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An Architectural Perspective on Digital Quantum Switching
Published in Anwar Sohail, Raja M Yasin Anwar Akhtar, Raja Qazi Salahuddin, Ilyas Mohammad, Nanotechnology for Telecommunications, 2017
The basic information carrier in quantum information science is a two-level quantum bit—qubit. In a two-level quantum system, each bit can be represented using a basis consisting of two eigenstates, denoted by |0〉 and |1〉. These states can be either spin states of a particle (|0〉 for spin-up and |1〉 for spin-down) or energy levels in an atom (|0〉 for ground state and |1〉 for excited state). These two states can be used to simulate the classical binary logic. A classical binary logic value must be either ON (1) or OFF (0), but not both at the same time. However, a bit in a quantum system can be any linear combination of these two states. The state |ϕ〉 of a quantum bit can be written as
An Overview of Future Applications of Quantum Computing
Published in Thiruselvan Subramanian, Archana Dhyani, Adarsh Kumar, Sukhpal Singh Gill, Artificial Intelligence, Machine Learning and Blockchain in Quantum Satellite, Drone and Network, 2023
Taskeen Zaidi, Bijjahalli Sadanandamurthy Sushma
Quantum computing is also applied in other scientific domains such as quantum information science, quantum communication, quantum physics and quantum metrology. All these technologies transform the quantum system. Quantum science applied the encoding of information in a quantum system. It used all the statistics of quantum mechanics and its limitations. Quantum mechanics is the core of other applications like quantum computing, communications, networking and metrology.
Precise positioning of an ion in an integrated Paul trap-cavity system using radiofrequency signals
Published in Journal of Modern Optics, 2018
Ezra Kassa, Hiroki Takahashi, Costas Christoforou, Matthias Keller
The field of atomic physics has advanced greatly since the advent of ion traps which confine ions for unprecedented durations without utilising the internal states of the ions. Because ion traps offer unparalleled levels of control over the ions’ mechanical and internal degrees of freedom, many experiments have sought to combine them with optical cavities for enhanced atom-light interactions. As a result, there have been a number of significant experiments: single photons were generated on demand [1], cavity sideband cooling was performed on single ions [2], super-radiance was observed with the collective coupling of coulomb crystals [3], tunable ion-photon entanglement has been demonstrated [4], multiple ions have been deterministically coupled to a cavity [5]. The combination of ion traps with optical cavities is also considered to be one of the most promising avenues for advances in quantum information processing. Whilst there has been remarkable progress in the preparation, gate operation and readout of qubits [6,7], to date, these implementations have been limited to small scales, with 14 being the largest number of qubits entangled [8]. Presently, challenges in the physical implementations of large quantum systems pose the greatest difficulty in advancing experimental quantum information science. Among the proposed solutions to tackle the scalability problem (e.g. [9–12]), distributed quantum information processing based on photonic links is the most promising. Notably, modular approaches using trapped ions as stationary qubits have attracted significant interest. However, so far, optically heralded entanglement with remote trapped ions has only been demonstrated using high numerical aperture lenses for the collection of photons, a method which suffers from low efficiencies in the entanglement generation[13,14]. Placing the ions in an optical cavity, this efficiency can be greatly enhanced. Further, by reducing the cavity mode volume, one can enhance the ion-cavity coupling and, subsequently, the efficiency of operations. To this end, fiber-based Fabry-Pérot cavities (FFPCs) have been combined with ion traps [15–17]. In such ion trap-cavity systems, the optimal positioning of the ion with respect to the cavity mode is of vital importance. In the previously demonstrated designs of ion traps combining FFPCs [15–17], the FFPCs were mechanically translated to optimise the overlap between the ion and the cavity mode. In addition to the need for a three-dimensional positioning system which tends to be bulky and expensive, the movable cavities affect the trapping field and shift the geometrical center of the trap as they are moved. This adds complexity to the trapping and optimisation of the ion-cavity coupling.