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Full-Text Articles in Physics
Optically Simulating A Quantum Associative Memory, John C. Howell, John A. Yeazell, Dan Ventura
Optically Simulating A Quantum Associative Memory, John C. Howell, John A. Yeazell, Dan Ventura
Mathematics, Physics, and Computer Science Faculty Articles and Research
This paper discusses the realization of a quantum associative memory using linear integrated optics. An associative memory produces a full pattern of bits when presented with only a partial pattern. Quantum computers have the potential to store large numbers of patterns and hence have the ability to far surpass any classical neural-network realization of an associative memory. In this work two three-qubit associative memories will be discussed using linear integrated optics. In addition, corrupted, invented and degenerate memories are discussed.
Nondestructive Single-Photon Trigger, John C. Howell, John A. Yeazell
Nondestructive Single-Photon Trigger, John C. Howell, John A. Yeazell
Mathematics, Physics, and Computer Science Faculty Articles and Research
A triggering device sensitive to a single photon is discussed. It is based on a balanced quantum nondemolition (QND) measurement proposed by Chuang and Yamamoto [Phys. Rev. Lett. 76, 4281 (1996)]. The balanced measurement measures the total photon number and obtains no which-path/mode information. Hence, the timing of the photon can be determined without destroying its wave function or entangling the probe field. This could have extensive use in the realization of long-distance quantum communications systems.
Quantum Computation Through Entangling Single Photons In Multipath Interferometers, John C. Howell, John A. Yeazell
Quantum Computation Through Entangling Single Photons In Multipath Interferometers, John C. Howell, John A. Yeazell
Mathematics, Physics, and Computer Science Faculty Articles and Research
Single-photon interferometry has been used to simulate quantum computations. Its use has been limited to studying few-bit applications due to rapid growth in physical size with numbers of bits. We propose a hybrid approach that employs n photons, each having L degrees of freedom yielding Ln basis states. The photons are entangled via a quantum nondemolition measurement. This approach introduces the essential element of quantum computing, that is, entanglement into the interferometry. Using these techniques, we demonstrate a controlled-NOT gate and a Grover's search circuit. These ideas are also applicable to the study of nonlocal correlations in many dimensions.
Entangling Macroscopic Quantum States, John C. Howell, John A. Yeazell
Entangling Macroscopic Quantum States, John C. Howell, John A. Yeazell
Mathematics, Physics, and Computer Science Faculty Articles and Research
Spatial entanglements of macroscopic quantum systems are proposed. The which-path uncertainty of a single photon passing through a beam splitter is transformed into the which-path uncertainty of two macroscopic fields via two quantum nondemolition measurements. The macroscopic fields are nonlocally correlated.
Reducing The Complexity Of Linear Optics Quantum Circuits, John C. Howell, John A. Yeazell
Reducing The Complexity Of Linear Optics Quantum Circuits, John C. Howell, John A. Yeazell
Mathematics, Physics, and Computer Science Faculty Articles and Research
Integrated optical elements can simplify the linear optics used to simulate quantum circuits. These linear optical simulations of quantum circuits have been developed primarily in terms of the free space optics associated with single-photon interferometry. For an L-bit simulation the number of required free-space optical elements is ∝2L if 50/50 beam splitters are used. The implementation (construction and alignment) of these circuits with these free-space elements is nontrivial. On the other hand, for the cases presented in this paper in which linear integrated optics (e.g., 2L×2L fiber couplers) are used, the number of optical devices does …