Quantum key distribution and 1 Gbit/s data encryption over a single fibre

We perform quantum key distribution (QKD) in the presence of 4 classical channels in a C-band dense wavelength division multiplexing (DWDM) configuration using a commercial QKD system. The classical channels are used for key distillation and 1 Gbps encrypted communication, rendering the entire system independent from any other communication channel than a single dedicated fibre. We successfully distil secret keys over fibre spans of up to 50 km. The separation between quantum channel and nearest classical channel is only 200 GHz, while the classical channels are all separated by 100 GHz. In addition to that we discuss possible improvements and alternative configurations, for instance whether it is advantageous to choose the quantum channel at 1310 nm or to opt for a pure C-band configuration.Comment: 9 pages, 7 figure

Detector dead-time effects and paralyzability in high-speed quantum key distribution

Recent advances in quantum key distribution (QKD) have given rise to systems that operate at transmission periods significantly shorter than the dead times of their component single-photon detectors. As systems continue to increase in transmission rate, security concerns associated with detector dead times can limit the production rate of sifted bits. We present a model of high-speed QKD in this limit that identifies an optimum transmission rate for a system with given link loss and detector response characteristics

Quantum key distribution with 1.25 Gbps clock synchronization

We have demonstrated the exchange of sifted quantum cryptographic key over a 730 meter free-space link at rates of up to 1.0 Mbps, two orders of magnitude faster than previously reported results. A classical channel at 1550 nm operates in parallel with a quantum channel at 845 nm. Clock recovery techniques on the classical channel at 1.25 Gbps enable quantum transmission at up to the clock rate. System performance is currently limited by the timing resolution of our silicon avalanche photodiode detectors. With improved detector resolution, our technique will yield another order of magnitude increase in performance, with existing technology.Comment: 6 pages, 3 figures, 99 kB .pdf documen

Falling into Time in Homer's Iliad

This paper addresses the question of the relation between mortal and immortal time in the Iliad as it is represented by the physical act of falling. I begin by arguing that falling serves as a point of reference throughout the poem for a concept of time that is specifically human. It is well known that mortals fall at the moment of death in the poem, but it has not been recognized that the movement of the fall is also connected with the time of birth, aging, and generation. In light of the significance of failing for mortals, I then go on to examine the problematic case of two particular immortals who fall in the Iliad. When Hephaestus tumbles down to earth from Olympus. and when Ares is knocked flat on the battlefield, both gods, I argue, also "fall into" human time. This complicates their status as ageless and eternal beings, and draws into question the different temporal registers at work in the narrative (such as repetition, "long time," and time that is steady or continuous [empedos]). The single action of failing brings together several key concepts in the poem which hinge on the issue of the separation between the mortal and immortal spheres in the Iliad

Prosodic contrasts in ironic speech

Prosodic features in spontaneous speech help disambiguate implied meaning not explicit in linguistic surface structure, but little research has examined how these signals manifest themselves in real conversations. Spontaneously produced verbal irony utterances generated between familiar speakers in conversational dyads were acoustically analyzed for prosodic contrasts. A prosodic contrast was defined as a statistically reliable shift between adjacent phrasal units in at least 1 of 5 acoustic dimensions (mean fundamental frequency, fundamental frequency variability, mean amplitude, amplitude variability, and mean syllable duration). Overall, speakers contrasted prosodic features in ironic utterances with utterances immediately preceding them at a higher rate than between adjacent nonironic utterance pairs from the same interactions. Across multiple speakers, ironic utterances were spoken significantly slower than preceding speech, but no other acoustic dimensions changed consistently. This is the first acoustic analysis examining relative prosodic changes in spontaneous ironic speech. Prosodic contrasts are argued to be an important mechanism for communicating implicit emotional and intentional information in speech-and a means to understanding traditional notions of an ironic tone. © Taylor & Francis Group, LLC

When is irony influenced by communicative constraints? ERP

First published: 07 July 2019Distinct theoretical proposals have described how communicative constraints (contextual biases, speaker identity) impact verbal irony processing. Modular models assume that social and contextual factors have an effect at a late stage of processing. Interactive models claim that contextual biases are considered early on. The constraint‐ satisfaction model further assumes that speaker's and context's characteristics can compete at early stages of analysis. The present ERP study teased apart these models by testing the impact of context and speaker features (i.e., speaker accent) on irony analysis. Spanish native speakers were presented with Spanish utterances that were ironic or literal. Each sentence was preceded by a negative or a positive context. Each story was uttered in a native or a foreign accent. Results showed that contextual biases and speaker accent interacted as early as 150 ms during irony processing. Greater N400‐like effects were reported for ironic than literal sentences only with positive contexts and native accent, possibly suggesting semantic difficulties when non‐prototypical irony was produced by natives. A P600 effect of irony was also reported indicating inferential processing costs. The results support the constraintsatisfaction model and suggest that multiple sources of information are weighted and can interact from the earliest stages of irony analysis.Spanish State Research Agency (Severo Ochoa excellence accreditation), Grant/ Award Number: SEV‐2015‐0490; the Basque Government, Grant/Award Number: BERC 2018–2021, PI_2015_1_25; Spanish Ministry of Economy and Competitiveness, Grant/Award Number: PSI2014‐54500, PSI2017‐82941‐P, IJCI‐2016‐27702; Grant/Award Number: H2020‐MSCA‐IF‐2018‐837228. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 837228

Is there an Ironic Tone of Voice?

Research on nonverbal vocal cues and verbal irony has often relied on the concept of an ironic tone of voice. Here we provide acoustic analysis and experimental evidence that this notion is oversimplified and misguided. Acoustic analyses of spontaneous ironic speech extracted from talk radio shows, both ambiguous and unambiguous in written form, revealed only a difference in amplitude variability compared to matched nonironic speech from the same sources, and that was only among the most clear-cut items. In a series of experiments, participants rated content-filtered versions of the same ironic and nonironic utterances on a range of affective and linguistic dimensions. Listeners did not rely on any set of vocal cues to identify verbal irony that was separate from other emotional and linguistic judgments. We conclude that there is no particular ironic tone of voice and that listeners interpret verbal irony by combining a variety of cues, including information outside of the linguistic context. © Kingston Press Ltd