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1.
J Refract Surg ; 40(3): e126-e132, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38466764

ABSTRACT

PURPOSE: To use artificial intelligence (AI) technology to accurately predict vault and Implantable Collamer Lens (ICL) size. METHODS: The methodology focused on enhancing predictive capabilities through the fusion of machine-learning algorithms. Specifically, AdaBoost, Random Forest, Decision Tree, Support Vector Regression, LightGBM, and XGBoost were integrated into a majority-vote model. The performance of each model was evaluated using appropriate metrics such as accuracy, precision, F1-score, and area under the curve (AUC). RESULTS: The majority-vote model exhibited the highest performance among the classification models, with an accuracy of 81.9% area under the curve (AUC) of 0.807. Notably, LightGBM (accuracy = 0.788, AUC = 0.803) and XGBoost (ACC = 0.790, AUC = 0.801) demonstrated competitive results. For the ICL size prediction, the Random Forest model achieved an impressive accuracy of 85.3% (AUC = 0.973), whereas XG-Boost (accuracy = 0.834, AUC = 0.961) and LightGBM (accuracy = 0.816, AUC = 0.961) maintained their compatibility. CONCLUSIONS: This study highlights the potential of diverse machine learning algorithms to enhance postoperative vault and ICL size prediction, ultimately contributing to the safety of ICL implantation procedures. Furthermore, the introduction of the novel majority-vote model demonstrates its capability to combine the advantages of multiple models, yielding superior accuracy. Importantly, this study will empower ophthalmologists to use a precise tool for vault prediction, facilitating informed ICL size selection in clinical practice. [J Refract Surg. 2024;40(3):e126-e132.].


Subject(s)
Lenses, Intraocular , Phakic Intraocular Lenses , Humans , Artificial Intelligence , Machine Learning , Algorithms , Area Under Curve , Retrospective Studies
2.
Scand J Gastroenterol ; 59(5): 570-576, 2024 May.
Article in English | MEDLINE | ID: mdl-38252748

ABSTRACT

Objective: The purpose of this study was to explore the clinical benefits of establishing an enteral nutrition (EN) pathway via percutaneous transhepatic cholangiography drainage (PTCD) catheterization in patients with late-stage malignant obstructive jaundice (MOJ).Methods: We selected 30 patients diagnosed as having late-stage MOJ with malnutrition. A dual-lumen biliary-enteral nutrition tube was placed via PTCD along with a biliary stent implantation. Postoperative EN was provided, and we observed the time taken for tube placement, its success rate, complications, and therapeutic efficacy.Results: Tube placement was successful in all 30 patients with an average procedural time of 5.7 ± 1.4 min with no tube placement complications. Compared to preoperative measures, there was a significant improvement in postoperative jaundice reduction and nutritional indicators one month after the procedure (p < 0.05). Post-placement complications included tube perileakage in 5 cases, entero-biliary reflux in 4 cases, tube blockage in 6 cases, tube displacement in 4 cases, accidental tube removal in 3 cases, and tube replacement due to degradation in 8 cases, with tube retention time ranging from 42 to 314 days, averaging 124.7 ± 37.5 days. All patients achieved the parameters for effective home-based enteral nutrition with a noticeable improvement in their quality of life.Conclusion: In this study, we found that the technique of establishing an EN pathway via PTCD catheterization was minimally invasive, safe, and effective; the tube was easy to maintain; and patient compliance was high. It is, thus, suitable for long-term tube retention in patients with late-stage MOJ.


Subject(s)
Cholangiography , Drainage , Enteral Nutrition , Jaundice, Obstructive , Humans , Jaundice, Obstructive/etiology , Jaundice, Obstructive/therapy , Jaundice, Obstructive/surgery , Male , Female , Drainage/methods , Enteral Nutrition/methods , Middle Aged , Aged , Cholangiography/methods , Stents , Treatment Outcome , Catheterization/methods , Postoperative Complications/etiology , Malnutrition/etiology , Malnutrition/therapy , Aged, 80 and over
3.
Opt Express ; 30(15): 27794-27811, 2022 Jul 18.
Article in English | MEDLINE | ID: mdl-36236942

ABSTRACT

The resonance fluorescence properties in the steady-state regime are investigated for a driven cascaded exciton-biexciton quantum dot coupled to the two-dimensional black phosphorus metasurfaces. It is shown that for the material parameters under consideration, both the elliptic and hyperbolic dispersion patterns of the surface plasmon modes are achievable according to the variation of the carrier concentration. Further study on the Purcell factor indicates unequal enhancements in the spontaneous decay of the orthogonal in-plane dipoles. Motivated by this intriguing phenomenon, we then investigate the steady-state properties of the driven quantum dot, where the populations of the dressed levels are highly tunable by engineering the anisotropy of the surfaces. As a result, the manipulation of the carrier concentration will lead to strong modifications in the resonance fluorescence. Under certain conditions, one can observe the squeezing of two-mode noise spectra with different resonances and polarizations. Although at the expense of declines in the photon-sideband detunings, it is feasible to enhance the two-mode squeezing by gate doping. Our proposal can be easily extended to other hybrid systems containing anisotropic metasurfaces, which are important for the development of quantum information science.

4.
Opt Express ; 30(12): 21103-21124, 2022 Jun 06.
Article in English | MEDLINE | ID: mdl-36224839

ABSTRACT

We study the excitation conditions of the supported field modes, as well as the spontaneous decay property of a two-level quantum emitter coupled to photonic structures containing topological insulators (TIs) and left-handed materials. Within the proper field quantization scheme, the spontaneous decay rates of dipoles with different polarizations are expressed in forms of the Green's functions. We find that in the proposed structure, the variation in the topological magnetoelectric polarizability (TMP) has a deterministic effect on the excitation of different field modes. As the result, the spontaneous decay property of the quantum emitter can be engineered. For a dipole placed in different spatial regions, the spontaneous decay feature indicates a dominant contribution from the waveguide modes, the surface plasmon modes or the free vacuum modes. Moreover, a special kind of the surface plasmon modes displaying asymmetric density of states at the interfaces, becomes legal in the presence of nontrivial TIs. These phenomena manifest the feasibility in controlling dipole emissions via manipulations of the topological magnetoelectric (TME) effect. Our results have potential applications in quantum technologies relied on the accurate control over light-matter interactions.

5.
Opt Express ; 29(21): 33197-33209, 2021 Oct 11.
Article in English | MEDLINE | ID: mdl-34809136

ABSTRACT

We theoretically and experimentally investigate the laser-detected magnetic resonance spectra dressed by a radio-frequency magnetic field in Fg = 4 of D1 line of cesium atoms. The analytical expression of the transmission spectrum for magnetic resonance dressed by a radio-frequency magnetic field is derived and has substantial agreement with the transmission spectra observed in the experiment. The theoretical prediction of the ratio of the amplitudes of the two sidebands with the detuning is basically consistent with the experimental data, which confirms the validity of the analytical expression. The separation between the two sidebands under resonance shows a highly linear proportion to the amplitude of the dressing field, which may provide a useful scheme for the measurement of radio-frequency magnetic field and magnetic imaging.

6.
Opt Express ; 29(15): 23939-23952, 2021 Jul 19.
Article in English | MEDLINE | ID: mdl-34614648

ABSTRACT

The ultrastrongly coupling (USC) system has very important research significance in quantum simulation and quantum computing. In this paper, the ultranarrow spectrum of a circuit QED system with two qubits ultrastrongly coupled to a single-mode cavity is studied. In the regime of USC, the JC model breaks down and the counter-rotating terms in the quantum Rabi Hamiltonian leads to the level anti-crossing in the energy spectrum. Choosing a single-photon driving field at the point of avoided-level crossing, we can get an equivalent four-level dressed state model, in which the dissipation of the two intermediate states is only related to the qubits decay. Due to the electron shelving of these two metastable states, a narrow peak appears in the cavity emission spectrum. Furthermore, we find that the physical origin for the spectral narrowing is the vacuum-induced quantum interference between two transition pathways. And this interference effect couples the slowly decaying incoherent components of the density matrix into the equations of the sidebands. This result provides a possibility for the study of quantum interference effect in the USC system.

7.
Appl Opt ; 60(15): 4335-4339, 2021 May 20.
Article in English | MEDLINE | ID: mdl-34143122

ABSTRACT

The weak-value-amplification technique has shown great importance in the measurement of tiny physical effects. Here we introduce a polarization-dependent angular velocity measurement system consisting of two Glan prisms and a true zero-order half-wave plate, where a non-Fourier-limited Gaussian pulse acts as the meter. The angular velocities measurements results agree well with theoretical predictions, and its uncertainties are bounded by the Cramér-Rao bound. We also investigate uncertainties of angular velocities for different numbers of detected photons and the smallest reliable postselection probability, which can reach ${3.42*10^{- 6}}$.

8.
Opt Express ; 28(15): 22767-22790, 2020 Jul 20.
Article in English | MEDLINE | ID: mdl-32752533

ABSTRACT

Multifold wave-particle quantum correlations are studied in strongly correlated three-photon emissions from the Mollow triplet via frequency engineering. The nonclassicality and the non-Gaussianity of the filtered field are discussed by correlating intensity signal and correlated balanced homodyne signals. Due to the non-Gaussian fluctuations in the Mollow triplet, new forms of the criterion of nonclassicality for non-Gaussian radiation are proposed by introducing intensity-dual quadrature correlation functions, which contain the information about strongly correlated three-photon emissions of the Mollow triplet. In addition, the time-dependent dynamics of non-Gaussian fluctuations of the filtered field is studied, which displays conspicuous asymmetry. Physically, the asymmetrical evolution of non-Gaussian fluctuations can be attributed to the different transition dynamics of the laser-dressed quantum emitter revealed by the past quantum state and conditional quantum state. Compared with the conventional three-photon intensity correlations that unilaterally reflect the particle properties of radiation, the multifold wave-particle correlation functions we proposed may convey more information about wave-particle duality of radiation, such as the quantum coherence of photon triplet and "which-path" in cascaded photon emissions in atomic systems.

9.
Opt Express ; 28(1): 379-393, 2020 Jan 06.
Article in English | MEDLINE | ID: mdl-32118966

ABSTRACT

The intensity-amplitude correlation functions for a driven cavity QED system with two non-identical atoms are investigated in this paper. With the support of conditional homodyne detection, one can detect the time-dependent intensity-amplitude correlation functions experimentally. We find time-asymmetry in this correlation when the driving field is tuned to be resonant with the two-photon excitation state, which brings non-Gaussian fluctuations. The physical origin of these phenomena is the distinction of the third-order moment based on complete-collapse and partial-collapse, which corresponds to the measuring sequence of the intensity and amplitude. Finally, we also examined the nonclassical features of the system, which always exhibits photon bunching. The squeezing occurs in the region of weak driving and disappears with the increase of driving strength. Hence, a new classical inequality based on the technique of homodyne cross-correlation measurement is introduced to determine the nonclassicality of the non-Gaussian system in the region of unsqueezing.

10.
Opt Express ; 27(26): 37753-37770, 2019 Dec 23.
Article in English | MEDLINE | ID: mdl-31878551

ABSTRACT

Within the framework of macroscopic quantum electrodynamics, we investigate both the radiation force and the potential of Casimir-Polder type acting on an excited cold two-level atom in a cavity made of left-handed materials and topological insulators. As the time-reversal symmetry is broken on the surface of the topological insulators, the spontaneous emission of the atom placed near the focus point(s) exhibits anisotropic properties. While the potential wells are normally shallow for topological trivial dielectric, they may be amplified in the presence of topological magnetoelectric effect. We find that when there exists only one focus point in the cavity, it is possible to boost the forces or the potential wells by up to one order of magnitude. Meanwhile, the lifetime of the atom could be prolonged owing to the focus effect of the left-handed materials, where the emitted photons can trace back to the atom and reabsorbed by itself. Our results indicate the possibility in forming long-lived potential wells, which may have potential applications in trapping and guiding cold atoms far away from the surface.

11.
BJU Int ; 124(2): 258-267, 2019 08.
Article in English | MEDLINE | ID: mdl-30536520

ABSTRACT

OBJECTIVES: To identify biomarkers that predict the response to standard androgen deprivation therapy (ADT) of patients newly diagnosed with metastatic castration-sensitive prostate cancer (CSPC) in order to improve therapeutic decision-making, and to investigate whether the characterization of baseline circulating tumour cells (CTCs) would predict the effective period of standard ADT. MATERIALS AND METHODS: The study included 108 patients newly diagnosed with high-volume metastatic CSPC. Enumeration and characterization of patients' baseline CTCs (CTCs+ and CTCs-, indicating detectable and undetectable CTCs, respectively) were performed using the CanPatrol technique, which detects markers of the epithelial to mesenchymal transition (EMT) in CTCs, and classifies CTCs into epithelial, biophenotypic and mesenchymal phenotypes. RESULTS: After a median follow-up of 24 months, 90 patients (83.3%) progressed to castration-resistant prostate cancer (CRPC), 93 patients (86.1%) had detectable CTCs, and the median number of CTCs was 4. The rate of progression to CRPC was significantly higher for patients with mesenchymal CTCs+ than for patients with CTCs+/mesenchymal CTCs- and CTCs- (93.1% vs 71.4% and 73.3%; P = 0.013). The median time to CRPC for patients with mesenchymal CTCs+ was significantly shorter than for those with CTCs+/mesenchymal CTCs- and CTCs- (10.5 months vs 18.0 and 14.0 months; P = 0.003). Multivariate Cox regression analysis suggested that the CTC phenotype was the only independent prognostic factor influencing the progression of disease from CSPC to CRPC. CONCLUSIONS: Characterization of baseline CTCs according to the EMT phenotype predicted the effective period of standard ADT for patients newly diagnosed with metastatic CSPC. These findings are important for counselling patients and designing clinical trials.


Subject(s)
Androgen Antagonists/therapeutic use , Epithelial-Mesenchymal Transition , Neoplastic Cells, Circulating/pathology , Prostatic Neoplasms, Castration-Resistant/drug therapy , Prostatic Neoplasms, Castration-Resistant/pathology , Aged , Aged, 80 and over , Biomarkers, Tumor/blood , Disease-Free Survival , Humans , Male , Middle Aged , Predictive Value of Tests , Prognosis , Prospective Studies , Prostatic Neoplasms, Castration-Resistant/mortality
12.
Asian J Androl ; 21(2): 131-136, 2019.
Article in English | MEDLINE | ID: mdl-30560837

ABSTRACT

This study investigated the clinical activity of abiraterone plus prednisone in docetaxel-naïve and docetaxel-resistant Chinese patients with metastatic castration-resistant prostate cancer (mCRPC). A total of 146 patients with docetaxel-naïve group (103 cases) and docetaxel-resistant group (43 cases) were enrolled from the Shanghai Cancer Center (Shanghai, China) in this retrospective cohort study. The efficacy endpoints were prostate-specific antigen response rate, prostate-specific antigen progression-free survival, clinical/radiographic progression-free survival, and overall survival in response to abiraterone plus prednisone. Significantly higher prostate-specific antigen response rate was found in docetaxel-naïve group (54.4%, 56/103) compared to docetaxel-resistant group (34.9%, 15/43) (P = 0.047). In addition, significantly higher median prostate-specific antigen progression-free survival (14.0 vs 7.7 months, P = 0.005), clinical or radiographic progression-free survival (17.0 vs 12.5 months, P = 0.003), and overall survival (27.0 vs 18.0 months, P = 0.016) were found in docetaxel-naïve group compared to docetaxel-resistant group, respectively. The univariate and multivariate analyses indicated that lower albumin and visceral metastases were independent significant predictors for shorter overall survival. To sum up, our data suggested that abiraterone plus prednisone was efficient in both docetaxel-naïve and docetaxel-resistant Chinese patients. Moreover, higher PSA response rate and longer overall survival were observed in the docetaxel-naïve group, which suggested that abiraterone was more effective for docetaxel- naïve patients than for docetaxel failures.


Subject(s)
Androstenes/therapeutic use , Antineoplastic Agents, Hormonal/therapeutic use , Prednisone/therapeutic use , Prostatic Neoplasms, Castration-Resistant/drug therapy , Aged , Aged, 80 and over , China , Disease Progression , Disease-Free Survival , Drug Therapy, Combination , Humans , Male , Middle Aged , Prostatic Neoplasms, Castration-Resistant/mortality , Retrospective Studies , Survival Rate , Treatment Outcome
13.
Opt Express ; 26(23): 30313-30323, 2018 Nov 12.
Article in English | MEDLINE | ID: mdl-30469906

ABSTRACT

The radiofrequency-optical double magnetic resonance in cesium atoms filled in a vapor cell is investigated experimentally. One resonant signal involving spin-exchange collisions is observed in the MZ type magnetic resonance spectrum. We solve Liouville equations describing the dynamics of the system and analyze the role of the spin-exchange collisions in the atomic population distributions under resonant conditions. The theoretical calculations agree very well with the experimental results. In contrast with the normal magnetic resonance, the collision induced magnetic resonance exhibits the interesting saturation effect: both the signal amplitude and the signal linewidth are nearly constant when the laser intensity is above a moderate threshold value, which can be useful for precision measurements of the geomagnetic field.

14.
Opt Express ; 26(22): 29561-29587, 2018 Oct 29.
Article in English | MEDLINE | ID: mdl-30470118

ABSTRACT

We investigate the radiation properties of a driven exciton-biexciton structure quantum dot placed close to a graphene sheet. The study of the Purcell factor then demonstrates the tunability of light-matter coupling, which in turn provides the possibility to control the steady-state populations. As the result, dipole transitions can be selectively enhanced and asymmetry in the resonance fluorescence can be observed. Meanwhile, both quadratures can exhibit two-mode squeezing at the Rabi sideband frequencies. A further study shows that although the increase in the environment temperature has a destructive influence on the population imbalance, squeezing occurs even at room temperature. Due to the flexibility in controlling the resonance fluorescence spectrum and producing two-mode squeezed states, our proposal would have potential applications in quantum information and other quantum research fields.

15.
J Cancer ; 9(2): 269-274, 2018.
Article in English | MEDLINE | ID: mdl-29344273

ABSTRACT

BACKGROUND: Cytochrome P450 1B1 (CYP1B1) is a key enzyme in its oestrogen metabolism pathway, giving rise to hydroxylation and conjugation. Functionally relevant genetic variants within CYP1B1 may affect the telomere length and subsequently lead to prostate carcinogenesis. METHODS: We evaluated 8 CYP1B1 tag single nucleotide polymorphisms (SNPs) in 1015 men with prostate cancer (PCa) and 1052 cancer-free controls, and calculated odds ratios (ORs) and 95% confidence intervals (CIs) to estimate their association with risk of PCa. The influence of CYP1B1 SNPs on the relative telomere lengths was then appraised in peripheral blood leukocytes using real-time PCR. RESULTS:CYP1B1 rs1056836 variant was associated with decreased risk of PCa [odds ratio (OR): 0.80; 95% confidence interval (CI): 0.68-0.99, P = 0.041]. Longer telomere length showed a significantly higher proportion of the CYP1B1 rs1056836 CG/GG genotypes, compared with that of the CC genotype (OR: 1.60, 95% CI: 1.04-2.45). CONCLUSION: Our findings suggest that genetic variants within CYP1B1 may confer genetic susceptibility to PCa by altering telomere length.

16.
Asian J Androl ; 20(2): 184-188, 2018.
Article in English | MEDLINE | ID: mdl-29111539

ABSTRACT

Abiraterone acetate is approved for the treatment of castration-resistant prostate cancer (CRPC); however, its effects vary. An accurate prediction model to identify patient groups that will benefit from abiraterone treatment is therefore urgently required. The Chi model exhibits a good profile for risk classification, although its utility for the chemotherapy-naive group is unclear. This study aimed to externally validate the Chi model and develop a new nomogram to predict overall survival (OS). We retrospectively analyzed a cohort of 110 patients. Patients were distributed among good-, intermediate-, and poor-risk groups, according to the Chi model. The good-, intermediate-, and poor-risk groups had a sample size of 59 (53.6%), 34 (30.9%), and 17 (15.5%) in our dataset, and a median OS of 48.4, 29.1, and 10.5 months, respectively. The C-index of external validation of Chi model was 0.726. Univariate and multivariate analyses identified low hemoglobin concentrations (<110 g l-1), liver metastasis, and a short time interval from androgen deprivation therapy to abiraterone initiation (<36 months) as predictors of OS. Accordingly, a new nomogram was developed with a C-index equal to 0.757 (95% CI, 0.678-0.836). In conclusion, the Chi model predicted the prognosis of abiraterone-treated, chemotherapy-naive patients with mCRPC, and we developed a new nomogram to predict the overall survival of this group of patients with less parameters.


Subject(s)
Abiraterone Acetate/therapeutic use , Adenocarcinoma/drug therapy , Antineoplastic Agents/therapeutic use , Bone Neoplasms/drug therapy , Liver Neoplasms/drug therapy , Nomograms , Prostatic Neoplasms, Castration-Resistant/drug therapy , Survival Rate , Adenocarcinoma/metabolism , Adenocarcinoma/secondary , Aged , Aged, 80 and over , Alkaline Phosphatase/blood , Androgen Antagonists/therapeutic use , Bone Neoplasms/metabolism , Bone Neoplasms/secondary , Cohort Studies , Humans , Kaplan-Meier Estimate , L-Lactate Dehydrogenase/blood , Liver Neoplasms/metabolism , Liver Neoplasms/secondary , Male , Middle Aged , Multivariate Analysis , Neoplasm Metastasis , Prognosis , Proportional Hazards Models , Prostatic Neoplasms, Castration-Resistant/metabolism , Prostatic Neoplasms, Castration-Resistant/pathology , Retrospective Studies , Serum Albumin/metabolism , Time Factors
17.
J Cancer ; 8(13): 2471-2477, 2017.
Article in English | MEDLINE | ID: mdl-28900484

ABSTRACT

Chemokines are involved in many aspects of oncogenesis, including regulation of cancer cell growth, dissemination and host-tumor response. However, the potential of the chemokine receptors, CXCR4 and CXCR7, in serving as biomarkers in extramammary Paget's disease (EMPD) has been rarely examined. Expressions of CXCR4 and CXCR7 were evaluated in 92 EMPD specimens by immunohistochemistry. High expression of CXCR4 and CXCR7 were both correlated with regional lymph node metastasis and presence of lymphovascular invasion. High expression of CXCR7 also correlated with the depth of invasion. The prognostic value of these two chemokines were also investigated in progression-free survival (PFS) and cancer-specific survival (CSS). Both high expression of CXCR4 and CXCR7 were indicative of shorter PFS and CSS. In the combined prognostic model, concomitant high expression of CXCR4 and CXCR7 were suggestive of poor prognosis compared with the other two groups. In the multivariate analysis, depth of invasion, combined prognostic model and regional lymph node metastasis at diagnosis were the independent prognostic factors for EMPD patients for PFS, and the former two factors independently impacted CSS. Our results demonstrated that CXCR4 and CXCR7 can be used as prognostic biomarkers and prediction of aggressiveness of EMPD. Therapy targeting CXCR4 and CXCR7 may helpful to prevent EMPD progression and improve the prognosis of EMPD.

18.
Opt Express ; 25(6): 6767-6783, 2017 Mar 20.
Article in English | MEDLINE | ID: mdl-28381020

ABSTRACT

In a coherently-driven nanocavity QED system, the one-photon blockade via quantum interference is investigated by the modified Lindblad master equation and without using the secular approximation as well. Based on the dressed bases of the Rabi Hamiltonian, a modified Lindblad master equation is obtained, which is valid for any arbitrary degree of the qubit-cavity interaction. It is found that the damping coefficients are very sensitive to interaction strength between the qubit and the cavity mode. How to enhance the one-photon blockade by using the quantum interference effect is discussed with the generalized second-order correlation function and the second-order perturbation in the five-state truncation of the Hilbert space. It is found that, under suitable pump or detection conditions, a strong one-photon blockade can be realized by completely eliminating the two-photon emission. Moreover, even for a strong cavity damping rate, there exhibits a large number of cavity photons by utilizing the quantum interference mechanism.

19.
Opt Express ; 25(3): 1867-1888, 2017 Feb 06.
Article in English | MEDLINE | ID: mdl-29519039

ABSTRACT

We study the dynamics of two two-level atoms embedded near to the interface of paired meta-material slabs, one of negative permeability and the other of negative permittivity. This combination generates a strong surface plasmon field at the interface between the meta-materials. It is found that the symmetric and antisymmetric modes of the two-atom system couple to the plasmonic field with different Rabi frequencies. Including the Ohmic losses of the materials we find that the Rabi frequencies exhibit threshold behaviour which distinguish between the non-Markovian (memory preserving) and Markovian (memoryless) regimes of the evolution. Moreover, it is found that significantly different dynamics occur for the resonant and an off-resonant couplings of the plasmon field to the atoms. In the case of the resonant coupling, the field does not appear as a dissipative reservoir to the atoms. We adopt the image method and show that the dynamics of the two atoms coupled to the plasmon field are analogous to the dynamics of a four-atom system in a rectangular configuration. A large and long living entanglement mediated by the plasmonic field in both Markovian and non-Markovian regimes of the evolution is predicted. We also show that a simultaneous Markovian and non-Markovian regime of the evolution may occur in which the memory effects exist over a finite evolution time. In the case of an off-resonant coupling of the atoms to the plasmon field, the atoms interact with each other by exchanging virtual photons which results in the dynamics corresponding to those of two atoms coupled to a common reservoir. In addition, the entanglement is significantly enhanced.

20.
Opt Express ; 24(12): 13590-609, 2016 Jun 13.
Article in English | MEDLINE | ID: mdl-27410375

ABSTRACT

We propose a scheme for generation of a nonlinear coherent state (NCS) of a mechanical resonator (MR) in an optomechanical micro-cavity, in which a two-level quantum dot (QD) and the microcavity are respectively driven by a strong laser and a weak laser. This microcavity can be engineered within a photonic band-gap (PBG) material. By properly tuning the frequency of the weak driving field, two-photon blockade phenomenon occurs. The QD-cavity subsystem can evolve into a dark state due to the damping of the microcavity and the elimination of the decay rate of the QD at selected frequencies in the PBG material. In this situation, the phonon mode of the MR can be prepared into a NCS, which is a non-classical state and possesses the sub-Poisson statistics. We also demonstrate the Wigner function of the NCS, which negativity implies its non-classicality.

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