Enhancing qubit readout through dissipative sub-Poissonian dynamics

Single-shot qubit readout typically combines high readout contrast with long-lived readout signals, leading to large signal-to-noise ratios and high readout fidelities. In recent years, it has been demonstrated that both readout contrast and readout signal lifetime, and thus the signal-to-noise ratio, can be enhanced by forcing the qubit state to transition through intermediate states. In this work, we demonstrate that the sub-Poissonian relaxation statistics introduced by intermediate states can reduce the single-shot readout error rate by orders of magnitude even when there is no increase in signal-to-noise ratio. These results hold for moderate values of the signal-to-noise ratio ($\mathcal{S} \lesssim 100$) and a small number of intermediate states ($N \lesssim 10$). The ideas presented here could have important implications for readout schemes relying on the detection of transient charge states, such as spin-to-charge conversion schemes for semiconductor spin qubits and parity-to-charge conversion schemes for topologically protected Majorana qubits.Comment: 10 pages, 6 figures. Two appendices have been added. This version is close to the final published versio

Holding Canada's Cities to Account: an Assessment of Municipal Fiscal Management

Cities are the most visible level of government for most Canadians, providing services such as waste collection, policing and transit. Yet their budgets are the most opaque of any level of government. Municipalities generally use accounting in their budgets that does not match what they use in their financial reports. Peering through the messy numbers reveals that most cities routinely miss budget targets by large amounts. Councillors and taxpayers who seek to hold these municipal governments to account face a daunting task. Amid the mixed record, however, are some municipalities with clearer numbers and better records for spending control. That fact, along with improvements that have occurred at the federal and provincial levels in recent years, shows that progress is possible. The authors suggest five basic reforms would create clearer, more consistent budgets and would bring the financial management of Canada’s municipalities into line with their fiscal impact and their importance in Canadians’ lives.Fiscal & Tax Competitiveness, Governance and Public Institutions, Urban Issues Series, Canadian municipalities, fiscal management, municipal budgets

Americans’ Perceptions of Food Safety: A Comparative Study on Fresh Produce and Meat Products

Crop Production/Industries,

Quadrilateral-octagon coordinates for almost normal surfaces

Normal and almost normal surfaces are essential tools for algorithmic 3-manifold topology, but to use them requires exponentially slow enumeration algorithms in a high-dimensional vector space. The quadrilateral coordinates of Tollefson alleviate this problem considerably for normal surfaces, by reducing the dimension of this vector space from 7n to 3n (where n is the complexity of the underlying triangulation). Here we develop an analogous theory for octagonal almost normal surfaces, using quadrilateral and octagon coordinates to reduce this dimension from 10n to 6n. As an application, we show that quadrilateral-octagon coordinates can be used exclusively in the streamlined 3-sphere recognition algorithm of Jaco, Rubinstein and Thompson, reducing experimental running times by factors of thousands. We also introduce joint coordinates, a system with only 3n dimensions for octagonal almost normal surfaces that has appealing geometric properties.Comment: 34 pages, 20 figures; v2: Simplified the proof of Theorem 4.5 using cohomology, plus other minor changes; v3: Minor housekeepin