Convergent Cross-Mapping (CCM) has shown high potential to perform causal inference in the absence of models. We assess the strengths and weaknesses of the method by varying coupling strength and noise levels in coupled logistic maps. We... more
Convergent Cross-Mapping (CCM) has shown high potential to perform causal inference in the absence of models. We assess the strengths and weaknesses of the method by varying coupling strength and noise levels in coupled logistic maps. We find that CCM fails to infer accurate coupling strength and even causality direction in synchronized time-series and in the presence of intermediate coupling. We find that the presence of noise deterministically reduces the level of cross-mapping fidelity, while the convergence rate exhibits higher levels of robustness. Finally, we propose that controlled noise injections in intermediate-to-strongly coupled systems could enable more accurate causal inferences. Given the inherent noisy nature of real-world systems, our findings enable a more accurate evaluation of CCM applicability and advance suggestions on how to overcome its weaknesses.
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We demonstrate the efficiency of a recent exact-gradient optimal control methodology by applying it to a challenging many-body problem described by matrix product states. In contrast to previous, gradient-free, optimization on the same... more
We demonstrate the efficiency of a recent exact-gradient optimal control methodology by applying it to a challenging many-body problem described by matrix product states. In contrast to previous, gradient-free, optimization on the same problem yielding maximally 0.7 fidelity, we observe fidelities in the range 0.99-0.9999 and beyond with associated minimal duration estimates displaying a characteristic, exponential fidelity-duration trade-off across several orders of magnitude. Additionally, whereas previously attained control shapes were smooth and monotonic, we identify a hierarchy of sequentially optimal solutions with an increased information-theoretic control complexity. These facilitate nonadiabatic quantum interference pathways using sequential tunneling and phase-imprinting dynamics necessary for high fidelity. The documented performance of the new analytically exact gradients both in theory and numerical practice across the extremes of Hilbert space size asserts wide applic...
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The rise of digital technologies and Machine Learning (ML)-tools for creative expression brings about novel opportunities for studying creativity and cognition at scale. In this paper, we present a pilot study of crea.blender SDG - an... more
The rise of digital technologies and Machine Learning (ML)-tools for creative expression brings about novel opportunities for studying creativity and cognition at scale. In this paper, we present a pilot study of crea.blender SDG - an online GAN based image generation game. We designed crea.blender SDG with two goals in mind: The first, to let people create images relating to the United Nations Sustainable Development Goals (SDGs) and through them, engage in large-scale conversations on complex socioscientific problems. The second, as a fun and inspiring gateway for public participation in research, generating data for the creativity and cognition research and design community. Specifically in this pilot, we study and affirm that the design of crea.blender SDG is flexible enough to allow users to create images that express both anxiety and hope for the future; affirm that user generated images express these ideas in ways that are meaningful to people other than the original creator;...
Research Interests: Computer Science and Acm
Sourav Manna, 2 Callum W. Duncan, 3 Carrie A. Weidner, Jacob F. Sherson, and Anne E. B. Nielsen 4 Max-Planck-Institut für Physik komplexer Systeme, D-01187 Dresden, Germany Department of Condensed Matter Physics, Weizmann Institute of... more
Sourav Manna, 2 Callum W. Duncan, 3 Carrie A. Weidner, Jacob F. Sherson, and Anne E. B. Nielsen 4 Max-Planck-Institut für Physik komplexer Systeme, D-01187 Dresden, Germany Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 7610001, Israel Department of Physics, SUPA and University of Strathclyde, Glasgow G4 0NG, United Kingdom Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
We show that it is possible to generate continuous-wave fields and pulses of polarization squeezed light by sending classical, linearly polarized laser light twice through an atomic sample which causes an optical Faraday rotation of the... more
We show that it is possible to generate continuous-wave fields and pulses of polarization squeezed light by sending classical, linearly polarized laser light twice through an atomic sample which causes an optical Faraday rotation of the field polarization. We characterize the performance of the process, and we show that an appreciable degree of squeezing can be obtained under realistic physical assumptions.
Knowledge of quantum mechanical systems is becoming more important for many science and engineering students who are looking to join the emerging quantum workforce. To better prepare a wide range of students for these careers, we must... more
Knowledge of quantum mechanical systems is becoming more important for many science and engineering students who are looking to join the emerging quantum workforce. To better prepare a wide range of students for these careers, we must seek to develop new tools to enhance our education in quantum topics. We present initial studies on the use of one of these such tools, Quantum Composer, a 1D quantum simulation and visualization tool developed for education and research purposes. In particular, we conducted five think-aloud interviews with students who worked through an exercise using Quantum Composer that focused on the statics and dynamics of quantum states in singleand double-harmonic well systems. Our results show that Quantum Composer helps students to obtain the correct answers to the questions posed, but additional support is needed to facilitate the development of student reasoning behind these answers. In addition, we find that students explore familiar and unfamiliar problem...
Development of outreach skills is critical for researchers when communicating their work to non-expert audiences. However, due to the lack of formal training, researchers are typically unaware of the benefits of outreach training and... more
Development of outreach skills is critical for researchers when communicating their work to non-expert audiences. However, due to the lack of formal training, researchers are typically unaware of the benefits of outreach training and often under-prioritize outreach. We present a training programme conducted with an international network of PhD students in quantum physics, which focused on developing outreach skills and an understanding of the associated professional benefits by creating an outreach portfolio consisting of a range of implementable outreach products. We describe our approach, assess the impact, and provide guidelines for designing similar programmes across scientific disciplines in the future.
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ABSTRACT Creativity assessments should be valid, reliable, and scalable to support various stakeholders (e.g., policy-makers, educators, corporations, and the general public) in their decision-making processes. Established initiatives... more
ABSTRACT Creativity assessments should be valid, reliable, and scalable to support various stakeholders (e.g., policy-makers, educators, corporations, and the general public) in their decision-making processes. Established initiatives toward scalable creativity assessments have relied on well-studied standardized tests. Although robust in many ways, most of these tests adopt unnatural and unmotivating environments for expression of creativity, mainly observe coarse-grained snippets of the creative process, and rely on subjective, resource-intensive, human-expert evaluations. This article presents a literature review of game-based creativity assessment and discusses how digital games can potentially address the limitations of traditional testing. Based on an original sample of 127 papers, this article contributes an in-depth review of 16 papers on 11 digital creativity assessment games. Despite the relatively small sample, a wide variety of design decisions are covered. Major findings and recommendations include identifying (1) a disconnect between the potential of scaling up assessment of creativity with the use of digital games, and the actual reach achieved in the examined studies (2) the need for complementary methods such as stealth assessment, algorithmic support and crowdsourcing when designing creativity assessment games, and (3) a need for interdisciplinary dialogs to produce, validate and implement creativity assessment games at scale.
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Computational modeling is widely used to study how humans and organizations search and solve problems in fields such as economics, management, cultural evolution, and computer science. We argue that current computational modeling research... more
Computational modeling is widely used to study how humans and organizations search and solve problems in fields such as economics, management, cultural evolution, and computer science. We argue that current computational modeling research on human problem-solving needs to address several fundamental issues in order to generate more meaningful and falsifiable contributions. Based on comparative simulations and a new type of visualization of how to assess the nature of the fitness landscape, we address two key assumptions that approaches such as the NK framework rely on: that the NK captures the continuum of the complexity of empirical fitness landscapes and that search behavior is a distinct component, independent from the topology of the fitness landscape. We show the limitations of the most common approach to conceptualize how complex, or rugged, a landscape is, as well as how the nature of the fitness landscape is fundamentally intertwined with search behavior. Finally, we outline...
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We present the results of an exploratory player experience study on the game Quantum Moves, a citizen science game where players move quantum particles to help create a quantum computer. Eight-hundred-and-seventeen players responded to a... more
We present the results of an exploratory player experience study on the game Quantum Moves, a citizen science game where players move quantum particles to help create a quantum computer. Eight-hundred-and-seventeen players responded to a 13-question exploratory survey constructed to understand how players relate to the game, what are their motivations, and how could the game be improved. We analyzed the data using descriptive statistics and thematic analysis. Specifically, the thematic analysis helped identifying two cross-cutting themes amongst the players: (a) learning and (b) the opportunity to contribute to science. Results indicate that the opportunity to help science, along with game design, game elements, involvement of players with the scientific community, and players’ strategies influence experience. Implications of the particular findings for the research on player experience on citizen science games and development of evaluation methods are discussed.
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As educators push for students to learn science by doing science, there is a need for computational scaffolding to assist students' evaluation of scientific evidence and argument building. In this paper, we present a pilot study of... more
As educators push for students to learn science by doing science, there is a need for computational scaffolding to assist students' evaluation of scientific evidence and argument building. In this paper, we present a pilot study of SciNote, a CSCL tool allowing educators to integrate third-party software into a flexible and collaborative workspace. We explore how SciNote enables teams to build data-driven arguments during inquiry-based learning activities.
We present an experimentally feasible protocol for the complete storage and retrieval of arbitrary light states in an atomic quantum memory using the Faraday interaction between light and matter. Our protocol relies on multiple passages... more
We present an experimentally feasible protocol for the complete storage and retrieval of arbitrary light states in an atomic quantum memory using the Faraday interaction between light and matter. Our protocol relies on multiple passages of a single light pulse through the atomic ensemble without the impractical requirement of kilometer-long delay lines between the passages. A time-dependent interaction strength enables the storage and retrieval of states with arbitrary pulse shapes. The fidelity approaches unity exponentially without squeezed or entangled initial states, as illustrated by calculations for a photonic qubit.
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We present a complete architecture for scalable quantum computation with ultracold atoms in optical lattices using optical tweezers focused to the size of a lattice spacing. We discuss three different two-qubit gates based on local... more
We present a complete architecture for scalable quantum computation with ultracold atoms in optical lattices using optical tweezers focused to the size of a lattice spacing. We discuss three different two-qubit gates based on local collisional interactions. The gates between arbitrary qubits require the transport of atoms to neighboring sites. We numerically optimize the nonadiabatic transport of the atoms through the lattice and the intensity ramps of the optical tweezer in order to maximize the gate fidelities. We find overall gate times of a few 100μs, while keeping the error probability due to vibrational excitations and spontaneous scattering below 10-3. The requirements on the positioning error and intensity noise of the optical tweezer and the magnetic field stability are analyzed and we show that atoms in optical lattices could meet the requirements for fault-tolerant scalable quantum computing.
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Steps towards implementing a collision based two-qubit gate in optical lattices have previously been realized by the parallel merging all pairs of atoms in a periodicity two superlattice. In contrast, we propose an architecture which... more
Steps towards implementing a collision based two-qubit gate in optical lattices have previously been realized by the parallel merging all pairs of atoms in a periodicity two superlattice. In contrast, we propose an architecture which allows for the merger of a selected qubit pair in a novel long-periodicity superlattice structure consisting of two optical lattices with close-lying periodicity. We numerically optimize the gate time and fidelity, including the effects on neighboring atoms, and in the presence of experimental sources of error. Furthermore, the superlattice architecture induces a differential hyperfine shift, allowing for single-qubit gates. The fastest possible single-qubit gate times, given a maximal tolerable rotation error on the remaining atoms at various values of the lattice wavelengths, are identified. We find that robust single- and two-qubit gates with gate times of a few 100~$\mu$s and with error probabilities $\sim{}10^{-3}$ are possible.
We present a Gaussian-state analysis of the entanglement generation between two macroscopic atomic ensembles due the continuous probing of collective spin variables by optical Faraday rotation. The evolution of the mean values and the... more
We present a Gaussian-state analysis of the entanglement generation between two macroscopic atomic ensembles due the continuous probing of collective spin variables by optical Faraday rotation. The evolution of the mean values and the variances of the atomic variables is determined, and the entanglement is characterized by the Gaussian entanglement of formation and the logarithmic negativity. The effects of induced opposite Larmor rotation of the samples and of light absorption and atomic decay are analyzed in detail.
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Single site resolution in short-wavelength optical lattices, which have a significant tunnel coupling, is a challenging task. We prepare a BEC of rubidium atoms in a 3D lattice of 532 nm spacing. Using the 5S1/2 to 6P3/2 transition at... more
Single site resolution in short-wavelength optical lattices, which have a significant tunnel coupling, is a challenging task. We prepare a BEC of rubidium atoms in a 3D lattice of 532 nm spacing. Using the 5S1/2 to 6P3/2 transition at 420nm, our imaging system (NA=0.7) will yield a resolution of 380nm and there-fore allow single site resolved detection and manipulation. So
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ABSTRACT We discuss protocols for mapping quantum states of light onto atomic spins, including the recently demonstrated quantum teleportation between light and matter. We show how these protocols can be improved using spin and light... more
ABSTRACT We discuss protocols for mapping quantum states of light onto atomic spins, including the recently demonstrated quantum teleportation between light and matter. We show how these protocols can be improved using spin and light squeezing.
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Investigations of ultracold quantum gases in optical lattices are mostly restricted to access global information of the system. By contrasts we are developing experimental techniques revealing the local distribution of the trapped gas.... more
Investigations of ultracold quantum gases in optical lattices are mostly restricted to access global information of the system. By contrasts we are developing experimental techniques revealing the local distribution of the trapped gas. Main part of the experiment will be an optical imagine system with a spatial resolution better than the lattice spacing of a near infrared optical lattice. In addition the setup will allow for manipulation of the atoms on a local scale. Collecting the fluorescence light of the trapped atoms, will enable us to observe the local dynamics of the many-body system. With an additional strongly focused laser beam single sites of the optical lattice can be addressed. Possible applications of single site addressability are e.g. single q- bit rotations via local rf-resonance or disturbance of the many- body system on a local scale. In principle the experimental setup will open new possibilities for the investigation and manipulation of strongly correlated atomi...
The reliable detection of single quantum particles has revolutionized the field of quantum optics and quantum information processing. For several years, researchers have aspired to extend such detection possibilities to larger-scale,... more
The reliable detection of single quantum particles has revolutionized the field of quantum optics and quantum information processing. For several years, researchers have aspired to extend such detection possibilities to larger-scale, strongly correlated quantum systems. We report on fluorescence imaging of bosonic Mott insulators in an optical lattice with single-atom and single-site resolution.ootnotetextJ. Sherson et al., Nature 467, 68 (2010) From our images, we fully reconstruct the atom distribution on the lattice and identify individual excitations with high fidelity. Furthermore we will present progress towards in-situ thermometry and the detection of coherent particle-hole excitations across the superfluid-to-Mott-insulator transition. We plan to use our detection technique to study one dimensional quantum systems. In the Tonks-Girardeau regime, their strongly interacting nature can be revealed by the density-density correlation function, which should show a distinct anti-bu...
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ABSTRACT Single site resolution in short-wavelength optical lattices, which have a significant tunnel coupling, is a challenging task. We prepare a BEC of rubidium atoms in a 3D lattice of 532 nm spacing. Using the 5S1/2 to 6P3/2... more
ABSTRACT Single site resolution in short-wavelength optical lattices, which have a significant tunnel coupling, is a challenging task. We prepare a BEC of rubidium atoms in a 3D lattice of 532 nm spacing. Using the 5S1/2 to 6P3/2 transition at 420nm, our imaging system (NA=0.7) will yield a resolution of 380nm and there-fore allow single site resolved detection and manipulation. So far we have taken in trap fluorescence images with a resolution of 700 nm using the 5S1/2 to 5P3/2 transition at 780nm and demonstrated the micro-manipulation of a few atoms with a tightly focused dipole trap. To extract one or a few slices and remove the atoms that are out of the depth of focus we use microwave transitions in a magnetic field gradient. The single site resolution will open up a new class of experiments in quantum simulation of strongly correlated systems - like the in-situ observation of the Mott insulator or the investigation of non-equilibrium phenomena - and in quantum information processing - like local spin manipulation or quantum gates with Rydberg atoms.