimized design of a relatively simple surface trap that allows several important high-fidelity primitives: tight ion confinement, laser cooling, and wide optical access. The suggested trap design also allows us to perform an important basic operation, namely, splitting an ion chain into two parts.

Identifying biomarkers for nasopharyngeal carcinoma diagnosis and chemoradiotherapy response using serum endogenous small molecules profiling

Changes in metabolic characteristics are important features of tumor progression and prognosis, including nasopharyngeal carcinoma (NPC). Identifying serum metabolites as potential diagnostic and chemoradiotherapy response biomarkers for NPC is therefore crucial. In this study, ultra-performance liquid chromatography coupled with linear ion trap quadrupole orbitrap high-resolution mass spectrometry (UPLC-LTQ-Orbitrap MS) was used to analyze metabolic variations among controls, NPC patients, and NPC patients undergoing chemoradiotherapy (CRT). Univariate and multivariate analyses revealed seven differential metabolites between the control and NPC groups and eleven metabolites between the CRT and NPC groups. Five common metabolites, gluconic acid, palmitic acid, LysoPC (15:0/0:0), stearic acid, and LysoPC (20:2(11Z,14Z)/0:0), were consistently altered across groups. Notably, the first four metabolites were adjusted closer to normal after chemoradiotherapy, while this change is not reflected at LysoPC (20:2(11Z,14Z)/0:0). These common metabolites were enriched in five pathways. These findings underscore the importance of serum metabolite profiling in NPC diagnosis and treatment response assessment and offer a promising foundation for further clinical research.

Electronic and vibrational spectroscopy of benzonitrile cation for astrochemical consideration.

The electronic and vibrational spectra of benzonitrile cation, C6H5CN+ (BZN+), in the gas phase at low temperatures are reported. Measurements were carried out using a cryogenic ion trapping apparatus. The mid-infrared spectrum shows a strong CN stretch at 2130 ± 1 cm-1 (4.694 ± 0.002 µm). The electronic spectrum is reported in the range 5040-5750Å. This covers the forbidden B2B2 ← X2B1 and allowed C2B1 ← X2B1 transitions. The spectrum is dominated by a broad absorption feature at wavelengths shorter than 5250Å, with the strongest absorption located at 5140Å. Experimental data are complemented with quantum chemical calculations carried out at the density functional theory and extended multi-configurational quasi-degenerate perturbation theory level. The spectroscopic results are discussed in the context of astronomical observations in the infrared and visible.

Low cross-talk optical addressing of trapped-ion qubits using a novel integrated photonic chip

Individual optical addressing in chains of trapped atomic ions requires the generation of many small, closely spaced beams with low cross-talk. Furthermore, implementing parallel operations necessitates phase, frequency, and amplitude control of each individual beam. Here, we present a scalable method for achieving all of these capabilities using a high-performance integrated photonic chip coupled to a network of optical fibre components. The chip design results in very low cross-talk between neighbouring channels even at the micrometre-scale spacing by implementing a very high refractive index contrast between the channel core and cladding. Furthermore, the photonic chip manufacturing procedure is highly flexible, allowing for the creation of devices with an arbitrary number of channels as well as non-uniform channel spacing at the chip output. We present the system used to integrate the chip within our ion trap apparatus and characterise the performance of the full individual addressing setup using a single trapped ion as a light-field sensor. Our measurements showed intensity cross-talk below ~10–3 across the chip, with minimum observed cross-talk as low as ~10–5.

A novel UV-curable composite coating with superior anti-corrosion and mechanical properties

The UV curing method is free from volatile organic compounds (VOC) and exhibits high curing efficiency. However, pore flaws and inadequate mechanical qualities after cure greatly hinder their utilization in metal anti-corrosion. Herein, layered double hydroxides (LDH) supported by molybdic acid and cerium ions were synthesized in situ on the sericite (SC) surface, enhancing the shielding, corrosion inhibition, resin compatibility, and cross-linking density of the coating. Compared with carbon steel immersed in a 3.5 wt% NaCl solution, the incorporation of SC/KH560@LDH reduced the corrosion current density (Icorr) from 2.001 × 10−5 A/cm2 to 7.883 × 10−6 A/cm2. Moreover, the low-frequency impedance of the UV-SC/KH560@LDH coating remained high at 1.939 × 1010 Ω·cm2 after 70 days of immersion in a 3.5 wt% NaCl solution. The excellent corrosion resistance of UV-SC/KH560@LDH can be attributed to the barrier properties of the filler, the chloride ion trapping, and the passivation effect. Furthermore, the UV-curable alkyd resin used in this work formed a chemical bond with the metal substrate, enhancing the mechanical properties of the coating. The adhesion strength of the UV-SC/KH560@LDH was measured at 11.50 MPa. The thickness loss (21.3 μm) of the UV-SC/KH560@LDH were minimal after 5000 cycles of wear. A new research concept for preparing the UV-SC/KH560@LDH with superior anti-corrosion and mechanical properties for carbon steel plate surfaces has been proposed to meet the demands of practical applications.

Amorphous Hydrated Tungsten Oxides with Enhanced Pseudocapacitive Contribution for Aqueous Zinc‐Ion Electrochromic Energy Storage

AbstractTungsten oxides suffer from sluggish ion diffusion kinetics, limited ion storage capacity, and inadequate stability within the aqueous zinc ion electrolyte, thereby constraining their applicability in electrochromic energy storage devices (EESDs). Here, the amorphous hydrated tungsten oxide films with large optical modulation, fast response speed, large capacity, and high cycling stability are reported, enabled by tuning the contents of structural water and adjusting the pH value of aqueous zinc ion electrolyte. The enhancement of the electrochromic and ion storage performance is mainly due to the introduction of structural water which triggers pseudocapacitive behavior dominated by surface redox reaction, resulting in high electrochemical activity and fast electrochemical kinetics. Meanwhile, the relatively low pH value ensures the chemical stability of the hydrated tungsten oxide film, in synergy with surface redox that avoids ion trapping, leading to extraordinary cycling stability of up to 13000 cycles, marking the state‐of‐the‐art stability for tungsten oxide‐based materials in aqueous electrolyte. Based on the hydrated tungsten oxide films, high‐capacity and stable large‐size EESDs are constructed with the capability of visually monitoring energy status, recovering energy, and regulating light. This work provides a simple yet effective strategy for enhancing the performance of tungsten oxide‐based aqueous zinc ion EESDs.

Digital Ion Trap Isolation and Mass Analysis of Macromolecular Analytes with Multiply Charged Ion Attachment.

Multiply charged ions produced by electrospray ionization (ESI) of heterogeneous mixtures of macromolecular analytes under native conditions are typically confined to relatively narrow ranges of mass-to-charge (m/z) ratio, often with extensive overlap. This scenario makes charge and mass assignments extremely challenging, particularly when individual charge states are unresolved. An ion/ion reaction strategy involving multiply charged ion attachment (MIA) to the mixture components in a narrow range of m/z can facilitate charge and mass assignment. In MIA operation, multiply charged reagent ions are attached to the analyte ions of opposite polarity to provide large m/z displacements resulting from both large changes in mass and charge. However, charge reduction of the high m/z ions initially generated under native ESI conditions requires the ability to isolate high m/z ions and to analyze even higher m/z product ions. Digital ion trap (DIT) operation offers means for both high m/z ion isolation and high m/z mass analysis, in addition to providing conditions for the reaction of oppositely charged ions. The feasibility of conducting MIA experiments in a DIT that takes advantage of high m/z ion operation is demonstrated here using a tandem 2D-3D DIT instrument. Proof-of-concept MIA experiments with cations derived from β-galactosidase using the 20- charge state of human serum immunoglobulin G (IgG, ∼149 kDa) as the reagent anion are described. MIA experiments involving mixtures of ions derived from the E. coli. ribosome are also described. For example, three components in a mixture of 70S particles (>2.2 MDa) were resolved and assigned with masses and charges following an MIA experiment involving the 20- charge state of human serum IgG.