Quantum gambling using mesoscopic ring qubits

Mesoscopic entanglement of noninteracting qubits using collective spontaneous emission

We describe anexperimentally straightforward method for preparing an entangled W state of at least 100 qubits. Our repeat-until-success protocol relies on detection of single photons from collective spontaneous emission in free space. Our method allows entanglement preparation in a wide range of qubit implementations that lack entangling qubit–qubit interactions. We give detailed numerical exam...

Ring-shaped nanomagnets: from quantum effects to spin-cluster qubits

Quantum dense coding using three qubits

We consider a situation in which two parties, Alice and Bob, share a 3-qubit system coupled in an initial maximally entangled, GHZ state. By manipulating locally two of the qubits, Alice can prepare any one of the eight 3-qubit GHZ states. Thus the sending of Alice’s two qubits to Bob, entails 3 bits of classical information which can be recovered by Bob by means of a measurement distinguishing...

Conditional quantum logic using two atomic qubits

Type-II Quantum computing Using superconducting Qubits

Most algorithms designed for quantum computers will not best their classical counterparts until they are implemented with thousands of qubits. For example, the factoring of binary numbers with a quantum computer is estimated to be faster than a classical computer only when the length of the number is greater than about 500 digits [1]. In contrast, the Factorized Quantum Lattice-Gas Algorithm (F...