Exponential Qubit Reduction in Optimization for Financial Transaction Settlement

We extend the qubit-efficient encoding presented in [Tan et al., Quantum 5, 454 (2021)] and apply it to instances of the financial transaction settlement problem constructed from data provided by a regulated financial exchange. Our methods are directly applicable to any QUBO problem with linear inequality constraints. Our extension of previously proposed methods consists of a simplification in varying the number of qubits used to encode correlations as well as a new class of variational circuits which incorporate symmetries, thereby reducing sampling overhead, improving numerical stability and recovering the expression of the cost objective as a Hermitian observable. We also propose optimality-preserving methods to reduce variance in real-world data and substitute continuous slack variables. We benchmark our methods against standard QAOA for problems consisting of 16 transactions and obtain competitive results. Our newly proposed variational ansatz performs best overall. We demonstrate tackling problems with 128 transactions on real quantum hardware, exceeding previous results bounded by NISQ hardware by almost two orders of magnitude.Comment: 16 pages, 8 figure

Minimax mean estimator for the trine

We explore the question of state estimation for a qubit restricted to the $x$-$z$ plane of the Bloch sphere, with the trine measurement. In our earlier work [H. K. Ng and B.-G. Englert, eprint arXiv:1202.5136[quant-ph] (2012)], similarities between quantum tomography and the tomography of a classical die motivated us to apply a simple modification of the classical estimator for use in the quantum problem. This worked very well. In this article, we adapt a different aspect of the classical estimator to the quantum problem. In particular, we investigate the mean estimator, where the mean is taken with a weight function identical to that in the classical estimator but now with quantum constraints imposed. Among such mean estimators, we choose an optimal one with the smallest worst-case error-the minimax mean estimator-and compare its performance with that of other estimators. Despite the natural generalization of the classical approach, this minimax mean estimator does not work as well as one might expect from the analogous performance in the classical problem. While it outperforms the often-used maximum-likelihood estimator in having a smaller worst-case error, the advantage is not significant enough to justify the more complicated procedure required to construct it. The much simpler adapted estimator introduced in our earlier work is still more effective. Our previous work emphasized the similarities between classical and quantum state estimation; in contrast, this paper highlights how intuition gained from classical problems can sometimes fail in the quantum arena.Comment: 18 pages, 3 figure

Fatigue Testing a Mechanized Percussion Well Drilling System for Water Access in Western Africa

The Mechanized Percussion Well Drilling (MPWD) Collaboratory project seeks to design a simple mechanized well drilling system for drilling shallow water wells in Western Africa. Our client, Open Door Development (ODD), seeks to make water accessible to all in the region, but has had difficulty drilling through hard soil layers. To combat this problem, the MPWD team has worked closely with Mr. Joseph Longenecker to develop a mechanized percussion well drilling rig that is capable of drilling through these harder layers. Currently, the MPWD team is seeking to provide recommendations to improve the lifetime of our client’s new, fully mechanized rig design. This year, our team’s work has been focused specifically on analyzing the lifetime of the rig’s driveline chains and also on its frame. For the driveline chains, the team will be conducting fatigue testing on a model of the driveline system to determine which type of chain should be used on the rig. To determine the lifetime of the frame, the team will be performing a series of static, buckling, and fatigue finite element analyses on the rig’s frame. The most recent accomplishments of the MPWD team have nearly proved that their design for the loading application will be feasible for use on the actual testing rig and that multiple studies of finite element analysis can be performed to simulate the different rig frame loading scenarios.https://mosaic.messiah.edu/engr2021/1019/thumbnail.jp

Commitment readiness and relationship formation

The concept of being ready for a relationship is pervasive in popular culture, but theoretical and empirical research on readiness is lacking. We offer a conceptualization of commitment readiness and provide some of the first empirical work examining readiness among single individuals—specifically how this construct shapes various aspects of relationship formation. Using data from five independent samples of individuals not involved in romantic relationships, we first establish that commitment readiness is associated with more interest in developing a close romantic relationship (Studies 1a, 1b, 2) and with active pursuit of relationship initiation (Study 2). We then test whether readiness among single individuals longitudinally predicts both the likelihood of later entering a relationship and, ultimately, how committed individuals are to a future relationship (Studies 3a, 3b, 3c). Implications of commitment readiness specifically, and perceived personal timing more generally, for the social psychology of relationships are discussed. </jats:p

The regulation of miRNAs by reconstituted high-density lipoproteins in diabetes-impaired angiogenesis

Diabetic vascular complications are associated with impaired ischaemia-driven angiogenesis. We recently found that reconstituted high-density lipoproteins (rHDL) rescue diabetes-impaired angiogenesis. microRNAs (miRNAs) regulate angiogenesis and are transported within HDL to sites of injury/repair. The role of miRNAs in the rescue of diabetes-impaired angiogenesis by rHDL is unknown. Using a miRNA array, we found that rHDL inhibits hsa-miR-181c-5p expression in vitro and using a hsa-miR-181c-5p mimic and antimiR identify a novel anti-angiogenic role for miR-181c-5p. miRNA expression was tracked over time post-hindlimb ischaemic induction in diabetic mice. Early post-ischaemia when angiogenesis is important, rHDL suppressed hindlimb mmu-miR-181c-5p. mmu-miR-181c-5p was not detected in the plasma or within HDL, suggesting rHDL specifically targets mmu-miR-181c-5p at the ischaemic site. Three known angiogenic miRNAs (mmu-miR-223-3p, mmu-miR-27b-3p, mmu-miR-92a-3p) were elevated in the HDL fraction of diabetic rHDL-infused mice early post-ischaemia. This was accompanied by a decrease in plasma levels. Only mmu-miR-223-3p levels were elevated in the hindlimb 3 days post-ischaemia, indicating that rHDL regulates mmu-miR-223-3p in a time-dependent and site-specific manner. The early regulation of miRNAs, particularly miR-181c-5p, may underpin the rescue of diabetes-impaired angiogenesis by rHDL and has implications for the treatment of diabetes-related vascular complications