Measurement Back-Action in Quantum Point-Contact Charge Sensing

Charge sensing with quantum point-contacts (QPCs) is a technique widely used in semiconductor quantum-dot research. Understanding the physics of this measurement process, as well as finding ways of suppressing unwanted measurement back-action, are therefore both desirable. In this article, we present experimental studies targeting these two goals. Firstly, we measure the effect of a QPC on electron tunneling between two InAs quantum dots, and show that a model based on the QPC’s shot-noise can account for it. Secondly, we discuss the possibility of lowering the measurement current (and thus the back-action) used for charge sensing by correlating the signals of two independent measurement channels. The performance of this method is tested in a typical experimental setup.

[1]  W. Wegscheider,et al.  Phonon-mediated versus coulombic backaction in quantum dot circuits. , 2009, Physical review letters.

[2]  D. DiVincenzo,et al.  Quantum computation with quantum dots , 1997, cond-mat/9701055.

[3]  Kouwenhoven,et al.  Double quantum dots as detectors of high-frequency quantum noise in mesoscopic conductors , 1999, Physical review letters.

[4]  Jacob M. Taylor,et al.  Coherent Manipulation of Coupled Electron Spins in Semiconductor Quantum Dots , 2005, Science.

[5]  R. N. Schouten,et al.  Cryogenic amplifier for fast real-time detection of single-electron tunneling , 2007, 0708.0461.

[6]  A. Gossard,et al.  Rapid single-shot measurement of a singlet-triplet qubit. , 2009, Physical review letters.

[7]  A. Jordan,et al.  Continuous quantum measurement with independent detector cross correlations. , 2005, Physical review letters.

[8]  Esteve,et al.  Effect of the electromagnetic environment on the Coulomb blockade in ultrasmall tunnel junctions. , 1990, Physical review letters.

[9]  T. Ihn,et al.  Noise-induced spectral shift measured in a double quantum dot , 2009, 0904.3656.

[10]  T. Ihn,et al.  Time-resolved charge detection with cross-correlation techniques , 2008, 0810.2406.

[11]  Persistent Rabi oscillations probed via low-frequency noise correlation , 2010, 1004.0220.

[12]  On the detection of finite-frequency current fluctuations , 1997, 0803.0020.

[13]  S. Machlup,et al.  Noise in Semiconductors: Spectrum of a Two‐Parameter Random Signal , 1954 .

[14]  Telegraph noise in coupled quantum dot circuits induced by a quantum point contact. , 2008, Physical review letters.

[15]  J. Bird.  Electron transport in quantum dots , 2003 .

[16]  V. Umansky,et al.  Dephasing in electron interference by a ‘which-path’ detector , 1998, Nature.

[17]  A. Gossard,et al.  Frequency-selective single-photon detection using a double quantum dot. , 2007, Physical review letters.

[18]  S. Tarucha,et al.  Current Rectification by Pauli Exclusion in a Weakly Coupled Double Quantum Dot System , 2002, Science.

[19]  C. Buizert,et al.  Driven coherent oscillations of a single electron spin in a quantum dot , 2006, Nature.

[20]  Gordey B. Lesovik,et al.  Excess quantum noise in 2d ballistic point contacts , 1989 .

[21]  S. Tarucha,et al.  Multiple Photon Assisted Tunneling between Two Coupled Quantum Dots , 1997 .

[22]  W Wegscheider,et al.  Double-dot quantum ratchet driven by an independently biased quantum point contact. , 2006, Physical review letters.

[23]  L. Vandersypen,et al.  Single-shot read-out of an individual electron spin in a quantum dot , 2004, Nature.

[24]  Büttiker,et al.  Quantized transmission of a saddle-point constriction. , 1990, Physical review. B, Condensed matter.

[25]  Ritchie,et al.  Measurements of Coulomb blockade with a noninvasive voltage probe. , 1993, Physical Review Letters.

[26]  L. Vandersypen,et al.  Real-time detection of single-electron tunneling using a quantum point contact , 2004, cond-mat/0407121.

[27]  U. Gasser,et al.  Statistical electron excitation in a double quantum dot induced by two independent quantum point contacts , 2008, 0808.2905.

[28]  K. Ensslin,et al.  Correlated counting of single electrons in a nanowire double quantum dot , 2008, 0812.2008.

[29]  Photon-assisted transport in semiconductor nanostructures , 2003, cond-mat/0311001.

[30]  A. Gossard,et al.  Fast single-charge sensing with a rf quantum point contact , 2007, 0707.2946.