Scalable arrays of micro-Penning traps for quantum computing and simulation

We propose the use of 2-dimensional Penning trap arrays as a scalable platform for quantum simulation and quantum computing with trapped atomic ions. This approach involves placing arrays of micro-structured electrodes defining static electric quadrupole sites in a magnetic field, with single ions trapped at each site and coupled to neighbors via the Coulomb interaction. We solve for the normal modes of ion motion in such arrays, and derive a generalized multi-ion invariance theorem for stable motion even in the presence of trap imperfections. We use these techniques to investigate the feasibility of quantum simulation and quantum computation in fixed ion lattices. In homogeneous arrays, we show that sufficiently dense arrays are achievable, with axial, magnetron and cyclotron motions exhibiting inter-ion dipolar coupling with rates significantly higher than expected decoherence. With the addition of laser fields these can realize tunable-range interacting spin Hamiltonians. We also show how local control of potentials allows isolation of small numbers of ions in a fixed array and can be used to implement high fidelity gates. The use of static trapping fields means that our approach is not limited by power requirements as system size increases, removing a major challenge for scaling which is present in standard radio-frequency traps. Thus the architecture and methods provided here appear to open a path for trapped-ion quantum computing to reach fault-tolerant scale devices.Comment: 21 pages, 10 figures Changes include adding section IX (Implementation Example) and substantially rewriting section X (Scaling

Sphagnum abundance and photosynthetic capacity show rapid short-term recovery following managed burning

Background: Prescribed burning in peatlands is controversial due to concerns over damage to their ecological functioning, particularly regarding their key genus Sphagnum. However, empirical evidence is scarce. Aims: The aim of the article is to quantify Sphagnum recovery following prescribed burns. Methods: We completed nine fires at a raised bog in Scotland, achieving a range of fire severities by simulating drought in some plots. We measured Sphagnum cover and chlorophyll fluorescence Fv/Fm ratio (an estimate of photosynthetic capacity) up to 36 months post-fire. Results: Cover of dominant Sphagnum capillifolium was similar in unburnt and burnt plots, likely due to its high moisture content which prevented combustion. Burning decreased S. capillifolium Fv/Fm 5 months after fire from 0.67 in unburnt plots to 0.44 in low fire severity plots and 0.24 in higher fire severity (drought) plots. After 22 months, Fv/Fm in burnt plots showed a healthy photosynthetic capacity of 0.76 and no differences between severity treatments. Other Sphagnum species showed similar post-fire recovery though their low overall abundance precluded formal statistical analysis. Conclusions: S. capillifolium is resilient to low–moderate fire severities and the same may be true for a number of other species. This suggests that carefully applied managed burning can be compatible with the conservation of peatland ecosystem function

Do Not Be an Invisible Library!

The role of the library keeps changing, particularly with the development of new education models and technologies. User behaviors are changing, too, and libraries need to adapt and use different approaches in providing library services and access to content. Digital tools make online content search easy, but sometimes the value the library brings gets lost, even though it is the library that purchases, sets up, and maintains that online access to content. The most recent Ithaka US Faculty Survey highlights this misunderstanding—a large percentage of scientists feel that “because faculty have easy access to academic content online, the role librarians play at their institution is becoming much less important”. What new value-added benefits and services can libraries consider to help teaching faculty and researchers, or increase the prestige of their school? As higher education explores online and MOOC opportunities, how can libraries provide support? Rick Burke, Executive Director of SCELC, shares challenges he hears from libraries. As the e-resource marketplace has evolved, the need has grown for tools to help libraries promote and manage access to those resources, while providing a means to assert the library\u27s role in making those resources available. He will discuss SCELC\u27s experiences in bringing these tools to the consortial marketplace. Matt Goldner, Product and Technology Advocate of OCLC, will give insights on the changing relationship between library and school community, as well as OCLC\u27s initiatives to help libraries adjust to the new landscapes. Franny Lee, Co-Founder of SIPX, will discuss the research conducted by the Stanford Intellectual Property Exchange on measuring the content access benefits that the library relationship brings to higher education students, as well as SIPX\u27s experiences translating requests and feedback from libraries into opportunities for copyright education and user interface design that makes the library\u27s role visible. Glenn Johnson-Grau, Head of Collection Development at Loyola Marymount University, will discuss the effect of diminishing visibility on academic libraries as users decreasingly associate the library with the physical collection and the new opportunities that open when we strengthen campus relationships and reassert our value in the academic mission of our organizations

Magnetic quadrupole moment of 175^{175}Lu and parity-violating polarization degree of levels in 175^{175}LuOH+^+

The calculation of the parity-violating polarizations in the external electric field, which are associated with the electron electric dipole moment ($e$EDM) and magnetic quadrupole moment (MQM) of the $^{175}$Lu nucleus, as well as the determination of the rovibrational structure for the $^{175}$LuOH$^+$ cation, is performed. Beyond the bending of the molecule, the slight effect of the stretching of the distance between Lu and OH is taken into account. This study is required for the preparation of the experiment and for the extraction of the $e$EDM and MQM values of $^{175}$Lu from future measurements.Comment: arXiv admin note: text overlap with arXiv:2211.0211

Laser-induced fluorescence studies of HfF+ produced by autoionization

Autoionization of Rydberg states of HfF, prepared using the optical-optical double resonance (OODR) technique, holds promise to create HfF+ in a particular Zeeman level of a rovibronic state for an electron electric dipole moment (eEDM) search. We characterize a vibronic band of Rydberg HfF at 54 cm-1 above the lowest ionization threshold and directly probe the state of the ions formed from this vibronic band by performing laser-induced fluorescence (LIF) on the ions. The Rydberg HfF molecules show a propensity to decay into only a few ion rotational states of a given parity and are found to preserve their orientation qualitatively upon autoionization. We show empirically that we can create 30% of the total ion yield in a particular |J+,M+> state and present a simplified model describing autoionization from a given Rydberg state that assumes no angular dynamics.Comment: 8 pages, 5 figure

Precision Spectroscopy of Polarized Molecules in an Ion Trap

Polar molecules are desirable systems for quantum simulations and cold chemistry. Molecular ions are easily trapped, but a bias electric field applied to polarize them tends to accelerate them out of the trap. We present a general solution to this issue by rotating the bias field slowly enough for the molecular polarization axis to follow but rapidly enough for the ions to stay trapped. We demonstrate Ramsey spectroscopy between Stark-Zeeman sublevels in 180Hf19F+ with a coherence time of 100 ms. Frequency shifts arising from well-controlled topological (Berry) phases are used to determine magnetic g-factors. The rotating-bias-field technique may enable using trapped polar molecules for precision measurement and quantum information science, including the search for an electron electric dipole moment.Comment: Accepted to Scienc

T,P\mathcal{T,P}-odd effects in the LuOH+^+ cation

The LuOH$^+$ cation is a promising system to search for manifestations of time reversal and spatial parity violation effects. Such effects in LuOH$^+$ induced by the electron electric dipole moment $e$EDM and the scalar-pseudoscalar interaction of the nucleus with electrons, characterized by $k_s$ constant, in LuOH$^+$ are studied. The enhancement factors, polarization in the external electric field, hyperfine interaction, rovibrational structure are calculated. The study is required for the experiment preparation and extraction of the eEDM and ks values from experimental data