Showing papers by "Yu. A. Pashkin published in 2010"
TL;DR: The behavior of the artificial atom, a superconducting macroscopic two-level system, is in a quantitative agreement with the predictions of quantum optics for a pointlike scatterer interacting with the electromagnetic field in one-dimensional open space.
Abstract: An atom in open space can be detected by means of resonant absorption and reemission of electromagnetic waves, known as resonance fluorescence, which is a fundamental phenomenon of quantum optics. We report on the observation of scattering of propagating waves by a single artificial atom. The behavior of the artificial atom, a superconducting macroscopic two-level system, is in a quantitative agreement with the predictions of quantum optics for a pointlike scatterer interacting with the electromagnetic field in one-dimensional open space. The strong atom-field interaction as revealed in a high degree of extinction of propagating waves will allow applications of controllable artificial atoms in quantum optics and photonics.
599 citations
TL;DR: The observed almost 100% modulation of the reflection and transmission of propagating microwaves demonstrates full controllability of individual artificial atoms and a possibility to manipulate the atomic states.
Abstract: We present experimental observation of electromagnetically induced transparency (EIT) on a single macroscopic artificial "atom" (superconducting quantum system) coupled to open 1D space of a transmission line. Unlike in an optical media with many atoms, the single-atom EIT in 1D space is revealed in suppression of reflection of electromagnetic waves, rather than absorption. The observed almost 100% modulation of the reflection and transmission of propagating microwaves demonstrates full controllability of individual artificial atoms and a possibility to manipulate the atomic states. The system can be used as a switchable mirror of microwaves and opens a good perspective for its applications in photonic quantum information processing and other fields.
305 citations
TL;DR: The authors' three-level artificial atom--a superconducting quantum circuit--coupled to a transmission line presents an analog of a natural atom in open space that is the most fundamental quantum amplifier whose gain is limited by a spontaneous emission mechanism.
Abstract: We report amplification of electromagnetic waves by a single artificial atom in open 1D space. Our three-level artificial atom-a superconducting quantum circuit-coupled to a transmission line presents an analog of a natural atom in open space. The system is the most fundamental quantum amplifier whose gain is limited by a spontaneous emission mechanism. The noise performance is determined by the quantum noise revealed in the spectrum of spontaneous emission, also characterized in our experiments.
120 citations
TL;DR: In this paper, the authors studied damping in polycrystalline Al nanomechanical resonators by measuring the temperature dependence of their resonance frequency and quality factor over a temperature range of 0.1-4 K. They concluded that the dynamics of the two-level systems is dominated by their interaction with one-dimensional phonon modes of the resonators.
Abstract: We have studied damping in polycrystalline Al nanomechanical resonators by measuring the temperature dependence of their resonance frequency and quality factor over a temperature range of 0.1-4 K. Two regimes are clearly distinguished with a crossover temperature of 1 K. Below 1 K we observe a logarithmic temperature dependence of the frequency and linear dependence of damping that cannot be explained by the existing standard models. We attribute these phenomena to the effect of the two-level systems characterized by the unexpectedly long (at least two orders of magnitude longer) relaxation times and discuss possible microscopic models for such systems. We conclude that the dynamics of the two-level systems is dominated by their interaction with one-dimensional phonon modes of the resonators.
48 citations
Book•
19 Nov 2010
TL;DR: In this paper, the authors present a detailed account of the transition of a Qubit from a single-person to a two-person QUBIT with the help of a femto-expander.
Abstract: TITLE CONDITIONAL GATE OPERATION IN SUPERCONDUCTING CHARGE QUBITS COUPLING AND DEPHASING IN JOSEPHSON CHARGE-PHASE QUBIT WITH RADIO-FREQUENCY READOUT THE JOSEPHSON BIFFURCATION FOR QUANTUM MEASUREMENTS CURRENT-CONTROLLED COUPLING OF SUPERCONDUCTING CHARGE QUBIT DIRECT MEASURES OF TUNABLE JOSEPHSON PLASMA RESONANCE IN THE L-SET TIME DOMAIN ANALYSIS OF DYNAMICAL SWITCHING IN A JOSEPHSON JUNCTION COOPER PAIR TRANSISTOR IN A TUNABLE ENVIRONMENT PHASE SLIP PHENOMENA IN ULTRA-THIN SUPERCONDUCTING WIRES DYNAMICS OF A QUBIT COUPLED TO A HARMONIC OSCILLATOR JOSEPHSON JUNCTION MATERIALS RESEARCH USING PHASE QUBITS ENERGY LEVEL SPECTROSCOPY OF A BOUND VORTEX-ANTIVORTEX PAIR ADIABATIC QUANTUM COMPUTATION WITH FLUX QUBITS ANOMALOUS THERMAL ESCAPE IN JOSEPHSON SYSTEMS PERTURBATED BY MICROWAVES REALIZATION AND CHARACTERIZATION OF A SQUID FLUX QUBIT WITH A DIRECT READOUT SCHEME A CRITIQUE OF THE TWO LEVEL APROXIMATION JOSEPHSON JUNCTION QUBITS WITH SYMMETRIZED COUPLINGS TO A RESONANT LC BUS SPATIAL BOSE EINSTEIN CONDENSATION IN JOSEPHSON JUNCTION ARRAYS COOPER PAIR SHUTTLE: A JOSEPHSON QUANTUM KICKED ROTATOR SIZE DEPENDENCE OF THE SUPERCONDUCTOR INSULATOR TRANSITION IN JOSEPHSON JUNCTION ARRAYS MONTE CARLO METHOD FOR A SUPERCONDUCTING COOPER-PAIR-BOX CHARGE QUBIT MEASURED BY A SINGLE-ELECTRON TRANSISTOR ON THE CONVERSION OF ULTRACOLD FERMIONICATOMS TO BOSONIC MOLECULES VIA FESHBACH RESONANCES REVEALING ANISOTROPY IN A PAUL TRAP THROUGH BERRY PHASE DISTILLING ANGULAR MOMENTUM SCHRODINGER CATS IN TRAPPED IONS LINEAR-RESPONSE CONDUCTANCE OF THE NORMAL CONDUCTING SINGLE-ELECTRON-PUMP TRASMISSION EIGENVALUES' STATISTICS FOR A QUANTUM POINT CONTACT SQUID RINGS AND ELECTROMAGNETIC FIELDS ENTANGLEMENTS BETWEEN ELECTROMAGNETICFIELD MODES VIA A MESOSCOPIC SQUID RING PHOTON-INDUCED ENTANGLEMENT OF DISTANT MESOSCOPIC SQUID RINGS TIME EVOLUTION OF TWO DISTANT SQUID RINGS IRRIDATED WITH ENTANGLED ELECTROMAGNETIC FIELD PHASE DIAGRAM OF DISSIPATIVE TWO-DIMENSIONAL JOSEPHSON JUNCTION ARRAYS PERSISTENT CURRENTS IN A SUOERCONDUCTOR/NORMAL LOOP JOSEPHSON JUNCTION LADDERS: A REALIZATION OF TOPOLOGICAL ORDER SINGLE-ELECTRON CHARGE QUBIT IN A DOUBLE QUANTUM DOT QUANTUM DOTS FOR SINGLE PHOTON AND PHOTON PAIR TECHNOLOGY SEMICONDUCTOR FEW-ELECTRON QUANTUM DOTS AS SPIN-QUBITS SPIN AMPLIFIER FOR SINGLE SPIN MEASUREMENT ENTANGLEMENT IN QUANTUM-CRITICAL SPIN DESIGNS CONTROL OF NUCLEAR SPINS BY QUANTUM HALL EDGE CHANNELS CLONING OF SINGLE PHOTON BY HIGH GAIN AMPLIFIER
26 citations
TL;DR: In this article, a doubly clamped single-electron transistor (SET) with a bottom gate with a larger capacitance to the SET island is placed underneath to increase the SET coupling to mechanical motion.
Abstract: We have suspended an Al based single-electron transistor (SET) whose island can resonate freely between the source and drain leads forming the clamps. In addition to the regular side gate, a bottom gate with a larger capacitance to the SET island is placed underneath to increase the SET coupling to mechanical motion. The device can be considered as a doubly clamped Al beam that can transduce mechanical vibrations into variations in the SET current. Our simulations based on the orthodox model, with the SET parameters estimated from the experiment, reproduce the observed transport characteristics in detail.
15 citations
13 Jun 2010
TL;DR: In this paper, a quantum current standard based on the hybrid superconductor-insulator-normal metal insulator-superconductor (SINIS) structure was developed for turnstile operation.
Abstract: We develop a quantum current standard based on the hybrid superconductor-insulator-normal-metal-insulator-superconductor (SINIS) structure in turnstile operation. We discuss the properties of the device and the relevant error sources. We also present a preliminary plan how to implement the device in a direct quantum metrological triangle experiment.
9 citations
TL;DR: In this paper, the authors used tunneling spectroscopy in Al and Nb based superconductor-insulator-superconductor (SIS) junctions to demonstrate the existence of metallic quasiparticle states at the interface of a superconducting electrode and an oxide layer.
Abstract: We use tunneling spectroscopy in Al and Nb based superconductor–insulator–superconductor (SIS) junctions to demonstrate the existence of metallic quasiparticle states at the interface of a superconducting electrode and an oxide layer, introducing a new method to directly evaluate the interface quasiparticle areal density of states. Current–voltage ( I – V ) characteristics typically observed in metal–insulator–superconductor (MIS) junctions are observed in the subgap voltage region. The turn-on voltage of the MIS-type leakage is found to be determined by the superconducting electrode with a smaller gap energy ( Δ ), and its magnitude depends on the nature of the interface. Our experiment suggests that the interface plays a key role in contributing to the subgap leakage influencing the performance of superconducting circuits.
5 citations
13 Jun 2010
TL;DR: In this article, a hybrid normal-metal-superconductor turnstile with one gate was proposed to achieve a metrological accuracy of 10−8, while maintaining the quantized current on the level of more than 10 pA.
Abstract: First I discuss various candidates of single-electron current pumps for quantum metrology. Then I focus on the hybrid normal-metal-superconductor turnstile in the form of a one-island single-electron transistor with one gate [1-3]. The device demonstrates robust current plateaus at multiple levels of ef at frequency f. I discuss the various error mechanisms, based on our experiments and theoretical considerations. Ultimately the quantization accuracy is expected to be limited by either two-electron tunneling or by Cooper-pair-electron co-tunneling [4]. We predict that it should be possible to achieve the metrological accuracy of 10−8, while maintaining the quantized current on the level of more than 10 pA, just by one turnstile with realistic parameters using aluminium as a superconductor. Recently we have managed to run ten turnstiles in parallel increasing the current level to above 100 pA [5]. Work on suppressing the harmful sub-gap leakage current is in progress with encouraging experimental results.
1 citations