RENT: Notes on Efficiency Pricing, Rent Control and Monopolistic Landlords

We consider a model of 'tenancy rent control' where landlords are not allowed to raise the rent on sitting tenants nor to evict them, though they are free to set the nominal rent when taking on a new tenant. If there is any inflation in the economy, landlords prefer to take shortstaying tenants. Assuming that there is no way for landlords to tell a tenant's type, an adverse selection problem arises. If in this context, landlords have monopoly power--which, as we argue, is indeed pervasive--then the housing market equilibria can exhibit some unexpected properties. Most strikingly, landlords may prefer not to raise the rent even when there is excess demand for housing. Such rents are labeled "efficiency rents" in this paper and their existence shows that tenancy rent control can give rise to equilibria which look as it there were traditional rent control in which the rent of each unit has a flat ceiling. In other words, tenancy rent control may not achieve the flexibility, which it was expected to impart, to the system of traditional rent control.

On the Deployment of Cognitive Relay as Underlay Systems

The objective of this paper is to extend the idea of Cognitive Relay (CR). CR, as a secondary user, follows an underlay paradigm to endorse secondary usage of the spectrum to the indoor devices. To seek a spatial opportunity, i.e., deciding its transmission over the primary user channels, CR models its deployment scenario and the movements of the primary receivers and indoor devices. Modeling is beneficial for theoretical analysis, however it is also important to ensure the performance of CR in a real scenario. We consider briefly, the challenges involved while deploying a hardware prototype of such a system.Comment: 6 pages, 7 figures, 4 tables, accepted in Proceedings of CrownCom 2014, Oulu (Finland), June 2-4, 201

Unconstrained Capacities of Quantum Key Distribution and Entanglement Distillation for Pure-Loss Bosonic Broadcast Channels

We consider quantum key distribution (QKD) and entanglement distribution using a single-sender multiple-receiver pure-loss bosonic broadcast channel. We determine the unconstrained capacity region for the distillation of bipartite entanglement and secret key between the sender and each receiver, whenever they are allowed arbitrary public classical communication. A practical implication of our result is that the capacity region demonstrated drastically improves upon rates achievable using a naive time-sharing strategy, which has been employed in previously demonstrated network QKD systems. We show a simple example of the broadcast QKD protocol overcoming the limit of the point-to-point strategy. Our result is thus an important step toward opening a new framework of network channel-based quantum communication technology.Comment: 9 pages, 5 figure

Unconstrained distillation capacities of a pure-loss bosonic broadcast channel

Bosonic channels are important in practice as they form a simple model for free-space or fiber-optic communication. Here we consider a single-sender two-receiver pure-loss bosonic broadcast channel and determine the unconstrained capacity region for the distillation of bipartite entanglement and secret key between the sender and each receiver, whenever they are allowed arbitrary public classical communication. We show how the state merging protocol leads to achievable rates in this setting, giving an inner bound on the capacity region. We also evaluate an outer bound on the region by using the relative entropy of entanglement and a `reduction by teleportation' technique. The outer bounds match the inner bounds in the infinite-energy limit, thereby establishing the unconstrained capacity region for such channels. Our result could provide a useful benchmark for implementing a broadcasting of entanglement and secret key through such channels. An important open question relevant to practice is to determine the capacity region in both this setting and the single-sender single-receiver case when there is an energy constraint on the transmitter.Comment: v2: 6 pages, 3 figures, introduction revised, appendix added where the result is extended to the 1-to-m pure-loss bosonic broadcast channel. v3: minor revision, typo error correcte

Bounds on entanglement distillation and secret key agreement for quantum broadcast channels

The squashed entanglement of a quantum channel is an additive function of quantum channels, which finds application as an upper bound on the rate at which secret key and entanglement can be generated when using a quantum channel a large number of times in addition to unlimited classical communication. This quantity has led to an upper bound of $\log((1+\eta)/(1-\eta))$ on the capacity of a pure-loss bosonic channel for such a task, where $\eta$ is the average fraction of photons that make it from the input to the output of the channel. The purpose of the present paper is to extend these results beyond the single-sender single-receiver setting to the more general case of a single sender and multiple receivers (a quantum broadcast channel). We employ multipartite generalizations of the squashed entanglement to constrain the rates at which secret key and entanglement can be generated between any subset of the users of such a channel, along the way developing several new properties of these measures. We apply our results to the case of a pure-loss broadcast channel with one sender and two receivers.Comment: 35 pages, 1 figure, accepted for publication in IEEE Transactions on Information Theor