Fernando Domínguez

Publications (4)0 Total impact

• Source

  Available from: Gloria Platero

  Article: Dynamical detection of Majorana fermions in current-biased nanowires

  Fernando Domínguez, Fabian Hassler, Gloria Platero
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  ABSTRACT: We analyze the current-biased Shapiro experiment in a Josephson junction formed by two one-dimensional nanowires featuring Majorana fermions. Ideally, these junctions are predicted to have an unconventional $4\pi$-periodic Josephson effect and thus only Shapiro steps at even multiples of the driving frequency. Taking additionally into account overlap between the Majorana fermions, due to the finite length of the wire, renders the Josephson junction conventional for any dc-experiments. We show that probing the current-phase relation in a current biased setup dynamically decouples the Majorana fermions. We find that besides the even integer Shapiro steps there are additional steps at odd and fractional values. However, different from the voltage biased case, the even steps dominate for a wide range of parameters even in the case of multiple modes thus giving a clear experimental signature of the presence of Majorana fermions.
  02/2012;
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  Available from: Gloria Platero

  Article: Phonon-mediated decoherence in triple quantum dot interferometers

  Fernando Domínguez, Sigmund Kohler, Gloria Platero
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  ABSTRACT: We investigate decoherence in a triple quantum dot in ring configuration in which one dot is coupled to a damped phonon mode, while the other two dots are connected to source and drain, respectively. In the absence of decoherence, single electron transport may get blocked by an electron falling into a superposition decoupled from the drain and known as dark state. Phonon-mediated decoherence affects this superposition and leads to a finite current. We study the current and its shot noise numerically within a master equation approach for the electrons and the dissipative phonon mode. A polaron transformation allows us to obtain a reduced equation for only the dot electrons which provides analytical results in agreement with numerical ones.
  03/2011;
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  Available from: Gloria Platero

  Article: Hyperfine mediated triplet-singlet transition probability in a double-quantum-dot system: Analogy with the double-slit experiment

  Fernando Domínguez, Gloria Platero
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  ABSTRACT: We apply an elementary measurement scheme to calculate the electronic triplet-singlet transition mediated by hyperfine interaction in a double-quantum dot. We show how the local character of the hyperfine interaction and the nuclear back-action process (flip-flop) are crucial to cancel destructive interferences of the triplet-singlet transition probability. It is precisely this cancellation that differentiates the hyperfine interaction from an anisotropic magnetic field which mixes the triplet and the singlet eigenstates.
  Phys. Rev. B. 10/2009; 80(20).
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  Available from: Gloria Platero

  Article: Electron bunching in triple quantum dot interferometers

  Fernando Domínguez, Gloria Platero, Sigmund Kohler
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  ABSTRACT: We study electron transport through a triple quantum dot in ring or interferometer configuration. In particular, we analyze the influence of a gate voltage that detunes one of the dots, such that it becomes off-resonant. In this regime, interference effects fade away, i.e., the current becomes independent of a penetrating flux. Despite the absence of interference effects, the off-resonant dot causes intriguing noise properties which we characterize by the full-counting statistics of the transported electrons. It turns out that the detuning causes strong electron bunching. Analytical results for limiting cases support this picture. A possible application is the construction of current sources with widely tunable noise properties.
  Chemical Physics.