University of Basel  > Condensed Matter Theory

Massoud Borhani 

Address:  Office 4.6 
Department of Physics and Astronomy 
University of Basel 
Klingelbergstrasse 82 
CH-4056 Basel, Switzerland
phone (office):  +41 61 267 3744 
fax:  +41 61 267 1349


Research Interest

Solid State Based Quantum Information Processing
1- Spin Manipulation and Decoherence in Quantum Dots
2- Physical Realization of the One-way and Holonomic Quantum Computation

Many Body Physics
1- Fermi and Non-Fermi Liquid Theory
2- Nonanalytic Corrections to the Fermi Liquid Behavior

Physics of Extra Dimensions
1- Classical Brane Worlds in Cosmology
2- Brans-Dicke Theories in Dimensions Higher Than 4
3- Field Dependence of the Gravitational Constant in Einstein's Equations

Fundamental Physics
1- Alternative Interpretations of Quantum Mechanics (esp. Bohmian Mechanics)
2- Measurement Problem in Quantum Mechanics
3- Classical Limit


BSc. in Physics, Sharif University, Tehran, Iran (2002)
MSc. in Physics, University of Basel, Switzerland (2004)
PhD. in Physics, University of Basel, Switzerland (2008)

Theory of Spin Qubits in Nanostructures
Björn Trauzettel, Massoud Borhani, Mircea Trif, Daniel Loss
JPSJ Special Topics: Advances in Spintronics.
J. Phys. Soc. Jpn. 77, 031012 (2008) ( Arxiv:0707.4622 )

Electric Dipole Induced Spin Resonance in Quantum Dots
Vitaly N. Golovach, Massoud Borhani, Daniel Loss
Phys. Rev. B 74, 165319 (2006) (cond-mat/0601674 )

An alternating electric field, applied to a ``spin 1/2'' quantum dot, couples to the electron spin via the spin-orbit interaction. We analyze different types of spin-orbit couplings known in the literature and find that an electric dipole spin resonance (EDSR) scheme for spin manipulation can be realized with the up-to-date experimental setups. In particular, for the Rashba and Dresselhaus spin-orbit couplings, a fully transverse effective magnetic field arises in the presence of a Zeeman splitting in the lowest order of spin-orbit interaction. Spin manipulation and measurement of the spin decoherence time T_2 are straightforward in lateral GaAs quantum dots through the use of EDSR.

Spin Decay in a Quantum Dot Coupled to a Quantum Point Contact
Massoud Borhani, Vitaly N. Golovach, Daniel Loss
Phys. Rev. B 73, 155311 (2006) (cond-mat/0510758 )

We consider a mechanism of spin decay for an electron spin in a quantum dot due to coupling to a nearby quantum point contact (QPC) with and without an applied bias voltage. The coupling of spin to charge is induced by the spin-orbit interaction in the presence of a magnetic field. We perform a microscopic calculation of the effective Hamiltonian coupling constants to obtain the QPC-induced spin relaxation and decoherence rates in a realistic system. This rate is shown to be proportional to the shot noise of the QPC in the regime of large bias voltage and scales as "a-6" where "a" is the distance between the quantum dot and the QPC. We find that, for some specific orientations of the setup with respect to the crystallographic axes, the QPC-induced spin relaxation and decoherence rates vanish, while the charge sensitivity of the QPC is not changed. This result can be used in experiments to minimize QPC-induced spin decay in read-out schemes.

Cluster States From Heisenberg Interaction
Massoud Borhani, Daniel Loss
Phys. Rev. A 71, 034308 (2005) (quant-ph/0410145)

We show that a special type of entangled states, cluster states, can be created with Heisenberg interactions and local rotations in 2d steps where d is the dimension of the lattice. We find that, by tuning the coupling strengths, anisotropic exchange interactions can also be employed to create cluster states. Finally, we propose electron spins in quantum dots as a possible realization of a one-way quantum computer based on cluster states.

Spherically Symmetric Thick Branes In Vacuum
Massoud Borhani, Reza Mansouri, Samad Khakshournia
Int. J. Mod. Phys. A 19, 4687 (2004) (hep-th/0301228 )

We consider a spherical thick 3-brane immersed in a five-dimensional bulk spacetime. We demonstrate how the thick brane equation of motion expanded in powers of the thickness of the brane can be obtained from the expected junction conditions on the boundaries of thick brane with the two embedding spacetimes. It is shown that the finite thickness leads to a faster collapse of the spherical shell.

PASPS V, August 2008, Foz Do Iguacu (Brazil).

Swiss Wokshop on Basic Research in Nanoscience, June 2008, Davos (Switzerland).

Frontiers in Nanoscale Science and Technology, January 2008, Basel (Switzerland).

Quantum Transport and Dynamics in Nanostructures, August 2007, Windsor, London (England).

DPG Meeting, March 2007, Regensburg, Bavaria (Germany).

International Conference on Nanoscience and Technology (ICN+T 2006), July & August 2006, Basel (Switzerland).

Spin and Charge Effects at the Nanoscale, June 2006, Pisa (Italy).

DPG Meeting, March 2006, Dresden (Germany).

International Symposium on Mesoscopic Superconductivity and Spintronics, February 2006, NTT Lab, Atsugi (Japan).

Swiss Physical Society Meeting, Februaray 2006, EPFL, Lausanne (Switzerland).

NCCR Meeting, September 2005, Gwatt (Switzerland).

Quantum Coherence, August 2005, Monte Verita, Ascona (Switzerland).

DPG Meeting, March 2005, Berlin (Germany).

Solid State Based Quantum Information Processing, September 2004, Herrsching (Germany).

Quantum Information Meeting, March 2004, Flums (Switzerland).

Summer School on String Theory, Astroparticle Physics and Cosmology, June & July 2002, Trieste (Italy).