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| Author | Gustafsson, Martin V.; Santos, Paulo V.; Johansson, Göran; Delsing, Per | ||||
| Title | Local probing of propagating acoustic waves in a gigahertz echo chamber | Type | Journal Article | ||
| Year | 2012 | Publication | Nature Physics | Abbreviated Journal | Nat. Phys. |
| Volume | 8 | Issue | 4 | Pages | 338-343 |
| Keywords | fromIPMRAS | ||||
| Abstract | In the same way that micro-mechanical resonators resemble guitar strings and drums, surface acoustic waves resemble the sound these instruments produce, but moving over a solid surface rather than through air. In contrast with oscillations in suspended resonators, such propagating mechanical waves have not before been studied near the quantum mechanical limits. Here, we demonstrate local probing of surface acoustic waves with a displacement sensitivity of 30amRMSHz-1/2 and detection sensitivity on the single-phonon level after averaging, at a frequency of 932MHz. Our probe is a piezoelectrically coupled single-electron transistor, which is sufficiently fast, non-destructive and localized to enable us to track pulses echoing back and forth in a long acoustic cavity, self-interfering and ringing the cavity up and down. We project that strong coupling to quantum circuits will enable new experiments, and hybrids using the unique features of surface acoustic waves. Prospects include quantum investigations of phonon-phonon interactions, and acoustic coupling to superconducting qubits for which we present favourable estimates. | ||||
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| Call Number | RPLAB @ gujma @ | Serial | 813 | ||
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| Author | Korotkov, Alexander N. | ||||
| Title | Entanglement preservation: The Sleeping Beauty approach | Type | Journal Article | ||
| Year | 2012 | Publication | Nature Physics | Abbreviated Journal | Nat. Phys. |
| Volume | 8 | Issue | 2 | Pages | 107-108 |
| Keywords | fromIPMRAS | ||||
| Abstract | Two-qubit entanglement can be preserved by partially measuring the qubits to leave them in a 'lethargic' state. The original state is restored using quantum measurement reversal after the qubits have travelled through a decoherence channel. | ||||
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| Call Number | RPLAB @ gujma @ | Serial | 814 | ||
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| Author | Kim, Yong-Su; Lee, Jong-Chan; Kwon, Osung; Kim, Yoon-Ho | ||||
| Title | Protecting entanglement from decoherence using weak measurement and quantum measurement reversal | Type | Journal Article | ||
| Year | 2012 | Publication | Nature Physics | Abbreviated Journal | Nat. Phys. |
| Volume | 8 | Issue | 2 | Pages | 117-120 |
| Keywords | fromIPMRAS | ||||
| Abstract | Decoherence, often caused by unavoidable coupling with the environment, leads to degradation of quantum coherence. For a multipartite quantum system, decoherence leads to degradation of entanglement and, in certain cases, entanglement sudden death. Tackling decoherence, thus, is a critical issue faced in quantum information, as entanglement is a vital resource for many quantum information applications including quantum computing, quantum cryptography, quantum teleportation and quantum metrology. Here, we propose and demonstrate a scheme to protect entanglement from decoherence. Our entanglement protection scheme makes use of the quantum measurement itself for actively battling against decoherence and it can effectively circumvent even entanglement sudden death. | ||||
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| Call Number | RPLAB @ gujma @ | Serial | 815 | ||
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| Author | Bason, Mark G.; Viteau, Matthieu; Malossi, Nicola; Huillery, Paul; Arimondo, Ennio; Ciampini, Donatella; Fazio, Rosario; Giovannetti, Vittorio; Mannella, Riccardo; Morsch, Oliver | ||||
| Title | High-fidelity quantum driving | Type | Journal Article | ||
| Year | 2012 | Publication | Nature Physics | Abbreviated Journal | Nat. Phys. |
| Volume | 8 | Issue | 2 | Pages | 147-152 |
| Keywords | fromIPMRAS | ||||
| Abstract | Accurately controlling a quantum system is a fundamental requirement in quantum information processing and the coherent manipulation of molecular systems. The ultimate goal in quantum control is to prepare a desired state with the highest fidelity allowed by the available resources and the experimental constraints. Here we experimentally implement two optimal high-fidelity control protocols using a two-level quantum system comprising Bose-Einstein condensates in optical lattices. The first is a short-cut protocol that reaches the maximum quantum-transformation speed compatible with the Heisenberg uncertainty principle. In the opposite limit, we realize the recently proposed transitionless superadiabatic protocols in which the system follows the instantaneous adiabatic ground state nearly perfectly. We demonstrate that superadiabatic protocols are extremely robust against control parameter variations, making them useful for practical applications. | ||||
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| Call Number | RPLAB @ gujma @ | Serial | 816 | ||
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| Author | Pernice, W.; Schuck, C.; Minaeva, O.; Li, M.; Goltsman, G. N.; Sergienko, A. V.; Tang, H. X. | ||||
| Title | High speed and high efficiency travelling wave single-photon detectors embedded in nanophotonic circuits | Type | Miscellaneous | ||
| Year | 2012 | Publication | arXiv | Abbreviated Journal | arXiv |
| Volume | 1108.5299 | Issue | Pages | 1-23 | |
| Keywords | optical waveguides, waveguide SSPD, guantum photonics, jitter, detection efficiency | ||||
| Abstract | Ultrafast, high quantum efficiency single photon detectors are among the most sought-after elements in modern quantum optics and quantum communication. High photon detection efficiency is essential for scalable measurement-based quantum computation, quantum key distribution, and loophole-free Bell experiments. However, imperfect modal matching and finite photon absorption rates have usually limited the maximum attainable detection efficiency of single photon detectors. Here we demonstrate a superconducting nanowire detector atop nanophotonic waveguides which allows us to drastically increase the absorption length for incoming photons. When operating the detectors close to the critical current we achieve high on-chip single photon detection efficiency up to 91% at telecom wavelengths, with uncertainty dictated by the variation of the waveguide photon flux. We also observe remarkably low dark count rates without significant compromise of detection efficiency. Furthermore, our detectors are fully embedded in a scalable silicon photonic circuit and provide ultrashort timing jitter of 18ps. Exploiting this high temporal resolution we demonstrate ballistic photon transport in silicon ring resonators. The direct implementation of such a detector with high quantum efficiency, high detection speed and low jitter time on chip overcomes a major barrier in integrated quantum photonics. | ||||
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Approved | no | |||
| Call Number | Serial | 845 | |||
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| Author | Shurakov, Alexander; Tong, Edward; Blundell, Raymond; Gol'tsman, Gregory | ||||
| Title | Microwave stabilization of HEB mixer by a microchip controller | Type | Conference Article | ||
| Year | 2012 | Publication | IEEE MTT-S international microwave symposium digest | Abbreviated Journal | |
| Volume | Issue | Pages | 1-3 | ||
| Keywords | HEB mixer stability, microwave injection, Allan variance, Allan time | ||||
| Abstract | The stability of a Hot Electron Bolometer (HEB) mixer can be improved by the use of microwave injection. In this article we report a refinement of this approach. We introduce a microchip controller to facilitate the implementation of the stabilization scheme, and demonstrate that the feedback loop effectively suppresses drifts in the HEB bias current, leading to an improvement in the receiver stability. The measured Allan time of the mixer's IF output power is increased to > 10 s. | ||||
| Address | Montreal, QC, Canada | ||||
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| Call Number | Serial | 857 | |||
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| Author | Henrich, D.; Dorner,S.; Hofherr, M.; Il'in, K.; Semenov, A.; Heintze, E.; Scheffler, M.; Dressel, M.; Siegel, M. | ||||
| Title | Broadening of hot-spot response spectrum of superconducting NbN nanowire single-photon detector with reduced nitrogen content | Type | Journal Article | ||
| Year | 2012 | Publication | Abbreviated Journal | J. Appl. Phys. | |
| Volume | 112 | Issue | Pages | ||
| Keywords | SSPD, SNSPD, magnetron sputtering, spectrum, NbN film, nitrogen concentration | ||||
| Abstract | The spectral detection efficiency and the dark count rate of superconducting nanowire single-photon detectors (SNSPD) have been studied systematically on detectors made from thin NbN films with different chemical compositions. Reduction of the nitrogen content in the 4 nm thick NbN films results in a decrease of the dark count rates more than two orders of magnitude and in a red shift of the cut-off wavelength of the hot-spot SNSPD response. The observed phenomena are explained by an improvement of uniformity of NbN films that has been confirmed by a decrease of resistivity and an increase of the ratio of the measured critical current to the depairing current. The latter factor is considered as the most crucial for both the cut-off wavelength and the dark count rates of SNSPD. Based on our results we propose a set of criteria for material properties to optimize SNSPD in the infrared spectral region. VC 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4757625] |
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| Corporate Author | D. Henrich, S. Dorner, M. Hofherr, K. Il'in, A. Semenov, E. Heintze, M. Scheffler, M. Dressel, M. Siegel | Thesis | |||
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| Language | English | Summary Language | Original Title | Broadening of hot-spot response spectrum of superconducting NbN nanowire single-photon detector with reduced nitrogen content | |
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Approved | no | |||
| Call Number | RPLAB @ seleznev @ | Serial | 877 | ||
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| Author | Inderbitzin, K.; Engel, A.; Schilling, A.; Il'in, K.; Siegel, M. | ||||
| Title | An ultra-fast superconducting Nb nanowire single-photon detector for soft x-rays | Type | Journal Article | ||
| Year | 2012 | Publication | Abbreviated Journal | Appl. Phys. Lett. | |
| Volume | 101 | Issue | Pages | ||
| Keywords | SSPD, SNSPD, x-ray, Nb | ||||
| Abstract | Although superconducting nanowire single-photon detectors (SNSPDs) are well studied regarding the detection of infrared/optical photons and keV-molecules, no studies on continuous x-ray photon counting by thick-film detectors have been reported so far. We fabricated a 100 nm thick niobium x-ray SNSPD (an X-SNSPD) and studied its detection capability of photons with keV-energies in continuous mode. The detector is capable to detect photons even at reduced bias currents of 0.4%, which is in sharp contrast to optical thin-film SNSPDs. No dark counts were recorded in extended measurement periods. Strikingly, the signal amplitude distribution depends significantly on the photon energy spectrum.VC |
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Approved | no | |||
| Call Number | RPLAB @ seleznev @ | Serial | 878 | ||
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| Author | D. Henrich, L. Rehm S. Dörner, M. Hofherr, K. Il'in, A. Semenov, and M. Siegel | ||||
| Title | Detection efficiency of a spiral-nanowire superconducting single-photon detector | Type | Journal Article | ||
| Year | 2012 | Publication | Abbreviated Journal | ||
| Volume | Issue | Pages | |||
| Keywords | Critical current, Nanoscale devices, Superconducting photodetectors. | ||||
| Abstract | We investigate the detection efficiency of a spiral layout of a Superconducting Nanowire Single-Photon Detector (SNSPD). The design is less susceptible to the critical current reduction in sharp turns of the nanowire than the conventional meander design. Detector samples with different nanowire width from 300 to 100 nm are patterned from a 4 nm thick NbN film deposited on sapphire substrates. The critical current IC at 4.2 K for spiral, meander, and simple bridge structures is measured and compared. On the 100 nm wide samples, the detection efficiency is measured in the wavelength range 400-1700 nm and the cut-off wavelength of the hot-spot plateau is determined. In the optical range, the spiral detector reaches a detection efficiency of 27.6%, which is ~1.5 times the value of the meander. In the infrared range the detection efficiency is more than doubled. | ||||
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| Corporate Author | D. Henrich, L. Rehm S. Dörner, M. Hofherr, K. Il'in, A. Semenov, and M. Siegel | Thesis | |||
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Approved | no | |||
| Call Number | RPLAB @ seleznev @ | Serial | 880 | ||
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| Author | Julia Toussaint, Roman Grüner, Marco Schubert, Torsten May, Hans-Georg Meyer, Benjamin Dietzek, Jürgen Popp, Matthias Hofherr, Matthias Arndt, Dagmar Henrich, Konstantin Il'in, and Michael Siegel | ||||
| Title | Superconducting single-photon counting system for optical experiments requiring time-resolution in the picosecond range | Type | Journal Article | ||
| Year | 2012 | Publication | Abbreviated Journal | AIP REVIEW OF SCIENTIFIC INSTRUMENTS | |
| Volume | 83 | Issue | Pages | ||
| Keywords | SSPD, picosecond, time-resolution | ||||
| Abstract | We have developed a cryogenic measurement system for single-photon counting, which can be used in optical experiments requiring high time resolution in the picosecond range. The system utilizes niobium nitride superconducting nanowire single-photon detectors which are integrated in a timecorrelated single-photon counting (TCSPC) setup. In this work, we describe details of the mechanical design, the electrical setup, and the cryogenic optical components. The performance of the complete system in TCSPC mode is tentatively benchmarked using 140 fs long laser pulses at a repetition frequency of 75MHz. Due to the high temporal stability of these pulses, the measured time resolution of 35 ps (FWHM) is limited by the timing jitter of the measurement system. The result was crosschecked in a Coherent Anti-stokes Raman Scattering (CARS) setup, where scattered pulses from a β-barium borate crystal have been detected with the same time resolution. |
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Approved | no | |||
| Call Number | RPLAB @ seleznev @ | Serial | 885 | ||
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