Practical effects in the preparation of cluster states using weak non-linearities

We discuss experimental effects in the implementation of a recent scheme for performing bus mediated entangling operations between qubits. Here a bus mode, a strong coherent state, successively undergoes weak Kerr-type non-linear interactions with qubits. A quadrature measurement on the bus then projects the qubits into an entangled state. This approach has the benefit that entangling gates are non-destructive, may be performed non-locally, and there is no need for efficient single photon detection. In this paper we examine practical issues affecting its experimental implementation. In particular, we analyze the effects of post-selection errors, qubit loss, bus loss, mismatched coupling rates and mode-mismatch. We derive error models for these effects and relate them to realistic fault-tolerant thresholds, providing insight into realistic experimental requirements.Comment: 8 pages, 5 figure

Investigating the Operational Issue and Potential Demand of Airport Bus Service at Minangkabau International Airport

Minangkabau International Airport (BIM) has been operating almost a decade and currently BIM can be visited using the airport bus provided by the City Government of Padang. Although the airport bus service is available, BIM visitors generally tend to choose private vehicles, such as cars or motorcycles. Considering the energy crisis and the negative impact of traffic, visitors are expected to shift to the airport bus, because the bus is more sustainable mode of transportation. However, this policy needs to be supported with sufficient information so that the target to be achieved can be realized. This study aimed to investigate factors that prevent visitors to use the airport bus and try to predict the potential demands. The results obtained from this study show that only 19 % of BIM visitors choose an airport bus as a mode of transportation. Other modes are selected because of some uncertainty on the airport bus service, which involves schedules and bus stop locations. In addition, a number of respondents did not even know of the existence of the airport bus service. If these problems can be solved, the potential airport bus users are predicted to reach 58 % of the total number of BIM visitors

Long-range coupling of silicon photonic waveguides using lateral leakage and adiabatic passage

We present a new approach to long range coupling based on a combination of adiabatic passage and lateral leakage in thin shallow ridge waveguides on a silicon photonic platform. The approach enables transport of light between two isolated waveguides through a mode of the silicon slab that acts as an optical bus. Due to the nature of the adiabatic protocol, the bus mode has minimal population and the transport is highly robust. We prove the concept and examine the robustness of this approach using rigorous modelling. We further demonstrate the utility of the approach by coupling power between two waveguides whilst bypassing an intermediate waveguide. This concept could form the basis of a new interconnect technology for silicon integrated photonic chips

Low error measurement-free phase gates for qubus computation

We discuss the desired criteria for a two-qubit phase gate and present a method for realising such a gate for quantum computation that is measurement-free and low error. The gate is implemented between qubits via an intermediate bus mode. We take a coherent state as the bus and use cross-Kerr type interactions between the bus and the qubits. This new method is robust against parameter variations and is thus low error. It fundamentally improves on previous methods due its deterministic nature and the lack of approximations used in the geometry of the phase rotations. This interaction is applicable both to solid state and photonic qubit systems.Comment: 6 pages, 4 figures. Published versio

A conditional quantum phase gate between two 3-state atoms

We propose a scheme for conditional quantum logic between two 3-state atoms that share a quantum data-bus such as a single mode optical field in cavity QED systems, or a collective vibrational state of trapped ions. Making use of quantum interference, our scheme achieves successful conditional phase evolution without any real transitions of atomic internal states or populating the quantum data-bus. In addition, it only requires common addressing of the two atoms by external laser fields.Comment: 8 fig

Simulations of vertically-coupled microdisk-resonators by 3-D vectorial coupled mode theory

Fully vectorial 3D frequency-domain simulations of vertically coupled integrated-optical microdisk-resonators are described. The 'rigorous' coupled mode theory model combines numerically computed bend modes of the cavity disk and guided modes of the straight bus waveguides

High fidelity quantum gates of trapped ions mediated by a dissipative bus mode

We describe the optimal realization of entangling quantum gates for trapped ions mediated by a dissipative bus mode. With suitably shaped control pulses one can substantially decrease ion-phonon entanglement while maintaining the mediated interaction

Multicomputer communication system

A local area network is provided for a plurality of autonomous computers which operate at different rates and under different protocols coupled by network bus adapters to a global bus. A host computer (HC) divides a message file to be transmitted into blocks, each with a header that includes a data type identifier and a trailer. The associated network bus adapter (NBA) then divides the data into packets, each with a header to which a transport header and trailer is added with frame type code which specifies one of three modes of addressing in the transmission of data, namely a physical address mode for computer to computer transmission using two bytes for source and destination addresses, a logical address mode and a data type mode. In the logical address mode, one of the two addressing bytes contains a logical channel number (LCN) established between the transmitting and one or more receiving computers. In the data type mode, one of the addressing bytes contains a code identifying the type of data

An HCMT model of optical microring-resonators

Analytical modes of the bus and cavity cores are combined into a 2-D hybrid analytical / numerical coupled mode theory (HCMT) model of integrated optical ring-resonators. The variational technique generates 1-D FEM-discretized solutions for the amplitude functions in their natural Cartesian and polar coordinates