Negative excess noise in quantum conductors

Lesovik, G. B.; Loosen, Roland

doi:10.1007/bf01316834

Cited by 29 publications

(23 citation statements)

References 14 publications

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“…This is not generally correct if the transmission coefficients are strongly energy dependent. As pointed out by Lesovik and Loosen [13], in certain situations (for instance, when the transmission coefficients sharply peak as functions of energy) the total non-equilibrium noise may be actually lower than the equilibrium noise at the same temperature.…”

Section: General Expressions For Noisementioning

confidence: 95%

Shot noise in mesoscopic conductors

2000

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Theoretical and experimental work concerned with dynamic fluctuations has developed into a very active and fascinating subfield of mesoscopic physics. We present a review of this development focusing on shot noise in small electric conductors. Shot noise is a consequence of the quantization of charge. It can be used to obtain information on a system which is not available through conductance measurements. In particular, shot noise experiments can determine the charge and statistics of the quasiparticles relevant for transport, and reveal information on the potential profile and internal energy scales of mesoscopic systems. Shot noise is generally more sensitive to the effects of electron-electron interactions than the average conductance. We present a discussion based on the conceptually transparent scattering approach and on the classical Langevin and BoltzmannLangevin methods; in addition a discussion of results which cannot be obtained by these methods is provided. We conclude the review by pointing out a number of unsolved problems and an outlook on the likely future development of the field.

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Section: General Expressions For Noisementioning

confidence: 95%

Shot noise in mesoscopic conductors

2000

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“…For noninteracting electrons in quantum conductors, such examples have been provided by Lesovik and Loosen. 21 We can also mention more familiar examples from semiconductor device literature. For instance, in Schottky-barrier diodes or p-n junctions, in the range of the exponential I-V characteristics, the current-noise power is given by S I ϭ2k B TG, which is a half of the thermal noise value given by the Nyquist relationship.…”

Section: A Fixed-bias Conditions: ␦Vä0mentioning

confidence: 99%

“…For noninteracting systems, such examples have been given by Lesovik and Loosen. 21 To support our statement we present a theory of current and voltage fluctuations in a ballistic two-terminal conductor in a self-consistent field ͑Fig. 1͒.…”

Section: ͑3͒mentioning

confidence: 99%

Self-consistent theory of current and voltage noise in multimode ballistic conductors

Bulashenko

Rubı́

2002

Phys. Rev. B

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Electron transport in a self-consistent potential along a ballistic two-terminal conductor has been investigated. We have derived general formulas which describe the nonlinear current-voltage characteristics, differential conductance, and low-frequency current and voltage noise assuming an arbitrary distribution function and correlation properties of injected electrons. The analytical results have been obtained for a wide range of biases: from equilibrium to high values beyond the linear-response regime. The particular case of a threedimensional Fermi-Dirac injection has been analyzed. We show that the Coulomb correlations are manifested in the negative excess voltage noise, i.e., the voltage fluctuations under high-field transport conditions can be less than in equilibrium.

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“…[6], and in Refs. [7] for quantum wires and carbon nanotubes connected to metallic leads, where it was shown that, while the presence of the metallic leads obscures it in the zero-frequency noise, the charge fractionalization is still present and can be extracted from the noise at high frequencies.Nevertheless, recent experiments [8] have got access to the non-symmetrized noise [9], and thus to the emission and the absorption components of the noise spectrum given by the noise at positive/negative frequencies. What is usually measured is the excess non-symmetrized noise, defined as the difference between the noise at finite voltage and at zero voltage, thus allowing to get rid of some undesirable effects.…”

mentioning

confidence: 99%

“…Nevertheless, recent experiments [8] have got access to the non-symmetrized noise [9], and thus to the emission and the absorption components of the noise spectrum given by the noise at positive/negative frequencies. What is usually measured is the excess non-symmetrized noise, defined as the difference between the noise at finite voltage and at zero voltage, thus allowing to get rid of some undesirable effects.…”

mentioning

confidence: 99%

Asymmetry of the excess finite-frequency noise

Safi¹,

Macucci²,

Basso³

2009

AIP Conference Proceedings

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We consider finite frequency noise in a mesoscopic system with arbitrary interactions, connected to many terminals kept at finite electrochemical potentials. We show that the excess noise, obtained by subtracting the noise at zero voltage from that at finite voltage, can be asymmetric with respect to positive/negative frequencies if the system is non-linear. This explains a recent experimental observation in Josephson junctions as well as strong asymmetry obtained in typical non-linear and strongly correlated systems described by the Luttinger liquid (LL): edge states in the fractional quantum Hall effect, quantum wires and carbon nanotubes. Another important problem where the LL model applies is that of a coherent conductor embedded in an ohmic environment. PACS numbers:The finite frequency (FF) current fluctuations have attracted a lot of interest in the mesoscopic community [1,2]. It has been possible to measure them in the quantum regime, i. e. at frequencies higher than temperature. Beyond the average current, they offer a powerful tool to reveal the charge and statistics of the charge carriers of a system when considered at zero-frequency. Nevertheless, they contain more rich informations at FF, such as on elementary excitations, typical energy scales, and especially on interactions, with the possibility to check the underlying model or access the correlation strength etc...It has been often stated in theoretical studies that one needs to symmetrize the current correlators, as they don't commute at different times, which leads to a FF symmetrized noise, symmetric with respect to positive/negative frequencies. Nevertheless, this has been often explored by the scattering approach at low frequencies compared to characteristic energy scales [2]. Few theoretical works went beyond this framework [3]. It has also been studied in systems where interactions intervene at any frequency scale in the FF noise such as chiral edge states in the Fractional Quantum Hall effect (FQHE), quantum wires and carbon nanotubes, described by the Luttinger liquid (LL) model, which leads to exotic phenomena such as charge fractionalization [5], spin-charge separation, and fractional statistics. It has been shown that LL is suited as well to describe a coherent conductor embedded into an ohmic environment [4]. The symmetrized FF noise has been studied in the FQHE in Ref. [6], and in Refs. [7] for quantum wires and carbon nanotubes connected to metallic leads, where it was shown that, while the presence of the metallic leads obscures it in the zero-frequency noise, the charge fractionalization is still present and can be extracted from the noise at high frequencies.Nevertheless, recent experiments [8] have got access to the non-symmetrized noise [9], and thus to the emission and the absorption components of the noise spectrum given by the noise at positive/negative frequencies. What is usually measured is the excess non-symmetrized noise, defined as the difference between the noise at finite voltage and at zero voltage, thus allowing t...

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Negative excess noise in quantum conductors

Cited by 29 publications

References 14 publications

Shot noise in mesoscopic conductors

Shot noise in mesoscopic conductors

Self-consistent theory of current and voltage noise in multimode ballistic conductors

Asymmetry of the excess finite-frequency noise

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