Observation of correlated-photon statistics using a single detector

We report experimental observations of correlated-photon statistics in the single-photon detection rate. The usual quantum interference in a two-photon polarization interferometer always accompanies a dip in the single detector counting rate, regardless of whether a dip or peak is seen in the coincidence rate. This effect is explained by taking into account all possible photon number states that reach the detector, rather than considering just the state post-selected by the coincidence measurement. We also report an interferometeric scheme in which the interference peak or dip in coincidence corresponds directly to a peak or dip in the single-photon detection rate.Comment: 4 pages, two-column (minor errors corrected.

A glance of child’s play privacy in smart toys

© Springer International Publishing AG 2016. A smart toy is defined as a device consisting of a physical toy component that connects to one or more toy computing services to facilitate gameplay in the Cloud through networking and sensory technologies to enhance the functionality of a traditional toy. A smart toy in this context can be effectively considered an Internet of Things (IoT) with Artificial Intelligence (AI) which can provide Augmented Reality (AR) experiences to users. Referring to the direction of the United States Federal Trade Commission Children’s Online Privacy Protection Act (COPPA) and the European Union Data Protection Directive (EUDPD), this study adopts the definition of a child to be an individual under the age of 13 years old. In this study, the first assumption is that children do not understand the concept of privacy. The second assumption is that children will disclose as much information to smart toys as they can trust. Breaches of privacy can result in physical safety of child user, e.g., child predators. While the parents/legal guardians of a child strive to ensure their child’s physical and online safety and privacy, there is no common approach for these parents/guardians to study the information flow between their child and the smart toys they interact with. This paper discusses related privacy requirements for smart toys in a toy computing environment with a case study on a commercial smart toy called Hello Barbie from Mattel

Intelligent multi-agent collaboration model for smart home IoT security

© 2018 IEEE. While the Internet of Things (IoT) continue to extend deeper into the daily lives of people, the domain of the smart home offers a unique need for security. Traditional firewalls and antivirus are not sufficient to protect the connected home from security threats, and to date, there have been limited solutions provided for this problem. This paper explores the recent works in this area and presents a new approach towards securing smart home networks through multi-agent collaboration. The model uses Beliefs, Desires, and Intentions (BDI) architecture for intelligent agent decision making, as well as a multi-agent collaboration model for achieving mutual security goals within the smart home network. For initial proof of concept, we provide a use case demonstrating the coordination of the threat response decision between operational availability and security risk agents as a qualitative coalitional game. This model can also be extended to other areas such as threat modeling, vulnerability scanning, and patching, as well as more advanced threat engagement and distraction. Throughout, we also consider operational goals of convenience and availability as required for a usability perspective within the smart home environment

Experimental observation of nonclassical effects on single-photon detection rates

It is often asserted that quantum effects can be observed in coincidence detection rates or other correlations, but never in the rate of single-photon detection. We observe nonclassical interference in a singles rate, thanks to the intrinsic nonlinearity of photon counters. This is due to a dependence of the effective detection efficiency on the quantum statistics of the light beam. Such measurements of detector response to photon pairs promise to shed light on the microscopic aspects of silicon photodetectors, and on general issues of quantum measurement and decoherence.Comment: 8 pages, 4 figure

``Electric growth`` of metal overlayers on semiconductor substrates

In this article, the authors present the main results from their recent studies of metal overlayer growth on semiconductor substrates. They show that a variety of novel phenomena can exist in such systems, resulting from several competing interactions. The confined motion of the conduction electrons within the metal overlayer can mediate a surprisingly long-range repulsive force between the metal-semiconductor interface and the growth front, acting to stabilize the overlayer. Electron transfer from the overlayer to the substrate leads to an attractive force between the two interfaces, acting to destabilize the overlayer. Interface-induced Friedel oscillations in electron density can further impose an oscillatory modulation onto the two previous interactions. These three competing factors, of all electronic nature, can make a flat metal overlayer critically, marginally, or magically stable, or totally unstable against roughening. The authors further show that, for many systems, these electronic effects can easily win over the effect of stress. First-principles studies of a few representative systems support the main features of the present electronic growth concept

A study of children facial recognition for privacy in smart TV

© Springer International Publishing AG 2017. Nowadays Smart TV is becoming very popular in many families. Smart TV provides computing and connectivity capabilities with access to online services, such as video on demand, online games, and even sports and healthcare activities. For example, Google Smart TV, which is based on Google Android, integrates into the users’ daily physical activities through its ability to extract and access context information dependent on the surrounding environment and to react accordingly via built-in camera and sensors. Without a viable privacy protection system in place, however, the expanding use of Smart TV can lead to privacy violations through tracking and user profiling by broadcasters and others. This becomes of particular concern when underage users such as children who may not fully understand the concept of privacy are involved in using the Smart TV services. In this study, we consider digital imaging and ways to identify and properly tag pictures of children in order to prevent unwanted disclosure of personal information. We have conducted a preliminary experiment on the effectiveness of facial recognition technology in Smart TV where experimental recognition of child face presence in feedback image streams is conducted through the Microsoft’s Face Application Programming Interface

Quantum interference with beamlike type-II spontaneous parametric down-conversion

We implement experimentally a method to generate photon-number$-$path and polarization entangled photon pairs using ``beamlike'' type-II spontaneous parametric down-conversion (SPDC), in which the signal-idler photon pairs are emitted as two separate circular beams with small emission angles rather than as two diverging cones.Comment: 4 pages, two-colum

Spectroscopy by frequency entangled photon pairs

Quantum spectroscopy was performed using the frequency-entangled broadband photon pairs generated by spontaneous parametric down-conversion. An absorptive sample was placed in front of the idler photon detector, and the frequency of signal photons was resolved by a diffraction grating. The absorption spectrum of the sample was measured by counting the coincidences, and the result is in agreement with the one measured by a conventional spectrophotometer with a classical light source.Comment: 11 pages, 5 figures, to be published in Phys. Lett.

Demonstration of Feed-Forward Control for Linear Optics Quantum Computation

One of the main requirements in linear optics quantum computing is the ability to perform single-qubit operations that are controlled by classical information fed forward from the output of single photon detectors. These operations correspond to pre-determined combinations of phase corrections and bit-flips that are applied to the post-selected output modes of non-deterministic quantum logic devices. Corrections of this kind are required in order to obtain the correct logical output for certain detection events, and their use can increase the overall success probability of the devices. In this paper, we report on the experimental demonstration of the use of this type of feed-forward system to increase the probability of success of a simple non-deterministic quantum logic operation from approximately 1/4 to 1/2. This logic operation involves the use of one target qubit and one ancilla qubit which, in this experiment, are derived from a parametric down-conversion photon pair. Classical information describing the detection of the ancilla photon is fed-forward in real-time and used to alter the quantum state of the output photon. A fiber optic delay line is used to store the output photon until a polarization-dependent phase shift can be applied using a high speed Pockels cell

A Mach-Zehnder Interferometer for a Two-Photon Wave Packet

We propose an experiment that permits observation of the de Broglie two-photon wave packet behavior for a pair of photons, using a Mach-Zehnder interferometer. It is based on the use of pulsed lasers to generate pairs of photons via spontaneous parametric down-conversion and the post-selection of events. It differs from previous realizations by the use of a third time-correlated photon to engineer the state of the photons. The same technique can give us which-path information via an ``interaction-free'' experiment and can be used in other experiments on the foundations of quantum mechanics related to wave-particle duality and to nonlocality.Comment: Submmited for publication in Physical Review