Pratyush Pandey

Automated error correction in IBM quantum computer and explicit generalization

Construction of a fault-tolerant quantum computer remains a challenging problem due to unavoidable noise and fragile quantum states. However, this goal can be achieved by introducing quantum error-correcting codes. Here, we experimentally realize an automated error correction code and demonstrate the nondestructive discrimination of GHZ states in IBM 5-qubit quantum computer. After performing quantum state tomography, we obtain the experimental results with a high fidelity. Finally, we generalize the investigated code for maximally entangled n-qudit case, which could both detect and automatically correct any arbitrary phase-change error, or any phase-flip error, or any bit-flip error, or combined error of all types of error.

Steep slope transistors: Tunnel FETs and beyond

Low voltage transistors are being developed to achieve steep, less than 60 mV/decade, subthreshold swings at room temperature. This paper outlines progress, technical challenges, and applications for these devices.

Electric-double-layer doping of WSe2 field-effect transistors using polyethylene-oxide cesium perchlorate

Electric double layers (EDLs) formed between polyethylene oxide cesium perchlorate and multilayer WSe2 field-effect transistors (FETs) are explored as a means for contact and access region doping. In this application, the electric double layer is formed using a top field plate or a side gate and then locked into place by cooling of the device below the glass transition temperature of the polymer. A dual work-function Ti/Pd contact is used to form the Schottky contacts with Ti as the n-contact and Pd as the p-contact and these are evaporated in a single evaporation. Using the EDL doping technique, sheet carrier density and current density are as high as (4.9 ± 1.9) × 1013 cm−2 and 58 μA/μm for n-doping and (3.5 ± 1.9) × 1013 cm−2 and 50 μA/μm for p-doping for the highest channel conductivities. The weak temperature dependence of the transfer characteristics at high doping levels reveals that the current in the Schottky contacts is dominated by tunneling with a contact resistance of 1 kΩ μm for the p-branch...

Partial switching of ferroelectrics for synaptic weight storage

Gokmen and Vlasov proposed that the training of deep neural networks would be dramatically accelerated by the realization of resistive processing units that can store analog weights to minimize data movement during training [1]. Here we measure and evaluate the partial switching of the ferroelectric (FE) PbZrTiO3 (PZT) and, for the first time, Hf0 8Zr0 2O2, (HZO), formed by atomic layer deposition, for use as a nonvolatile analog memory element. The spontaneous polarization P of a FE can be switched by applying a voltage that exceeds the coercive voltage for switching of the FE. This polarization, when fully switched, can have a value of +P or −P (C/cm2), depending on the polarity of the applied voltage. Ferroelectric memory is typically operated in fully switched +P or −P polarizations, however with short (< 10 μs) pulsed voltages, the FE can be partially switched, i.e. only a fraction of the domains are switched during the pulse duration as shown by Tokumitsu in PZT [2] and indicated in Fig. 1.