Geometric entanglement of a photon and spin qubits in diamond

Geometric nature, which appears in photon polarization, also appears in spin polarization under a zero magnetic field. These two polarized quanta, one travelling in vacuum and the other staying in matter, behave the same as geometric quantum bits or qubits, which are promising for noise resilience compared to the commonly used dynamic qubits. Here we show that geometric photon and spin qubits are entangled upon spontaneous emission with the help of the spin − orbit entanglement inherent in a nitrogen-vacancy center in diamond. The geometric spin qubit is defined in a degenerate subsystem of spin triplet electrons and manipulated with a polarized microwave. An experiment shows an entanglement state fidelity of 86.8%. The demonstrated entangled emission, combined with previously demonstrated entangled absorption, generates purely geometric entanglement between remote matters in a process that is insensitive of time, frequency, and space mode matching, which paves the way for building a noise-resilient quantum repeater network or a quantum internet.

Programmable quantum simulator boasts up to 256 qubits

Physicists have demonstrated a largescale, programmable quantum simulator that features a 2D array of 256 quantum bits (qubits).

Conjectural schema using Quantum mechanics-AI to express and interpret emotional intellect in a social robot

In this paper, the study represents a theoretical conceptualization on the potential improvements to interpret and devise under the notion of quantum mechanics & AI utilizing psychology for social robots. The framework is elaborated in regard to the development of emotions encoded through information and possibilities, which manipulates the use of transitions of these emotions in states through the Quantum & AI measurements. To support the development, work introduced is an interpretation of quantum mechanics, linked with quantum science, systems science, and Conceptualized Neural Network. The understanding of these emotions are expected to impact the technical capability of robots in a specific aspect to sense, capture, and act in an environment relied on optimization of quantum bits, where a robot, perform these emotions through a network which will allow interaction with the given target, changing the robot’s state of response according to optimization and gates from target itself, computing the robot’s emotional performance based on measurement and mathematical expressions changing in accordance to the available information. This method will help to emphasize its viability and effectiveness in the synthesis of emotional intellect in social robots.

Bell Diagonal and Werner State Generation: Entanglement, Non-Locality, Steering and Discord on the IBM Quantum Computer

We propose the first correct special-purpose quantum circuits for preparation of Bell diagonal states (BDS), and implement them on the IBM Quantum computer, characterizing and testing complex aspects of their quantum correlations in the full parameter space. Among the circuits proposed, one involves only two quantum bits but requires adapted quantum tomography routines handling classical bits in parallel. The entire class of Bell diagonal states is generated, and several characteristic indicators, namely entanglement of formation and concurrence, CHSH non-locality, steering and discord, are experimentally evaluated over the full parameter space and compared with theory. As a by-product of this work, we also find a remarkable general inequality between “quantum discord” and “asymmetric relative entropy of discord”: the former never exceeds the latter. We also prove that for all BDS the two coincide.

Highly tunable magneto-optical response from magnesium-vacancy color centers in diamond

Defect quantum bits (qubits) constitute an important emerging technology. However, it is necessary to explore new types of defects to enable large-scale applications. In this article, we examine the potential of magnesium-vacancy (MgV) in diamond to operate as a qubit by computing the key electronic- and spin properties with robust theoretical methods. We find that the electronic structure of MgV permits the coexistence of two loosely separated spin-states, where both can emerge as a ground state and be interconverted depending on the temperature and external strain. These results demonstrate a route to control the magneto-optical response of a qubit by modulating the operational conditions.

Quantum Signal over Optical Fiber

This chapter aims to address the quantum signal role and properties in optical fiber application mainly in quantum communication. It covers the general discussion on quantum bits and optical waveguiding properties. The highlight of this chapter lies in the discussion of the quantum fictitious force of anti-centrifugal force which was first reported in 2001. Under this condition, the free particle experience an attractive potential towards the rotating center of a bent waveguide structure. A lot of theoretical work has been carried out to observe this quantum phenomenon. However, no intensive experimental work has been carried out to date. With the advancement of nano-fabrication technology and quantum experimental, it provides a bright potential to observe these phenomena. Thus, we proposed a promising material of Lithium Niobate on Insulator to serve as a waveguiding platform to study this quantum effect experimentally. The discussion is extended to perceive the relation between Schrodinger and Helmholtz’s equation corresponding to this effect.