22 research outputs found
Fast macroscopic-superposition-state generation by coherent driving
We propose a scheme to generate macroscopic superposition states in spin
ensembles, where a coherent driving field is applied to accelerate the
generation of macroscopic superposition states. The numerical calculation
demonstrates that this approach allows us to generate a superposition of two
classically distinct states of the spin ensemble with a high fidelity above
0.96 for 300 spins. For the larger spin ensemble, though the fidelity slightly
decline, it maintains above 0.85 for an ensemble of 500 spins. The time to
generate a macroscopic superposition state is also numerically calculated,
which shows that the significantly shortened generation time allows us to
achieve such macroscopic superposition states within a typical coherence time
of the system.Comment: 17 pages, 15 figure
Precision Measurements Using Squeezed Spin States via Two-axis Counter-twisting Interactions
We show that the two-axis counter twisting interaction squeezes a coherent
spin state into three states of interest in quantum information, namely, the
twin-Fock state, the equally-weighted superposition state, and the state that
achieves the Heisenberg limit of optimal sensitivity defined by the Cramer-Rao
inequality in addition to the well-known Heisenberg-limited state of spin
fluctuations.Comment: 5 pages, 3 figure
Scaling the stimulated emission of polarization-entangled photons using passive optical components
Bright sources of polarization-entangled photon pairs are essential
components for quantum information technologies. In general, it is necessary to
introduce a resonator that combines active optical components such as an
electric optical modulator to enhance the stimulated emission of
polarization-entangled photons. It is technically difficult to perform the time
series operation to output the stimulated entangled photons in the resonator by
synchronizing laser pulses. In this paper, we propose a scheme to scale up the
stimulated emission of polarization-entangled photon pairs using a resonator
with only passive optical components. We show the theoretical aspects of the
scheme and also perform a proof-of-principle experimental demonstration of the
scheme in a double-pass configuration.Comment: 8 pages, 6 figures, Physical Review A to be publishe
High expression of tumour-associated trypsin inhibitor correlates with liver metastasis and poor prognosis in colorectal cancer
Increased expression of tumour-associated trypsin inhibitor (TATI) in tumour tissue and/or serum has been associated with poor survival in various cancer forms. Moreover, a proinvasive function of TATI has been shown in colon cancer cell lines. In this study, we have examined the prognostic significance of tumour-specific TATI expression in colorectal cancer, assessed by immunohistochemistry (IHC) on tissue microarrays (TMAs) with tumour specimens from two independent patient cohorts. Kaplan–Meier analysis and Cox proportional hazards modelling were used to estimate time to recurrence, disease-free survival and overall survival. In both cohorts, a high (>50% of tumour cells) TATI expression was an independent predictor of a significantly shorter overall survival. In cohort II, in multivariate analysis including age, gender, disease stage, differentiation grade, vascular invasion and carcinoembryonal antigen (CEA), high TATI expression was associated with a significantly decreased overall survival (HR=1.82; 95% CI=1.19–2.79) and disease-free survival (HR=1.56; 95% CI=1.05–2.32) in curatively treated patients. Moreover, there was an increased risk for liver metastasis in both cohorts that remained significant in multivariate analysis in cohort II (HR=2.85; 95% CI=1.43–5.66). In conclusion, high TATI expression is associated with liver metastasis and is an independent predictor of poor prognosis in patients with colorectal cancer