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Full-Text Articles in Optics
Uncertainty Relation For Mutual Information, James Schneeloch, Curtis J. Broadbent, John C. Howell
Uncertainty Relation For Mutual Information, James Schneeloch, Curtis J. Broadbent, John C. Howell
Mathematics, Physics, and Computer Science Faculty Articles and Research
We postulate the existence of a universal uncertainty relation between the quantum and classical mutual informations between pairs of quantum systems. Specifically, we propose that the sum of the classical mutual information, determined by two mutually unbiased pairs of observables, never exceeds the quantum mutual information. We call this the complementary-quantum correlation (CQC) relation and prove its validity for pure states, for states with one maximally mixed subsystem, and for all states when one measurement is minimally disturbing. We provide results of a Monte Carlo simulation suggesting that the CQC relation is generally valid. Importantly, we also show that the …
Paraxial Ray Optics Cloaking, Joseph S. Choi, John C. Howell
Paraxial Ray Optics Cloaking, Joseph S. Choi, John C. Howell
Mathematics, Physics, and Computer Science Faculty Articles and Research
Despite much interest and progress in optical spatial cloaking, a three-dimensional (3D), transmitting, continuously multidirectional cloak in the visible regime has not yet been demonstrated. Here we experimentally demonstrate such a cloak using ray optics, albeit with some edge effects. Our device requires no new materials, uses isotropic off-the-shelf optics, scales easily to cloak arbitrarily large objects, and is as broadband as the choice of optical material, all of which have been challenges for current cloaking schemes. In addition, we provide a concise formalism that quantifies and produces perfect optical cloaks in the small-angle (‘paraxial’) limit.
Compressive Wavefront Sensing With Weak Values, Gregory A. Howland, Daniel J. Lum, John C. Howell
Compressive Wavefront Sensing With Weak Values, Gregory A. Howland, Daniel J. Lum, John C. Howell
Mathematics, Physics, and Computer Science Faculty Articles and Research
We demonstrate a wavefront sensor that unites weak measurement and the compressive-sensing, single-pixel camera. Using a high-resolution spatial light modulator (SLM) as a variable waveplate, we weakly couple an optical field’s transverse-position and polarization degrees of freedom. By placing random, binary patterns on the SLM, polarization serves as a meter for directly measuring random projections of the wavefront’s real and imaginary components. Compressive-sensing optimization techniques can then recover the wavefront. We acquire high quality, 256 × 256 pixel images of the wavefront from only 10,000 projections. Photon-counting detectors give sub-picowatt sensitivity.
Simultaneous Measurement Of Complementary Observables With Compressive Sensing, Gregory A. Howland, James Schneeloch, Daniel J. Lum, John C. Howell
Simultaneous Measurement Of Complementary Observables With Compressive Sensing, Gregory A. Howland, James Schneeloch, Daniel J. Lum, John C. Howell
Mathematics, Physics, and Computer Science Faculty Articles and Research
The more information a measurement provides about a quantum system’s position statistics, the less information a subsequent measurement can provide about the system’s momentum statistics. This information trade-off is embodied in the entropic formulation of the uncertainty principle. Traditionally, uncertainly relations correspond to resolution limits; increasing a detector’s position sensitivity decreases its momentum sensitivity and vice versa. However, this is not required in general; for example, position information can instead be extracted at the cost of noise in momentum. Using random, partial projections in position followed by strong measurements in momentum, we efficiently determine the transverse-position and transverse-momentum distributions of …
Avoiding Loopholes With Hybrid Bell-Leggett-Garg Inequalities, Justin Dressel, Alexander N. Korotkov
Avoiding Loopholes With Hybrid Bell-Leggett-Garg Inequalities, Justin Dressel, Alexander N. Korotkov
Mathematics, Physics, and Computer Science Faculty Articles and Research
By combining the postulates of macrorealism with Bell locality, we derive a qualitatively different hybrid inequality that avoids two loopholes that commonly appear in Leggett-Garg and Bell inequalities. First, locally invasive measurements can be used, which avoids the “clumsiness” Leggett-Garg inequality loophole. Second, a single experimental ensemble with fixed analyzer settings is sampled, which avoids the “disjoint sampling” Bell inequality loophole. The derived hybrid inequality has the same form as the Clauser-Horne-Shimony-Holt Bell inequality; however, its quantum violation intriguingly requires weak measurements. A realistic explanation of an observed violation requires either the failure of Bell locality or a preparation conspiracy …
Improving Einstein–Podolsky–Rosen Steering Inequalities With State Information, James Schneeloch, Curtis J. Broadbent, John C. Howell
Improving Einstein–Podolsky–Rosen Steering Inequalities With State Information, James Schneeloch, Curtis J. Broadbent, John C. Howell
Mathematics, Physics, and Computer Science Faculty Articles and Research
We discuss the relationship between entropic Einstein–Podolsky–Rosen (EPR)-steering inequalities and their underlying uncertainty relations along with the hypothesis that improved uncertainty relations lead to tighter EPR-steering inequalities. In particular, we discuss how using information about the state of a quantum system affects oneʼs ability to witness EPR-steering. As an example, we consider the recent improvement to the entropic uncertainty relation between pairs of discrete observables (Berta et al., 2010 [10]). By considering the assumptions that enter into the development of a steering inequality, we derive correct steering inequalities from these improved uncertainty relations and find that they are identical to …