This PDF file contains the front matter associated with SPIE Proceedings Volume 10984, including the Title Page, Copyright Information, Table of Contents, Author and Conference Committee lists.

We discuss the properties of quantum state reactivity as a measure for quantum correlation. This information geometry-based definition is a generalization of the two qubit construction of Schumacher to multipartite quantum states. It requires a generalization of information distance to information areas as well as to higher-dimensional volumes. The reactivity is defined in the usual chemistry way as a ratio of surface area to volume. The reactivity is an average over all detector settings. We show that this measure posses the key features required for a measure of quantum correlation. We show that it is invariant under local unitary transformations, non{increasing under local operations and classical communication, and monotonic. Its maximum bound can't be obtained using only classical correlation. Furthermore, reactivity is an analytic function of measurement probabilities and easily extendable to higher multipartite states.

Quantum field is back at the headlines with several research areas such as: quantum sensing, quantum communication, quantum cryptography and quantum computing. A novel concept of a computer exploiting quantum confinement and nonlinear optics is the basis of an EC H2020 consortium named COPAC [1,2,3]. We joined this consortium which uses the dynamic response of assembled nanostructures in solid arrays short laser pulses and implement a novel paradigm for parallel information processing. Within current paper we will discuss the nanostructures materials and configurations as designed for the project, especially the interaction of the nanostructures with the addressing laser beam unit.

The DNA molecule can be modeled as a quantum logic processor in which electron spin qubits are held coherently in each nucleotide in a logically and thermodynamically reversible enantiomeric symmetry, and can be coherently conducted along the pi-stacking interactions of aromatic nucleotide bases, while simultaneously being spin-filtered via the helicity of the DNA molecule. Entangled electron pairs can be separated by that spin-filtering, held coherently at biological temperatures in the topologically insulated nucleotide quantum gates, and incorporated into separate DNA strands during DNA replication. Two separate DNA strands that share quantum entangled electrons can be mitotically divided into individual cells, and thus into two individual cell cultures. Initial experiments to validate the quantum DNA model have shown correlations in the depolarizations between separated cloned neuronal cell cultures, and additional investigations are indicated for further validation.

Interferometric stability of polarization-entangled photons in quantum repeaters for long time intervals is an important capability for future scalable quantum networks linked over distances greater than hundreds of kilometers. A quantum memory node is a necessary component of the quantum repeater, where entanglement is prepared and swapped to extend entangled states from remote to distant nodes. Room temperature fluctuations can have significant effects on phase stability of the polarization states stored in the quantum memory. Although common-path stabilization in a quantum memory has been demonstrated, passive stabilization to room temperature variations has not been realized. Our approach to the quantum memory uses a single collective excitation encoded in two separate spatial modes in a cold ensemble of rubidium atoms. The two spatial modes are combined into a single path using the birefringence of two calcite crystals. However, normal lab temperature changes introduces a phase shift between the ordinary and extraordinary pathways on the order of 2π. We demonstrate passive temperature stabilization by alignment of the ordinary path in one crystal to the extraordinary path in the second crystal and vice versa. We show a phase stability on the order of ten hours by homodyne detection of classical light modes exiting the interferometer. We corroborate the phase stability of the quantum memory with a correlation measurement between polarization states of a signal photon generated at the formation of the collective atomic excitation and a retrieved idler photon during the destruction of the atomic excitation. We measure a Bell-CHSH parameter for both the unstable configuration and for the stable configuration. For an unstable calcite crystal configuration, we do not measure a violation of the Bell-CHSH inequality¹ (S≤2) with S = 1.42 ± 0.087. For the stable calcite crystal configuration, we measure a violation of Bell-CHSH inequality (S>2) with S = 2.48±0.099.

Quantum technologies containing key GaN laser components will enable a new generation of precision sensors, optical atomic clocks and secure communication systems for many applications such as next generation navigation, gravity mapping and timing since the AlGaInN material system allows for laser diodes to be fabricated over a wide range of wavelengths from the u.v. to the visible.

We introduce the NIST Platform for Quantum Network Innovation (PQNI) – a new testbed on the NIST campus to accelerate the integration of quantum systems into a real life, active network in a controlled scientific setting. The testbed will be used to evaluate quantum scale devices and components such as single photon sources, detectors, memories and interfaces within various quantum network protocols and configurations for performance, optimization, synchronization, loss compensation, error correction, compatibility with conventional network traffic (often referred to as co-existence), continuity of operations and more.

We demonstrate a novel quantum key distribution scheme whose implementation utilizes multi-spectral bistability states to encode information. The transition between states is triggered optically. This makes it an all-optical system for ease of implementation in optical networks. We shall present an QKD architecture based on this scheme, and discuss its security and robustness against attacks.

For dynamically-reconfigurable wireless optical communication, quantum optical communication and interfacing, as well as quantum processing, we research integrated microelectronic and photonic solutions. We investigate fundamental paradigms and scalable technologies. Optical waveguides support interfacing, ultra-dense quadrature amplitude modulation, multiplexing and demultiplexing, quantum state mixing and conversion, switching, etc. The silicon nitride is nonlinear media which exhibit nonlinear electro-optical, magneto-optical, optical and quantum effects. To accomplish measurable and processable transductions on physical variables which realize processing schemes, we investigate integration and role of passive and active components, such as controlled lasers, quantum dots, photon detectors, etc. Our objective is to find engineering silicon photonics for quantum-enabled processing and communication. Information science, quantum mechanics and nonlinear optics paradigms are applied. Analytic and low-fidelity experimental studies are reported.

In 2001, Michael Berry4 published the paper ”Knotted Zeros in the Quantum States of Hydrogen” in Foundations of Physics. In this paper we show how to place Berry’s discovery in the context of general knot theory and in the context of our formulations for quantum knots. Berry gave a time independent wave function for hydrogen, as a map from three space R³ to the complex plane and such that the inverse image of 0 in the complex plane contains a knotted curve in R³. We show that for knots in R³ this is a generic situation in that every smooth knot K in R³ has a smooth classifying map f : R³ −→ C (the complex plane) such that f⁻¹(0) = K. This leaves open the question of characterizing just when such f are wave-functions for quantum systems. One can compare this result with the work of Mark Dennis and his collaborators and with the work of Lee Rudolph. Our approach provides great generality to the structure of knotted zeros of a wavefunction and opens up many new avenues for research in the relationships of quantum theory and knot theory. We show how this classifying construction can be related our previous work on two dimensional and three dimensional mosaic and lattice quantum knots.

We continue our discusson on quantum knots and knotted zeroes, further discussing relationships with mosaic and lattice quantum knots.

The unexpected plays an important but little-understood role in physics. We are working to understand how the unexpected functions in theory and in experiment. This work leads to novel theoretical and instrumental structures of “two-clock physics”, with implications for the scientific method. The path to these structures that express the unexpected draws on three roots: 1. Physicists write strings of symbols. Quantum theory implies that physicists act as agents who make guesses, expressed as strings of symbols, in the face of unpredictability far more drastic than quantum uncertainty. Assimilating unpredictability as pervasive in theory and experiment opens new avenues to investigation. 2. No two clocks tick alike. We formulate a concept network of transmission of symbols among agents, without assuming any spacetime or any global time variable, but requiring that agents adjust local clock rates. This structure offers alternatives to time and distance adapted to a variety of cases and is an important element of what we call two-clock physics. 3. Sometimes a flipped coin lands on edge. Agents must rely on guesses to steer clock rates to achieve a logical synchronization that avoids confusion of one symbol with another.

Indefinite causal ordering (ICO) refers to quantum channels arranged so that the path through them is a super- position of different possible paths. The ICO is called pure when the path superposition is a pure quantum state. Channel probing, in which probes in prepared quantum states are passed through copies of the channel to estimate one or more channel parameters, is aided by ICO. Specifically, pure ICO is known to increase the quantum Fisher information (QFI) in the processed probe state about the unknown parameter(s). We consider the case complementary to pure ICO in which the path state is maximally mixed for a given indefiniteness. Deriving the QFI under this condition by a new approach, we find that mixed ICO-assisted probing, while not as beneficial as pure ICO probing, still yields greater QFI than does the comparable scheme with definite causal order. The d-dimensional quantum depolarizing channel is used as the channel model for this study. While mixed ICO-assisted probing, like pure ICO-assisted probing, is generally advantageous for probing the depolarizing channel, mixed ICO's relative effectiveness decreases with probe dimension, just as for pure ICO-assisted probing, each being most effective for qubit probes.

Quantum information science aims to revolutionize existing methods for manipulating data by utilizing the unique features of nonclassical physical phenomena. This control is realized over several platforms, one particular being photonics which employs state of the art fabrication techniques that achieve integrated nanocircuit components. The Hong-Ou-Mandel effect underlies the basic entangling mechanism of linear optical quantum computing, and is a critical feature in the design of nanophotonic circuits used for quantum information processing. We will present some results from an on-chip Hong-Ou-Mandel (HOM) experiment that replaces the conventional beam splitter with a more compact and highly versatile ring resonator allowing greater functionality with an expanded parameter space dubbed Hong-Ou-Mandel Manifold (HOMM). The overarching goal of this work is to demonstrate on-chip, scalable, dynamically configurable quantum-optical interconnects for integration into photonic quantum information processing devices.

A sensor based on quantum multiphoton entanglement (ME) combined with hyper-entanglement (HE) is described. Measures of effectiveness (MOEs) are derived describing the benefits of forming hybrid states between ME and HE. An open systems approach is taken with both environmental noise and loss factors included. Methods of generating the ME and HE states are described with schematics provided. Networks are introduced yielding additional performance improvements. Waveforms for effective atmospheric propagation are discussed. A new parameterized mode is derived using Lie algebra techniques. The waveform is shown to be a scaled and translated form of the Airy wave. The additional scaling and translation parameters derived from Lie algebra theory show promise for selecting the best performing waveform or linear combination of such waveforms. Alternatively, parameters for single waveforms or linear combinations of parameterized Airy waves can be selected through optimization. An MOE, the Holevo bound, is maximized ultimately yielding the Holevo-Shumacher-Westmoreland capacity. Analysis of the translated and scaled Airy function show that its asymptotic form yields much less loss during atmospheric propagation. It is robust under turbulence and atmospheric inhomogeneities. Additional parameters in the argument of the Airy function that occur as a natural result of the derivation show promise for using the waveform to facilitate imaging around corners. Second quantization is applied resulting in a version of the waveform when only one signal photon is present for entangled or non-entangled systems. Even when only one signal photon is propagating the waveform is shown to have advantages for sensing and imaging.

Methods of improving quantum LADARs and related sensors are developed based on quantum entanglement and hyperentanglement. Multiple single photon states are used to obtain a multiphoton entangled state. These states can be N00N states, M&N states (M&N), or a linear combination of M&N states (LCMNS) or generalized states kindred to LCMNS. The procedure for doing this derives from the fundamental theorem of algebra. Various states generated by this process are developed. A diagram of a device for producing such states is examined. They are related to a simpler version of this concept introduced in the seminal experiment by Mitchell-Lundeen and Steinberg. A certain class of states obtained through the Schrodinger kitten process are shown to be effective for generating states hyper-entangled in polarization and energy-time. A diagram of a device for producing such states is considered. Alternate methods of generating hyperentanglement in polarization and energy-time are discussed. Improvements offered by networks are discussed. The utility of these procedures for sensing and communications is examined. An open systems analysis based on density operator theory is conducted including both noise and loss mechanisms. The susceptibility to noise and loss of the various hyper-entanglement procedures is examined. Various measures of effectiveness (MOEs) are derived to quantize system performance. MOEs include but are not limited to, SNR, signal-to-interference ratio, quantum Cramer Rao’ lower bound, quantum Chernoff bound, measurement time, the Holevo bound, sensing range, and resolution. A summary table with expanded MOEs results drawing from multiple papers is provided.

We show that when the integration time of the single photon detectors is longer than the correlation time of the biphoton, the attainable spatial resolution in ghost imaging with entangled signal idler pairs generated in type II spontaneous parametric down conversion is limited by the angular spread of single-frequency-signal idler pairs. If, however, the detector integration time is shorter than the biphoton correlation time, the transverse k-vectors of different spectral components combine coherently in the image, improving the spatial resolution.

Unitary operations using linear optics have many applications within the quantum and neuromorphic space. In silicon photonics, using networks of simple beam splitters and phase shifters have proven sufficient to realize large-scale arbitrary unitaries. While this technique has shown success with high fidelity, the grid physically scales with an upper bound of O(n²). Consequently, we propose to considerably reduce the footprint by using multimode interference (MMI) devices. In this paper, we investigate the active control of these MMIs and their suitability for approximating traditionally used unitary circuits.