Maximum-likelihood coherent-state quantum process tomography

Coherent-state quantum process tomography (csQPT) is a method of completely characterizing a quantum-optical "black box" by probing it with coherent states and performing homodyne measurements on the output [M. Lobino et al, Science 322, 563 (2008)]. We present a technique for csQPT that is fully based on statistical inference, specifically, quantum expectation-maximization. The method relies on the Jamiolkowski isomorphism and iteratively reconstructs the process tensor in the Fock basis directly from the experimental data. This approach permits incorporation of a priori constraints into the reconstruction procedure, thereby guaranteeing that the resulting process tensor is physically consistent. Furthermore, our method is easier to implement and requires a narrower range of coherent states than its predecessors. We test its feasibility using simulations on several experimentally relevant processes.Comment: 17 pages, 4 figure

Differences in angiographic profile and immediate outcome of primary percutaneous coronary intervention in otherwise risk-free young male smokers

Introduction: Cigarette smoking is a well-established risk factor for the development and progression of coronary artery disease (CAD) and it is strongly related to cardiac morbidity and mortality. Therefore, this study aimed to compare the angiographic profile and immediate clinical outcomes in young male smokers and non-smokers without any other cardiac risk factors presented with ST-elevation myocardial infarction (STEMI).Methods: This study includes young (≤40 years) male patients presented without cardiac risk factors other than smoking. Angiographic profile and immediate outcome of primary percutaneous coronary intervention (PCI) were collected from the hospital database.Results: A total of 580 young male patients were included in this study, 51.2% (297) were smokers. Baseline characteristics and presentation were similar for smoker and non-smoker groups. Angiographic profile was not significantly different for smokers in terms of pre-procedure thrombolysis in myocardial infarction (TIMI) flow (p = 0.373), the number of vessels involved (p = 0.813), infarct-related artery (p = 0.834), and left ventricular dysfunction (p = 0.311). Similarly, in-hospital outcomes of primary PCI were not significantly different in smokers. Post-procedure no-reflow was in 3.4% vs. 2.8%; p = 0.708, acute stent thrombosis in 1.7% vs. 0.4%; p = 0.114 and in-hospital mortality in 1.0% vs. 1.4%; p = 0.657 of the smoker and non-smoker group, respectively.Conclusion: Our study concludes smoking has no significant impact on the angiographic profile and immediate clinical outcomes of primary PCI after STEMI in young males, without any other conventional cardiac risk factors. With these findings, further multicenter prospective studies are needed to identify other potential causes in such patients