A scheme for amplification and discrimination of photons

A scheme for exploring photon number amplification and discrimination is presented based on the interaction of a large number of two-level atoms with a single mode radiation field. The fact that the total number of photons and atoms in the excited states is a constant under time evolution in Dicke model is exploited to rearrange the atom-photon numbers. Three significant predictions emerge from our study: Threshold time for initial exposure to photons, time of perception (time of maximum detection probability), and discrimination of first few photon states.Comment: 8 pages, 3 figures, RevteX, Minor revision, References adde

Quantum reading of digital memory with non-Gaussian entangled light

It has been shown recently (Phys. Rev. Lett. 106, 090504 (2011)) that entangled light with Einstein-Podolsky-Rosen (EPR) correlations retrieves information from digital memory better than any classical light. In identifying this, a model of digital memory with each cell consisting of reflecting medium with two reflectivities (each memory cell encoding the binary numbers 0 or 1) is employed. The readout of binary memory essentially corresponds to discrimination of two Bosonic attenuator channels characterized by different reflectivities. The model requires an entire mathematical paraphernalia of continuous variable Gaussian setting for its analysis, when arbitrary values of reflectivities are considered. Here we restrict to a basic quantum read-out mechanism with non-Gaussian entangled states of light, with the binary channels to be discriminated being ideal memory characterized by reflectivity one i.e., an identity channel and thermal noise channel, where the signal light illuminating the memory location gets completely lost (zero reflectivity) and only a white thermal noise hitting the upper side of the memory reaches the decoder. We compare the quantum reading efficiency of entangled light with any classical source of light in this model. We show that entangled transmitters offer better reading performance than any classical transmitters of light in the regime of low signal intensity.Comment: 7 pages, 6 figures, To appear in Phys. Rev.

Nonlinear Mixing of Laser Generated Narrowband Rayleigh Surface Waves

This study presents the nonlinear mixing technique of two co-directionally travelling Rayleigh surface waves generated and detected using laser ultrasonics. The optical generation of Rayleigh waves on the specimen is obtained by shadow mask method. In conventional nonlinear measurements, the inherently small higher harmonics are greatly influenced by the nonlinearities caused by coupling variabilities and surface roughness between the transducer and specimen interface. The proposed technique is completely contactless and it should be possible to eliminate this problem. Moreover, the nonlinear mixing phenomenon yields not only the second harmonics, but also the sum and difference frequency components, which can be used to measure the acoustic nonlinearity of the specimen. In this paper, we will be addressing the experimental configurations for this technique and characterize the acoustic nonlinearity of the specimen through measuring the nonlinearity parameter ‘β’. The proposed technique is validated experimentally on Aluminum 7075 alloy specimen

Joint Measurability and Temporal Steering

Quintino et. al. (Phys. Rev. Lett. 113, 160402 (2014)) and Uola et. al. (Phys. Rev. Lett. 113, 160403 (2014)) have recently established an intrinsic relation between non-joint measurability and Einstein-Podolsky- Rosen steering. They showed that a set of measurements is incompatible (i.e., not jointly measurable) if and only if it can be used for the demonstration of steering. In this paper, we prove the temporal analog of this result viz., a set of measurements are incompatible if and only if it exhibits temporal steering.Comment: 6 pages,no figures, typos corrected, improved presentation; To appear in JOSA B feature issue "80 years of Steering and the Einstein-Podolsky-Rosen Paradox

Subwavelength Resolution of Cracks in the Metallic Materials

In recent years, various types of acoustic metamaterials have been proposed with capabilities for overcoming the diffraction limit. However, typically such developments only consider the acoustic regime [1] or imaging in liquid media [2]. In this paper we demonstrate the application of a holey structured metamaterial lens for sub-wavelength imaging of defects in a metallic sample, in the ultrasonic regime. Finite Element (FE) simulations are used to study longitudinal wave interaction with ideal cracks in isotropic elastic materials. Holey-structured meta-lenses are then used to transmit the scattered waves. We experimentally demonstrate a subwavelength resolution of λ/7 with a sub-wavelength notch in an aluminium block, which to the best of our knowledge this is the highest resolution achieved in the ultrasonic regime

Smart and secure medical device gateway for managing patient recovery

Patients recuperating from orthopedic surgery require frequent monitoring and hospital visits with a wealth of personal medical data generated both on and off-site, making it challenging to maintain records. This paper discusses a secure blockchain-based data management software to enable safe remote access without compromising patient information. The BlockTrack software developed at our group will be customized to interface with modules for orthopedic recuperation monitoring. Modules can consist of ultrasonic bone health monitoring sensors, connected to relay nodes that can transmit patient data to the BlockTrack mobile app, which then intercepts the information to be stored securely on a cloud-based Blockchain network. Each record will have a unique ID enabled by Blockchain, for secure access and review of patient information by other parties, including doctors and pharmacists. Key findings are discussed with a goal to further develop this solution

Guided ultrasonic wave monitoring techniques to assess bone implant loosening

Total ankle replacement (TAR) is the main clinical treatment for end-stage ankle arthritis, replacing the ankle joint with a metallic implant. Component loosening, fracture, and wear are the main reasons for implant failure, requiring revision surgery. A non-invasive guided wave monitoring technique is being developed to ultimately evaluate in-vivo implant device integrity and bone-implant interface conditions (osseointegration). Finite Element (FE) simulations were performed to investigate the feasibility and sensitivity of ultrasonic monitoring of the interface conditions, assessing suitable guide d wave modes and excitation frequencies. A simplified implant geometry was developed for FE modelling in Abaqus/Explicit. Selected guided wave modes (higher-order longitudinal modes sensitive to bone/implant interface changes) were excited at the distal end of the metallic implant component for detection of variations of bone-implant contact conditions. Simulation results showed the feasibility for guided ultrasonic waves to monitor bone implant osseointegration. Guided wave signal amplitude and changes of arrival time of pulses propagating along the metallic implant can indicate the presence of improved osseointegration. The potential for the integration of the bone implant monitoring sensors and other biosensors into secure, blockchain-based, remote patient data management systems will be further investigated

N′-[(1E)-4-Diethyl­amino-2-hy­droxy­benz­idene]benzohydrazide

In the title compound, C18H21N3O2, the dihedral angle between the phenyl and benzene rings is 36.85 (10)°. The methyl C atom of one of the ethyl groups is disordered over two positions with site occupancies of 0.810 (8) and 0.190 (8). The mol­ecular structure is stabilized by a classical intra­molecular O—H⋯N hydrogen bond. The crystal structure exhibits weak inter­molecular N—H⋯O, C—H⋯O and C—H⋯π inter­actions