Gate-tunable zero-frequency current cross-correlations of the quartet mode in a voltage-biased three-terminal Josephson junction

Abstract

A three-terminal Josephson junction biased at opposite voltages can sustain a phase-sensitive dc-current carrying three-body static phase coherence, known as the "quartet current". We calculate the zero-frequency current noise cross-correlations and answer the question of whether this current is noisy (like a normal current in response to a voltage drop) or noiseless (like an equilibrium supercurrent in response to a phase drop). A quantum dot with a level at energy ${\epsilon }_0$ is connected to three superconductors $S_a$, $S_b$ and $S_c$ with gap $\Delta$, biased at $V_a=V$, $V_b=-V$ and $V_c=0$, and with intermediate contact transparencies. At zero temperature, nonlocal quartets (in the sense of four-fermion correlations) are noiseless at subgap voltage in the nonresonant dot regime ${\epsilon }_0/\Delta \gg 1$, which is demonstrated with a semi-analytical perturbative expansion of the cross-correlations. Noise reveals the absence of granularity of the superflow splitting from $S_c$ towards $(S_a,S_b)$ in the nonresonant dot regime, in spite of finite voltage. In the resonant dot regime ${\epsilon }_0/\Delta <1$, cross-correlations measured in the $(V_a,V_b)$ plane should reveal an "anomaly" in the vicinity of the quartet line $V_a+V_b=0$, related to an additional contribution to the noise, manifesting the phase sensitivity of cross-correlations under the appearance of a three-body phase variable. Phase-dependent effective Fano factors $F_{\phi }$ are introduced, defined as the ratio between the amplitudes of phase modulations of the noise and the currents. At low bias, the Fano factors $F_{\phi }$ are of order unity in the resonant dot regime ${\epsilon }_0/\Delta <1$, and they are vanishingly small in the nonresonant dot regime ${\epsilon }_0/\Delta \gg 1$.

11 pages, 7 figures, improvements in presentation

References in corpus (12)

• Single fermion manipulation via superconducting phase differences in multiterminal Josephson junctions
• Current-current correlations in hybrid superconducting and normal metal multiterminal structures
• Production of non-local quartets and phase-sensitive entanglement in a superconducting beam splitter
• Circuit theory of crossed Andreev reflection
• Voltage-induced Shapiro steps in a superconducting multi-terminal structure
• Full counting statistics of crossed Andreev reflection
• Closing the proximity gap in a metallic Josephson junction between three superconductors
• Positive current cross-correlations in a highly transparent normal-superconducting beam splitter due to synchronized Andreev and inverse Andreev reflections
• Multiple Andreev reflections in hybrid multiterminal junctions
• Elementary Charge Transfer Processes in a Superconductor-Ferromagnet Entangler
• Cross-correlations of coherent multiple Andreev reflections
• Phase-dependent noise correlations in normal-superconducting structures

Cited by in corpus (15)

• Nonlocal Josephson effect in Andreev molecules
• Non-local Supercurrent of Quartets in a Three-Terminal Josephson Junction
• Simple Floquet-Wannier-Stark-Andreev viewpoint and emergence of low-energy scales in a voltage-biased three-terminal Josephson junction
• Engineering the Floquet spectrum of superconducting multiterminal quantum dots
• Andreev processes in mesoscopic multi-terminal graphene Josephson junctions
• Inversion in a four-terminal superconducting device on the quartet line: I. Two-dimensional metal and the quartet beam splitter
• Inversion in a four terminal superconducting device on the quartet line: II. Quantum dot and Floquet theory
• A quantum interferometer for quartets in superconducting three-terminal Josephson junctions
• Ultralong-distance quantum correlations in three-terminal Josephson junctions
• Theory of non-equilibrium noise in general multi-terminal superconducting hydrid devices: application to multiple Cooper pair resonances
• Cross-correlations in a quantum dot Cooper pair splitter with ferromagnetic leads
• Quartet Tomography in Multiterminal Josephson Junctions
• Ballistic Andreev interferometers
• Multiterminal ballistic Josephson junctions coupled to normal leads
• Revisiting the adiabatic limit in ballistic multiterminal Josephson junctions