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The measure of portfolio risk is an important input of the Markowitz framework. In this study, we explored various methods to obtain a robust covariance estimators that are less susceptible to financial data noise. We evaluated the…

Portfolio Management · Quantitative Finance 2024-06-04 Qiqin Zhou

A highly popular regularized (shrinkage) covariance matrix estimator is the shrinkage sample covariance matrix (SCM) which shares the same set of eigenvectors as the SCM but shrinks its eigenvalues toward the grand mean of the eigenvalues…

Methodology · Statistics 2020-10-29 Esa Ollila , Daniel P. Palomar , Frédéric Pascal

The scalable adaptive cubic regularization method ($\mathrm{ARC_{q}K}$: Dussault et al. in Math. Program. Ser. A 207(1-2): 191-225, 2024) has been recently proposed for unconstrained optimization. It has excellent convergence properties,…

Optimization and Control · Mathematics 2026-03-17 Yonggang Pei , Yubing Lin , Shuai Shao , Mauricio Silva Louzeiro , Detong Zhu

Sparse Inverse Covariance Estimation (SICE) is useful in many practical data analyses. Recovering the connectivity, non-connectivity graph of covariates is classified amongst the most important data mining and learning problems. In this…

Machine Learning · Computer Science 2019-04-05 Ashkan Esmaeili , Farokh Marvasti

Alleviating overestimation bias is a critical challenge for deep reinforcement learning to achieve successful performance on more complex tasks or offline datasets containing out-of-distribution data. In order to overcome overestimation…

Machine Learning · Computer Science 2024-01-09 Dohyeok Lee , Seungyub Han , Taehyun Cho , Jungwoo Lee

We consider the continuous-time Linear-Quadratic-Regulator (LQR) problem in terms of optimizing a real-valued matrix function over the set of feedback gains. The results developed are in parallel to those in Bu et al. [1] for discrete-time…

Systems and Control · Electrical Eng. & Systems 2020-06-17 Jingjing Bu , Afshin Mesbahi , Mehran Mesbahi

Squeezing currently represents the leading strategy for quantum enhanced precision measurements of a single parameter in a variety of continuous- and discrete-variable settings and technological applications. However, many important…

Quantum Physics · Physics 2020-07-31 Manuel Gessner , Augusto Smerzi , Luca Pezzè

In the classic scoring rule setting, a principal incentivizes an agent to truthfully report their probabilistic belief about some future outcome. This paper addresses the situation when this private belief, rather than a classical…

Computer Science and Game Theory · Computer Science 2022-03-16 Rafael Frongillo

Sieving using near-neighbor search techniques is a well-known method in lattice-based cryptanalysis, yielding the current best runtime for the shortest vector problem in both the classical [BDGL16] and quantum [BCSS23] setting. Recently,…

Quantum Physics · Physics 2024-12-25 Lynn Engelberts , Simona Etinski , Johanna Loyer

We study Bayesian inference in the spiked covariance model, where a small number of spiked eigenvalues dominate the spectrum. Our goal is to infer the spiked eigenvalues, their corresponding eigenvectors, and the number of spikes, providing…

Statistics Theory · Mathematics 2025-08-20 Kwangmin Lee , Sewon Park , Seongmin Kim , Jaeyong Lee

Variational Quantum Eigensolver (VQE) is a hybrid algorithm for finding the minimum eigenvalue/vector of a given Hamiltonian by optimizing a parametrized quantum circuit (PQC) using a classical computer. Sequential optimization methods,…

Quantum Physics · Physics 2024-05-17 Katsuhiro Endo , Yuki Sato , Rudy Raymond , Kaito Wada , Naoki Yamamoto , Hiroshi C. Watanabe

This paper presents a state and state-input constrained variant of the discrete-time iterative Linear Quadratic Regulator (iLQR) algorithm, with linear time-complexity in the number of time steps. The approach is based on a projection of…

Robotics · Computer Science 2018-05-25 Markus Giftthaler , Jonas Buchli

Hamiltonian simulation is a domain where quantum computers have the potential to outperform their classical counterparts. One of the main challenges of such quantum algorithms is increasing the system size, which is necessary to achieve…

Quantum Physics · Physics 2025-02-07 Erenay Karacan , Yanbin Chen , Christian B. Mendl

Uncertainty quantification (UQ) is vital for trustworthy deep learning, yet existing methods are either computationally intensive, such as Bayesian or ensemble methods, or provide only partial, task-specific estimates, such as…

Machine Learning · Computer Science 2025-09-18 Zhizhong Zhao , Ke Chen

This study explores the dual role of a squeezed reservoir in controlling the quantum phase synchronization of a driven two-level system. We first demonstrate, through a Liouvillian eigen-spectrum analysis, that the squeezed reservoir can…

Quantum Physics · Physics 2026-04-27 Xing Xiao , Tian-Xiang Lu , Wo-Jun Zhong , Yan-Ling Li

The aim of this thesis is to develop a theoretical framework to study parameter estimation of quantum channels. We study the task of estimating unknown parameters encoded in a channel in the sequential setting. A sequential strategy is the…

Quantum Physics · Physics 2022-01-06 Vishal Katariya

Qubit-efficient optimization studies how large combinatorial problems can be addressed with quantum circuits whose width is far smaller than the number of logical variables. In quadratic unconstrained binary optimization (QUBO), objective…

Quantum Physics · Physics 2026-01-13 Gordon Ma , Dimitris G. Angelakis

This paper presents the Safe Sequential Quadratically Constrained Quadratic Programming (SS-QCQP) algorithm, a first-order method for smooth inequality-constrained nonconvex optimization that guarantees feasibility at every iteration. The…

Optimization and Control · Mathematics 2025-11-26 Jiarui Wang , Mahyar Fazlyab

Existing deep learning methods have made significant progress in gait representation learning. Quantization can facilitate the application of gait models as a model-agnostic general compression technique. Typically, appearance-based models…

Computer Vision and Pattern Recognition · Computer Science 2026-03-24 S. Tian , H. Gao , G. Hong , S. Wang , J. Wang , X. Yu , S. Zhang

We study a signature-driven numerical scheme to solve multi-dimensional linear-quadratic (LQ) stochastic control problems. Using that linear signature functionals are dense in the natural class of admissible controls, we show that our…

Optimization and Control · Mathematics 2026-03-02 Alif Aqsha , Peter Bank , Leandro Sánchez-Betancourt
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