Adiabatic quantum computing is an analogue quantum computing scheme with various applications in solving optimisation problems. In the parity picture of quantum optimization, the problem is encoded in local fields that act on qubits that are connected via local four-body terms We present an implementation of a parity annealer with Transmon qubits with a specifically tailored Ising interaction from Josephson ring modulators.
In view of real-world applications of quantum information technologies, the combination of miniature quantum resources with existing fibre networks is a crucial issue. Among such resources, on-chip entangled photon sources play a central role for applications spanning quantum communications, computing and metrology. Here, we use a semiconductor source of entangled photons operating at room temperature in conjunction with standard telecom components to demonstrate multi-user quantum key distribution, a core protocol for securing communications in quantum networks. The source consists of an AlGaAs chip-emitting polarisation entangled photon pairs over a large bandwidth in the main telecom band around 1550 nm without the use of any off-chip compensation or interferometric scheme; the photon pairs are directly launched into a dense wavelength division multiplexer (DWDM) and secret keys are distributed between several pairs of users communicating through different channels. We achiev…
Although there are several space telescopes currently in operation, most people may think that the iconic Hubble Space Telescope is the way that they should all appear. Not so! Multiple alternative future designs for space observatories have been pro
Analysis from a new galaxy survey suggests that dark matter may be less dense and more smoothly distributed throughout space than previously thought; and in spite of the Schiaparelli crash earlier this year, the ESA approves funding for ExoMars rover
What is a Dark Galaxy? How do astronomers detect a galaxy that has almost no stars and is composed almost entirely of Dark Matter? Join today’s Astro Coffee Hangout to find out! Sponsor: .SPACE Domains
On November 2, 2016 NASA announced that the assembly for the James Webb Space Telescope is now complete. Tony and Carol give a summary of where the mission is now and what’s in store for 2017.
Astronomers using the Very Large Telescope at the European Southern Observatory see something that may confirm that the vacuum of space is not empty; and The Laser Interferometer Gravitational Wave Observatory, or LIGO, gets an upgrade.
We will explore how the resources in place on Mars will make possible long-term human exploration of the Red Planet’s surface.
Quantum random number generators (QRNG) represent an advanced solution for randomness generation, which is essential in every cryptographic application. In this context, integrated arrays of single-photon detectors have promising applications as QRNGs based on the spatial detection of photons. For the employment of QRNGs in cryptography, it is necessary to have efficient methods to evaluate the so-called quantum min-entropy that corresponds to the amount of the true extractable quantum randomness from the QRNG. Here, we present an efficient method that allows the estimation of the quantum min-entropy for a multi-detector QRNG. In particular, we consider a scenario in which an attacker can control the efficiency of the detectors and knows the emitted number of photons. Eventually, we apply the method to a QRNG with 10 3 detectors.