Related papers: Finite-frequency noise in a quantum dot with norma…
We consider a three-terminal system consisting of a quantum dot strongly coupled to two superconducting reservoirs in the infinite gap limit and weakly coupled to a normal metal. Using a real-time diagrammatic approach, we calculate the…
We analyze the problem of directed quantum transport induced by external exponentially correlated telegraphic noise. In addition to quantum nature of the heat bath, nonlinearity of the periodic system potential brings in quantum…
We report a direct measurement of the low-frequency noise spectrum in a superconducting flux qubit. Our method uses the noise sensitivity of a free-induction Ramsey interference experiment, comprising free evolution in the presence of noise…
Decoherence induced by the laser frequency noise is one of the most important obstacles in the quantum information processing. In order to suppress this decoherence, the noise power spectral density needs to be accurately characterized. In…
We study Cooper pair transport through a quantum point contact between a superconductor and a quantum Hall edge state at integer and fractional filling factors. We calculate the tunnelling current and its finite-frequency noise to the…
Finite frequency current noise is studied theoretically for a 1D electron system in presence of a scatterer. In contrast to zero frequency shot noise, finite frequency noise shows spatial oscillations at high frequencies with wavelength…
Equilibrium transport properties of a single-level quantum dot tunnel-coupled to ferromagnetic leads and exchange-coupled to a side nonmagnetic reservoir are analyzed theoretically in the Kondo regime. The equilibrium spectral functions and…
The quantum indeterminacy caused by non-commutativity of observables at different times sets a lower bound on the voltage noise power spectrum in any conducting material. This bound is calculated explicitly in the case of semiconductors…
We study the in-gap states of the quantum dot hybridized to a conducting and superconducting electrode. The usual proximity effect suppresses electronic states over the entire subgap regime $|\omega| < \Delta$, where $\Delta$ denotes the…
We study the quantum charge noise and measurement properties of the double Cooper pair resonance point in a superconducting single-electron transistor (SSET) coupled to a Josephson charge qubit. Using a density matrix approach for the…
We propose and analyze continuous measurements of atom number and atomic currents using dispersive probing in an optical cavity. For an atom-number measurement in a closed system, we relate both the detection noise and the heating rate due…
We study the interacting quantum dot coupled to the normal and superconducting leads by means of a continuous-time quantum Monte Carlo method in the Keldysh-Nambu formalism. Deducing the steady current through the quantum dot under a finite…
Quantum harmonic oscillators are central to many modern quantum technologies. We introduce a method to determine the frequency noise spectrum of oscillator modes through coupling them to a qubit with continuously driven…
In the literature, the study of electron transport in quantum devices is mainly devoted to DC properties. The fluctuations of the electrical current around these DC values, the so-called quantum noise, are much less analyzed. The…
We show that, for a quantum point contact between two superconductors of different gap magnitudes, Andreev bound states do not exist for certain phase differences and gap ratios. Continuum states may dominate the transport, and the…
We study coherent oscillations in double quantum dots tunnel-coupled to metallic leads by means of full counting statistics of electron transport. If two such systems are coupled by Coulomb interaction, there are in total six (instead of…
In quantum information processing, knowledge of the noise in the system is crucial for high-precision manipulation and tomography of coherent quantum operations. Existing strategies for identifying this noise require the use of additional…
We study transport properties for a quantum dot coupled to normal leads with a pseudogap density of states at zero temperature, using the second-order perturbation theory based on the Keldysh formalism. We clarify that the hybridization…
Periodic driving of quantum dots is analyzed as a basis for developing dynamic switching devices. We study transport through periodically modulated energy levels which are coupled to leads via tunneling coefficients. Utilizing Floquet…
We study excess noise in a quantum conductor in the presence of constant voltage and alternating external field. Due to a two particle interference effect caused by Fermi correlations the noise is sensitive to the phase of the time…