Program
Full Program | Thursday | Friday | Saturday | All Sessions | Posters | Talks
LSU SQuInT Event Map
SESSION 9b: Theoretical tools and analyses (JC Miller Hall, Rm 119)Chair: (Travis Scholten (Sandia, CQuIC New Mexico)) | |
| 3:45pm - 4:15pm | Christopher Granade, Sydney QInfer: Statistical inference software for quantum applications | Abstract. Characterizing quantum systems through experimental data is critical to applications as diverse as metrology and quantum computing. Analyzing this experimental data in a robust and reproducible manner is made challenging, however, by the lack of readily-available software for performing principled statistical analysis. In this talk, we introduce an open-source library, QInfer, to address this need and to improve the robustness and reproducibility of characterization experiments. We will show examples of how our library makes it easy to analyze data from tomography, randomized benchmarking, and Hamiltonian learning experiments either in post-processing, or online as data is acquired. We will discuss how QInfer also provides functionality for predicting the performance of proposed experimental protocols from simulated runs. By delivering easy-to-use characterization tools based on principled statistical analysis, QInfer helps address many outstanding challenges facing quantum technology. All source code and examples for this talk may be found online at qinfer.org. |
| 4:15pm - 4:45pm | Andrzej Veitia, Oregon Detecting non-Markovian effects in quantum computing architectures | Abstract. We present a family of tests for detection of non-Markovian effects in quantum gate sequences. A central feature of our method is its insensitivity to state preparation and measurement errors (SPAM). Although our method is not scalable, we will discuss its application to few-qubit systems as a means of detecting spatial correlations in a quantum computing architectures |
| 4:45pm - 5:15pm | Jan Kolodynski, ICFO Random bosonic states for robust quantum metrology | Abstract. We study how useful random states are for quantum metrology, i.e., whether they surpass the classical limits imposed on precision in the canonical phase sensing scenario. First, we prove that random pure states drawn from the Hilbert space of distinguishable particles typically do not lead to superclassical scaling of precision even when allowing for local unitary optimization. Conversely, we show that random pure states from the symmetric subspace typically achieve the optimal Heisenberg scaling without the need for local unitary optimization. Surprisingly, the Heisenberg scaling is observed for random isospectral states of arbitrarily low purity and preserved under loss of a fixed number of particles. Moreover, we prove that for pure states, a standard photon-counting interferometric measurement suffices to typically achieve resolutions following the Heisenberg scaling for all values of the phase at the same time. Finally, we demonstrate that metrologically useful states can be prepared with short random optical circuits generated from three types of beam splitters and a single nonlinear (Kerr-like) transformation. |
| 5:15pm - 5:45pm | Fabricio Toscano, Instituto de Fisica, Universidade Federal do Rio de Janeiro (UFRJ), Brasil Attainability of the quantum information bound in pure state models | Abstract. The attainability of the quantum Cramer-Rao bound [QCR], the ultimate limit in the precision of the estimation of a physical parameter, requires the saturation of the quantum information bound [QIB]. This occurs when the Fisher information associated to a given measurement on the quantum state of a system which encodes the information about the parameter coincides with the quantum Fisher information associated to that quantum state. Braunstein and Caves [PRL 72, 3439 (1994)] have shown that the QIB can always be achieved via a projective measurement in the eigenvectors basis of an observable called symmetric logarithmic derivative. However, such projective measurement depends, in general, on the value of the parameter to be estimated. Requiring, therefore, the previous knowledge of the quantity one is trying to estimate. For this reason, it is important to investigate under which situation it is possible to saturate the QCR without previous information about the parameter to be estimated. Here, we show the complete solution to the problem of which are all the initial pure states and the projective measurements that allow the global saturation of the QIB, without the knowledge of the true value of the parameter, when the information about the parameter is encoded in the system by a unitary process. |
| 5:45pm - 6:15pm | Gilad Gour, Calgary Single-shot quantum resource theories | Abstract. One of the main goals of any resource theory such as entanglement, quantum thermodynamics, quantum coherence, and asymmetry, is to find necessary and sufficient conditions (NSC) that determine whether one resource can be converted to another by the set of free operations. In this talk I will present such NSC for a large class of quantum resource theories which we call affine resource theories (ARTs). ARTs include the resource theories of athermality, asymmetry, and coherence, but not entanglement. Remarkably, the NSC can be expressed as a family of inequalities between resource monotones (quantifiers) that are given in terms of the conditional min entropy. The set of free operations is taken to be (1) the maximal set (i.e. consists of all resource non-generating (RNG) quantum channels) or (2) the self-dual set of free operations (i.e. consists of all RNG maps for which the dual map is also RNG). As an example, I will discuss the applications of the results to quantum thermodynamics with Gibbs preserving operations, and several other ARTs. Finally, I will discuss the applications of these results to resource theories that are not affine. |
SQuInT Chief Organizer
Akimasa Miyake, Assistant Professor
amiyake@unm.edu
SQuInT Co-Organizer
Mark M. Wilde, Assistant Professor LSU
mwilde@phys.lsu.edu
SQuInT Administrator
Gloria Cordova
gjcordo1@unm.edu
505 277-1850
SQuInT Event Coordinator
Karen Jones, LSU
kjones@cct.lsu.edu
SQuInT Founder
Ivan Deutsch, Regents' Professor
ideutsch@unm.edu
