## Q-SEnSE

1. M. F. J. Fox , B. M. Zwickl, and H. J. Lewandowski, "Preparing for the quantum revolution: What is the role of higher education?", Physical Review Physics Education Research 16, 020131 (2020), DOI: 10.1103/PhysRevPhysEducRes.16.02013
Quantum sensing, quantum networking and communication, and quantum computing have attracted significant attention recently, as these quantum technologies could offer significant advantages over existing technologies. In order to accelerate the commercialization of these quantum technologies, the workforce must be equipped with the necessary skills. Through a qualitative study of the quantum industry, we describe types of activities being carried out in the quantum industry, profile types of jobs that exist, and describe skills valued across the quantum industry and in each type of job. Current routes into the quantum industry are detailed, profiling the current role of higher education in training a quantum workforce.
2. C. J. Kennedy, E. Oelker, J. M. Robinson, T. Bothwell, D. Kedar, W. R. Milner, G. E. Marti, A. Derevianko, and J. Ye, "Precision Metrology Meets Cosmology: Improved Constraints on on Ultralight Dark Matter from Atom-Cavity Frequency Comparisons", Phys. Rev. Lett. 125, 201302 (2020), DOI 10.1103/PhysRevLett.125.201302
We used three well-established quantum measurement techniques to set new limits on how strongly very low-mass candidates for hypothesized, but so far unobserved, "dark matter" interact with the atoms of regular matter familiar from the world around us. By using cross-comparisons of three measurement techniques, with their different sensitivities to different fundamental constants of Nature, we set tight limits on the properties of one hypothesized type of dark matter and suggest how to expand similar dark matter searches to higher mass. The success of this approach reinforces the trend of using optical light (in or near the visible range) instead of the traditional microwaves to measure time most accurately.
3. K. Matsuda, L. De Marco, J-R. Li, W.G. Tobias, G. Valtolina, G. Quéméner, J. Ye, "Resonant collisional shielding of reactive molecules using electric fields", Science, Vol. 370, Issue 6522, pp. 1324-1327 DOI 10.1126/science.abe737
Ultracold gases of molecules offer a promising platform for new explorations in quantum science, but there's a catch: molecules can undergo rapid chemical reactions, severely limiting how long we can observe the interacting quantum system. In this work, we demonstrated a general method to "shield" molecules from chemical reactions by turning on an external electric field. At a particular electric field strength (the "shielding field"), our potassium-rubidium molecules strongly repelled each other at short distances, and as a result, the rate of chemical reactions was highly suppressed. Once shielded from chemical reactions, the molecules survived for ten times longer than at zero electric field, providing an excellent starting point for future experiments.
4. S. Kelly, A. M. Rey, and J. Marino, "Effect of active photons on dynamical frustration in cavity QED", Physical Review Letters 126, 133603 (2021), 10.1103/PhysRevLett.126.133603
We studied the far-from-equilibrium dynamical regimes of a many-body spin-boson model with disordered couplings relevant for cavity QED and trapped ion experiments. Our study illustrated the resilience of glassy-like dynamics in the presence of active photonic degrees of freedom, suggesting that disordered quantum many-body systems with resonant photons or phonons can display a rich diagram of nonequilibrium responses, with near future applications for quantum information science.
5. R. J. Lewis-Swan, D. Barberena, J. R. K. Cline, D. Young, J.K. Thompson, and A. M. Rey, "Cavity-QED quantum simulator of dynamical phases of a BCS superconductor", Phys. Rev. Lett. 126, 173601 (2021), DOI 10.1103/PhysRevLett.126.173601
In a BCS superconductor electrons can overcome their electrostatic repulsion and manage to attract each other forming Cooper pairs. Superconductivity can naturally emerge by slowly modifying the temperature or pressure of special type of materials. However, it has been predicted that superconductivity can also emerge dynamically by abruptly changing the parameters of the system. So far only indirect evidence of these out-of-equilibrium phases exists in recent pump-probe THz experiments. This work proposes a feasible way for the direct observation of dynamical superconductivity in a cavity QED setting where instead of Cooper pairs it is proposed to use atoms with two internal levels interacting via the exchange of photons in an optical cavity. This work demonstrates how the versatility and robustness of a cavity-QED platform not only allows for the exhaustive study of the entire BCS phase diagram, but also enables experiments to study new dynamical phases in regimes inaccessible in real materials
6. T. Bilitewski, L. De Marco, J. Li, K. Matsuda, W. Tobias, G. Valtolina, J. Ye, and A. M. Rey, "Dynamical generation of spin squeezing in ultra-cold dipolar molecules", Phys. Rev. Lett. 126, 113401 (2021). DOI 10.1103/PhysRevLett.126.113401
Creating a quantum gas of dipolar molecules brings new opportunities to explore exotic quantum phenomena. Exploring long-range interactions among molecules confined in reduced spatial dimensions, quantum correlations between rotations of individual molecules can be established, according to the theory model constructed on a realistic experimental platform. This correlation can be used to enhance metrological capabilities for field sensing
7. M. Mamaev, I. Kimchi, R. Nandkishore, and A.M. Rey, "Tunable spin model generation in spin-orbital coupled fermions in optical lattices", Physical Review Research 3, 013178 (2021). DOI 10.1103/PhysRevResearch.3.013178
We study the dynamical behavior of ultracold fermionic atoms loaded into an optical lattice under the presence of an effective magnetic flux, induced by spin-orbit-coupled laser driving. At half-filling, the resulting system can emulate a variety of iconic spin-1/2 models such as an Ising model, an XY model, a generic XXZ model with arbitrary anisotropy, or a collective one-axis twisting model. The validity of these different spin models is examined across the parameter space of flux and driving strength. In addition, there is a parameter regime where the system exhibits chiral, persistent features in the long-time dynamics. We explore these properties and discuss the role played by the system's symmetries. We also discuss experimentally viable implementations.
8. A. Chu, J. Will, J. Arlt, C. Klempt, and A. M. Rey, "Simulation of XXZ Spin Models using Sideband Transitions in Trapped Bosonic Gases", Physical Review Letters 125, 240504 (2020). DOI 10.1103/PhysRevLett.125.240504
We theoretically propose and experimentally demonstrate the use of motional sidebands in a trapped ensemble of ^{87}Rb atoms to engineer tunable long-range XXZ spin models. We benchmark our simulator by probing a ferromagnetic to paramagnetic dynamical phase transition in the Lipkin-Meshkov-Glick model, a collective XXZ model plus additional transverse and longitudinal fields, via Rabi spectroscopy. We experimentally reconstruct the boundary between the dynamical phases, which is in good agreement with mean-field theoretical predictions. Our work introduces new possibilities in quantum simulation of anisotropic spin-spin interactions and quantum metrology enhanced by many-body entanglement.
9. R. J. Lewis-Swan, S.R. Muleady, and A. M. Rey, "Detecting out-of-time-order correlations via quasiadiabatic echoes as a tool to reveal quantum coherence in equilibrium quantum phase transitions", Physical Review Letters 125, 240605 (2020). DOI 10.1103/PhysRevLett.125.240605
We propose a new dynamical method to connect equilibrium quantum phase transitions and quantum coherence using out-of-time-order correlations (OTOCs). Adopting the iconic Lipkin-Meshkov-Glick and transverse-field Ising models as illustrative examples, we show that an abrupt change in coherence and entanglement of the ground state across a quantum phase transition is observable in the spectrum of multiple quantum coherence intensities, which are a special type of OTOC. We also develop a robust protocol to obtain the relevant OTOCs using quasi-adiabatic quenches through the ground state phase diagram. Our scheme allows for the detection of OTOCs without time reversal of coherent dynamics, making it applicable and important for a broad range of current experiments where time reversal cannot be achieved by inverting the sign of the underlying Hamiltonian.
10. M. H. Muñoz-Arias, P. Poggi, and I. Deustch, “Nonlinear dynamics and quantum chaos of a family of kicked p-spin models”, Phys. Rev. E 103, 052212 (2021). DOI 10.1103/PhysRevE.103.052212
We introduce kicked p-spin models describing a family of transverse Ising-like models for an ensemble of spin-1/2 particles with all-to-all p-body interaction terms occurring periodically in time as delta-kicks. This is the natural generalization of the well-studied quantum kicked top (p=2) [Haake, Kuś, and Scharf, Z. Phys. B 65, 381 (1987)]. We fully characterize the classical nonlinear dynamics of these models, including the transition to global Hamiltonian chaos. The classical analysis allows us to build a classification for this family of models, distinguishing between p = 2 and p > 2, and between models with odd and even p's. Quantum chaos in these models is characterized in both kinematic and dynamic signatures. For the latter, we show numerically that the growth rate of the out-of-time-order correlator is dictated by the classical Lyapunov exponent. Finally, we argue that the classification of these models constructed in the classical system applies to the quantum system as well.
11. R.J. Fasano, Y.J. Chen, W.F. McGrew, W.J. Brand, R.W. Fox, and A.D. Ludlow, "Characterization and Suppression of Background Light Shifts in an Optical Lattice Clock", Phys. Rev. Applied 15, 044016, DOI 10.1103/PhysRevApplied.15.044016
Experiments involving optical traps often require careful control of the ac Stark shifts induced by strong confining light fields. By carefully balancing light shifts between two atomic states of interest, optical traps at the magic wavelength have been especially effective at suppressing deleterious effects stemming from such shifts. Highlighting the power of this technique, optical clocks today exploit Lamb-Dicke confinement in magic-wavelength optical traps, in some cases realizing shift cancelation at the ten parts per billion level. Theory and empirical measurements can be used at varying levels of precision to determine the magic wavelength where shift cancelation occurs. However, lasers exhibit background spectra from amplified spontaneous emission or other lasing modes that can easily contaminate measurement of the magic wavelength and its reproducibility in other experiments or conditions. Indeed, residual light shifts from laser background have plagued optical lattice clock measurements for years. In this work, we develop a simple theoretical model allowing prediction of light shifts from measured background spectra. We demonstrate good agreement between this model and measurements of the background light shift from an amplified diode laser in a Yb optical lattice clock. Additionally, we model and experimentally characterize the filtering effect of a volume Bragg grating bandpass filter, demonstrating that application of the filter can reduce background light shifts from amplified spontaneous emission well below the $10^{−18}$ fractional clock frequency level. This demonstration is corroborated by direct clock comparisons between a filtered amplified diode laser and a filtered titanium:sapphire laser.
12. R. Lewis-Swan, S. R. Muleady, D. Barberena, J. J. Bollinger, and A. M. Rey, "Characterizing the dynamical phase diagram of the Dicke model via classical and quantum probes", Phys. Rev. Res. 3, L022020 (2021), DOI 10.1103/PhysRevResearch.3.L022020
We theoretically study the dynamical phase diagram of the Dicke model in both classical and quantum limits using large, experimentally relevant system sizes. Our analysis elucidates that the model features dynamical critical points that are strongly influenced by features of chaos and emergent integrability in the model. Moreover, our numerical calculations demonstrate that mean-field features of the dynamics remain valid in the exact quantum dynamics, but we also find that in regimes where quantum effects dominate signatures of the dynamical phases and chaos can persist in purely quantum metrics such as entanglement and correlations. Our predictions can be verified in current quantum simulators of the Dicke model including arrays of trapped ions.
13. A. Cidrim, P. Orioli, C. Sanner, R. B. Hutson, J. Ye, R. Bachelard, and A. M. Rey, "Dipole-dipole frequency shifts in multilevel atoms", Phys. Rev. Lett 127, 013401 (2021), DOI 10.1103/PhysRevLett.127.013401
Dipole-dipole interactions lead to frequency shifts that are expected to limit the performance of next-generation atomic clocks. In this work, we compute dipolar frequency shifts accounting for the intrinsic atomic multilevel structure in standard Ramsey spectroscopy. When interrogating the transitions featuring the smallest Clebsch-Gordan coefficients, we find that a simplified two-level treatment becomes inappropriate, even in the presence of large Zeeman shifts. For these cases, we show a net suppression of dipolar frequency shifts and the emergence of dominant nonclassical effects for experimentally relevant parameters. Our findings are pertinent to current generations of optical lattice and optical tweezer clocks, opening a way to further increase their current accuracy, and thus their potential to probe fundamental and many-body physics.
14. C. D. Marciniak, T. Feldker, I. Pogorelov, R. Kaubruegger, D. V. Vasilyev, R. van Bijnen, P. Schindler, P. Zoller, R. Blatt, T. Monz, "Optimal metrology with variational quantum circuits on trapped ions", Preprint: https://arxiv.org/abs/2107.01860
Cold atoms and ions exhibit unparalleled performance in frequency metrology epitomized in the atomic clock. More recently, such atomic systems have been used to implement programmable quantum computers and simulators with highest reported operational fidelities across platforms. Their strength in metrology and quantum information processing offers the opportunity to utilize tailored, programmable entanglement generation to approach the optimal quantum sensor' compatible with quantum mechanics. Here we report quantum enhancement in metrology beyond squeezing through low-depth, variational quantum circuits searching for optimal input states and measurement operators in a trapped ion platform. We perform entanglement-enhanced Ramsey interferometry finding optimal parameters for variational quantum circuits using a Bayesian approach to stochastic phase estimation tailored to the sensor platform capabilities and finite dynamic range of the interferometer. We verify the performance by both directly using theory predictions of optimal parameters, and performing online quantum-classical feedback optimization to self-calibrate' the variational parameters. In both cases we find that variational circuits outperform classical and direct spin squeezing strategies under realistic noise and imperfections. With 26 ions we achieve 2.02(8) dB of metrological gain over classical interferometers.
15. C. Hughes, D. Finke, D.-A. German, C. Merzbacher, P. M. Vora, and H. J. Lewandowski, "Assessing the Needs of the Quantum Industry", Preprint: arxiv.org/abs/2109.03601
Quantum information science and technology (QIST) has progressed significantly in the last decade, such that it is no longer solely in the domain of research labs, but is now beginning to be developed for, and applied in, industrial applications and products. With the emergence of this new quantum industry, a new workforce trained in QIST skills and knowledge is needed. To help support education and training of this workforce, universities and colleges require knowledge of the type of jobs available for their students and what skills and degrees are most relevant for those new jobs. Additionally, students need to know how to tailor their degrees to best align with the current needs of the quantum industry. We report on the results from a survey of 57 companies in the quantum industry, with the goal of elucidating the jobs, skills, and degrees that are relevant for this new workforce. We find a range of job opportunities from highly specific jobs, such as quantum algorithm developer and error correction scientist, to broader jobs categories within the business, software, and hardware sectors. These broader jobs require a range of skills, most of which are not quantum related. Further, except for the highly specific jobs, companies that responded to the survey are looking for a range of degree levels to fill these new positions, from bachelors to masters to PhDs. With this knowledge, students, instructors, and university administrators can make informed decisions about how to address the challenge of increasing the future quantum workforce.
16. B. Li, J. Bartos, Y. Xie, and S-W Huang, "Time-magnified photon counting with 550-fs resolution", Optica 8, 1109 (2021) DOI 10.1364/OPTICA.420816
The authors demonstrate a quantum temporal magnifier that enables femtosecond time-resolved photon counting with close-to-unity efficiency for the first time. The new technology can benefit many research fields such as fluorescence lifetime microscopy, time-of-flight imaging, light-in-flight imaging, time-gated Raman spectroscopy, and computational diffuse optical tomography.
17. D. T. C. Allcock, W. C. Campbell, J. Chiaverini, I. L. Chuang, E. R. Hudson, I. D. Moore, A. Ransford, C. Roman, J. M. Sage, and D. J. Wineland, "Blueprint for trapped ion quantum computing with metastable states", arxiv.org/abs/2109.01272
Quantum computers, much like their classical counterparts, will likely benefit from flexible qubit encodings that can be matched to different tasks. For trapped ion quantum processors, a common way to access multiple encodings is to use multiple, co-trapped atomic species. Here, we outline an alternative approach that allows flexible encoding capabilities in single-species systems through the use of long-lived metastable states as an effective, programmable second species. We describe the set of additional trapped ion primitives needed to enable this protocol and show that they are compatible with large-scale systems that are already in operation.
18. K. W. Lehnert, "Quantum enhanced metrology in the search for fundamental physical phenomena", to appear in "Quantum Information Machines; Lecture Notes of the Les Houches Summer School 2019", M. Devoret, B. Huard, and I. Pop editors, arXiv:2110.04912
These notes summarize lectures given at the 2019 Les Houches summer school on Quantum Information Machines. They describe and review an application of quantum metrology concepts to searches for ultralight dark matter. In particular, for ultralight dark matter that couples as a weak classical force to a laboratory harmonic oscillator, quantum squeezing benefits experiments in which the mass of the dark matter particle is unknown. This benefit is present even if the oscillatory dark matter signal is much more coherent than the harmonic oscillator that it couples to, as is the case for microwave frequency searches for dark matter axion particles.
19. K. Wurtz, B. M. Brubaker, Y. Jiang, E. P. Ruddy, D. A. Palken, and K. W. Lehnert, "A cavity entanglement and state swapping method to accelerate the search for axion dark matter", arXiv:2107.04147
In cavity-based axion dark matter detectors, quantum noise remains a primary barrier to achieving the scan rate necessary for a comprehensive search of axion parameter space. Here we introduce a method of scan rate enhancement in which an axion-sensitive cavity is coupled to an auxiliary resonant circuit through simultaneous two-mode squeezing (entangling) and state swapping interactions. We show analytically that when combined, these interactions can amplify an axion signal before it becomes polluted by vacuum noise introduced by measurement. This internal amplification yields a wider bandwidth of axion sensitivity, increasing the rate at which the detector can search through frequency space. With interaction rates predicted by circuit simulations of this system, we show that this technique can increase the scan rate up to 15-fold relative to the scan rate of a detector limited by vacuum noise.
20. K. Gilmore, M. Affolter, R. J. Lewis-Swan, D. Barberena, E. Jordan, A. M. Rey, and J. J. Bollinger, "Quantum-enhanced sensing of displacements and electric fields with two-dimensional trapped-ion crystals", Science 373(6555), 673–678. (2021), DOI 10.1126/science.abi5226
Fully controllable ultracold atomic systems are creating opportunities for quantum sensing, yet demonstrating a quantum advantage in useful applications by harnessing entanglement remains a challenging task. Here, we realize a many-body quantum-enhanced sensor to detect displacements and electric fields using a crystal of ~150 trapped ions. The center-of-mass vibrational mode of the crystal serves as a high-Q mechanical oscillator, and the collective electronic spin serves as the measurement device. By entangling the oscillator and collective spin and controlling the coherent dynamics via a many-body echo, a displacement is mapped into a spin rotation while avoiding quantum back-action and thermal noise. We achieve a sensitivity to displacements of 8.8 ± 0.4 decibels below the standard quantum limit and a sensitivity for measuring electric fields of 240 ± 10 nanovolts per meter in 1 second. Feasible improvements should enable the use of trapped ions in searches for dark matter.
21. R. Kaubruegger, P. Silvi, C. Kokail, R. van Bijnen, A. M. Rey, J. Ye, A. M. Kaufman, and P. Zoller, "Variational spin-squeezing algorithms on programmable quantum sensors", Phys. Rev. Lett., 123, 260505 (2019), DOI 10.1103/PhysRevLett.123.260505
Arrays of atoms trapped in optical tweezers combine features of programmable analog quantum simulators with atomic quantum sensors. Here we propose variational quantum algorithms, tailored for tweezer arrays as programmable quantum sensors, capable of generating entangled states on demand for precision metrology. The scheme is designed to generate metrological enhancement by optimizing it in a feedback loop on the quantum device itself, thus preparing the best entangled states given the available quantum resources. We apply our ideas to the generation of spin-squeezed states on Sr atom tweezer arrays, where finite-range interactions are generated through Rydberg dressing. The complexity of experimental variational optimization of our quantum circuits is expected to scale favorably with system size. We numerically show our approach to be robust to noise, and surpassing known protocols.
22. M. A. Perlin, D. Barberena, M. Mamaev, B. Sundar, R. J. Lewis-Swan, and A. M. Rey, "Engineering infinite-range SU(n) interactions with spin-orbit-coupled fermions in an optical lattice", arxiv.org/abs/2109.11019 (2021)
We study multilevel fermions in an optical lattice described by the Hubbard model with on site SU(n)-symmetric interactions. We show that in an appropriate parameter regime this system can be mapped onto a spin model with all-to-all SU(n)-symmetric couplings. Raman pulses that address internal spin states modify the atomic dispersion relation and induce spin-orbit coupling, which can act as a synthetic inhomogeneous magnetic field that competes with the SU(n) exchange interactions. We investigate the mean-field dynamical phase diagram of the resulting model as a function of n and different initial configurations that are accessible with Raman pulses. Consistent with previous studies for n=2, we find that for some initial states the spin model exhibits two distinct dynamical phases that obey simple scaling relations with n. Moreover, for n>2 we find that dynamical behavior can be highly sensitive to initial intra-spin coherences. Our predictions are readily testable in current experiments with ultracold alkaline-earth(-like) atoms.
23. T. Bilitewski, A. Pineiro Orioli, C. Sanner, L. Sonderhouse, R. B. Hutson, L. Yan, W. R. Milner, J. Ye, and A. M. Rey, "Disentangling Pauli blocking of atomic decay from cooperative radiation and atomic motion in a 2D Fermi gas", arxiv.org/abs/2108.02819 (2021)
The observation of Pauli blocking of atomic spontaneous decay via direct measurements of the atomic population requires the use of long-lived atomic gases where quantum statistics, atom recoil and cooperative radiative processes are all relevant. We develop a theoretical framework capable of simultaneously accounting for all these effects in a regime where prior theoretical approaches based on semi-classical non-interacting or interacting frozen atom approximations fail. We apply it to atoms in a single 2D pancake or arrays of pancakes featuring an effective &\Lambda$level structure (one excited and two degenerate ground states). We identify a parameter window in which a factor of two extension in the atomic lifetime clearly attributable to Pauli blocking should be experimentally observable in deeply degenerate gases with ∼103 atoms. Our predictions are supported by observation of a number-dependent excited state decay rate on the$^{1}S_{0}$-$^{3}P_{1}$transition in$^{87}Sr$atoms. 24. A. Pineiro Orioli, J. K. Thompson, A. M. Rey, "Emergent dark states from superradiant dynamics in multilevel atoms in a cavity", arxiv.org/abs/2106.00019 (2021) We investigate the collective decay dynamics of atoms with a generic multilevel structure (angular momenta F$\leftrightarrow$F$^{'}$coupled to two light modes of different polarization inside a cavity. In contrast to two-level atoms, we find that multilevel atoms can harbour eigenstates that are perfectly dark to cavity decay even within the subspace of permutationally symmetric states (collective Dicke manifold). The dark states arise from destructive interference between different internal transitions and are shown to be entangled. Remarkably, the superradiant decay of multilevel atoms can end up stuck in one of these dark states, where a macroscopic fraction of the atoms remains excited. This opens the door to the preparation of entangled dark states of matter through collective dissipation useful for quantum sensing and quantum simulation. Our predictions should be readily observable in current optical cavity experiments with alkaline-earth atoms or Raman-dressed transitions. 25. J. Huber, A. M. Rey, P. Rabi, "Realistic simulations of spin squeezing and cooperative coupling effects in large ensembles of interacting two-level systems", arxiv.org/abs/2105.00004 (2021) We describe an efficient numerical method for simulating the dynamics of interacting spin ensembles in the presence of dephasing and decay. The method builds on the discrete truncated Wigner approximation for isolated systems, which combines the mean-field dynamics of a spin ensemble with a Monte Carlo sampling of discrete initial spin values to account for quantum correlations. Here we show how this approach can be generalized for dissipative spin systems by replacing the deterministic mean-field evolution by a stochastic process, which describes the decay of coherences and populations while preserving the length of each spin. We demonstrate the application of this technique for simulating nonclassical spin-squeezing effects or the dynamics and steady states of cavity QED models with hundred thousand interacting two-level systems and without relying on any symmetries. This opens up the possibility to perform accurate real-scale simulations of a diverse range of experiments in quantum optics or with solid-state spin ensembles under realistic laboratory conditions. 26. A. Chu, P. He, J. K. Thompson, A. M. Rey, "Quantum enhanced cavity QED interferometer with partially delocalized atoms in lattices", arxiv.org/abs/2104.04204 (2021). We propose a quantum enhanced interferometric protocol for gravimetry and force sensing using cold atoms in an optical lattice supported by a standing-wave cavity. By loading the atoms in partially delocalized Wannier-Stark states, it is possible to cancel the undesirable inhomogeneities arising from the mismatch between the lattice and cavity fields and to generate spin squeezed states via a uniform one-axis twisting model. The quantum enhanced sensitivity of the states is combined with the subsequent application of a compound pulse sequence that allows to separate atoms by several lattice sites. This, together with the capability to load small atomic clouds in the lattice at micrometric distances from a surface, make our setup ideal for sensing short-range forces. We show that for arrays of$10^{4}$atoms, our protocol can reduce the required averaging time by a factor of 10 compared to unentangled lattice-based interferometers after accounting for primary sources of decoherence. 27. C. Sanner, L. Sonderhouse, R. B. Hutson, L. Yan, W R. Milner, and J. Ye, "Pauli blocking of atom-light scattering", Science Vol 374, Issue 6570, pp. 979-983, DOI: 10.1126/science.abh348 Transition rates between coupled states in a quantum system depend on the density of available final states. The radiative decay of an excited atomic state has been suppressed by reducing the density of electromagnetic vacuum modes near the atomic transition. Likewise, reducing the density of available momentum modes of the atomic motion when it is embedded inside a Fermi sea will suppress spontaneous emission and photon scattering rates. Here we report the experimental demonstration of suppressed light scattering in a quantum degenerate Fermi gas. We systematically measured the dependence of the suppression factor on the temperature and Fermi energy of a strontium quantum gas and achieved suppression of scattering rates by up to a factor of 2 compared with a thermal gas. 28. S. Omanakuttan, A. Mitra, M. J. Martin, and I. H. Deutsch, "Quantum optimal control of ten-level nuclear spin qudits in 87Sr", Phys. Rev. A 104, L060401, DOI: 10.1103/PhysRevA.104.L060401 We study the ability to implement unitary maps on states of the I = 9/2 nuclear spin in$^{87}$Sr, a d=10 dimensional (qudecimal) Hilbert space, using quantum optimal control. Through a combination of nuclear spin resonance and a tensor ac Stark shift, by solely modulating the phase of a radio-frequency magnetic field, the system is quantum controllable. Alkaline-earth-metal atoms, such as$^{87}$Sr, have a very favorable figure of merit for such control due to narrow intercombination lines and the large hyperfine splitting in the excited states. We numerically study the quantum speed limit, optimal parameters, and the fidelity of arbitrary state preparation and full SU(10) maps, including the presence of decoherence due to optical pumping induced by the light-shifting laser. We also study the use of robust control to mitigate some dephasing due to inhomogeneities in the light shift. We find that with an rf Rabi frequency of$\Omega_{rf}$and 0.5$\%$inhomogeneity in the the light shift we can prepare an arbitrary Haar-random state in a time$T = \frac{4.5\pi}{\Omega_{rf}}\$ with average fidelity $$= 0.9992, and an arbitrary Haar-random SU(10) map in a time T = \frac{24\pi}{\Omega_{rf}} with average fidelity$$ = 0.9923.

## Strongly Related Publications by Q-SEnSE Investigators

1. R. Srinivas, S. C. Burd, H. M. Knaack, R. T. Sutherland, A. Kwiatkowski, S. Glancy, E. Knill, D. J. Wineland, D. Leibfried, A. C. Wilson, D. T. C. Allcock, D. H. Slichter, "High-fidelity laser-free universal control of two trapped ion qubits", Nature 597, 209 (2021), DOI https://doi.org/10.1038/s41586-021-03809-4
2. A. W. Young, W. J. Eckner, W. R. Milner, D. Kedar, M. A. Norcia , E. Oelker , N. Schine , J. Ye & A. M. Kaufman, "Half-minute-scale atomic coherence and high relative stability in a tweezer clock", Nature, Vol 588, 17 December 2020
3. E. Pedrozo-Peñafiel, S. Colombo, C. Shu, A. F. Adiyatullin, Z. Li, E. Mendez, B.s Braverman, A. Kawasaki, D. Akamatsu, Y. Xiao and V. Vuletić, "Entanglement on an optical atomic-clock transition", Nature 588, 414–418, 16 December 2020, https://doi.org/10.1038/s41586-020-3006-1
4. J. Ye, N. Mavalvala, R. G. Beausoleil, P. M. Dehmer, L. L. Dimauro, M. Gaarde, S. Girvin, C. H. Greene, T. J. Ha, M. Kasevich, M. Lipson, M. D. Lukin, A. M. Lyyra, P. J. Reynolds, M. Safronova, and P. Zoller, "Manipulating Quantum Systems: An Assessment of Atomic, Molecular, and Optical Physics in the United States", http://nasedu/AMO2020 (2019) (2019). 10.17226/25613
5. S. C. Burd, R. Srinivas, J. J. Bollinger, A. C. Wilson, D. J. Wineland, D. Leibfried, D. H. Slichter, and D. T. C. Allcock, "Quantum amplification of mechanical oscillator motion", Science 364, 1163-1165 (2019). 10.1126/science.aaw2884
6. K. C. McCormick, J. Keller, S. C. Burd, D. J. Wineland, A. C. Wilson, and D. Leibfried, "Quantum-enhanced sensing of a single-ion mechanical oscillator", Nature 572, 86-90 (2019). 10.1038/s41586-019-1421-y
7. K. van Bibber, K. Lehnert, and A. Chou, "Putting the squeeze on axions", Phys Today 72, 48 (2019). 10.1063/PT.3.4227
8. J. Rudolph, T. Wilkason, M. Nantel, H. Swan, C. M. Holland, Y. Jiang, B. E. Garber, S. P. Carman, and J. M. Hogan, "Large Momentum Transfer Clock Atom Interferometry on the 689 nm Intercombination Line of Strontium", arXiv:191005459 (2019).
9. M. Mamaev, R. Blatt, J. Ye, and A. M. Rey, "Cluster State Generation with Spin-Orbit Coupled Fermionic Atoms in Optical Lattices", Phys Rev Lett 122, 160402 (2019). 10.1103/PhysRevLett.122.160402
10. J. M. Robinson, E. Oelker, W. R. Milner, W. Zhang, T. Legero, D. G. Matei, F. Riehle, U. Sterr, and J. Ye, "Crystalline optical cavity at 4 K with thermal-noise-limited instability and ultralow drift", Optica 6, 240-243 (2019). 10.1364/optica.6.000240
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