



@article {2579,
	title = {Studying viral populations with tools from quantum spin chains},
	year = {2020},
	month = {3/24/2020},
	abstract = {<p>We study Eigen\&$\#$39;s model of quasi-species, characterized by sequences that replicate with a specified fitness and mutate independently at single sites. The evolution of the population vector in time is then closely related to that of quantum spins in imaginary time. We employ multiple perspectives and tools from interacting quantum systems to examine growth and collapse of realistic viral populations, specifically certain HIV proteins. All approaches used, including the simplest perturbation theory, give consistent results.</p>},
	url = {https://arxiv.org/abs/2003.10668},
	author = {Saumya Shivam and Christopher L. Baldwin and John Barton and Mehran Kardar and S. L. Sondhi}
}
@article {1527,
	title = {Flight of a heavy particle nonlinearly coupled to a quantum bath},
	journal = {Physical Review B},
	volume = {93},
	year = {2016},
	month = {2016/01/28},
	pages = {014309},
	abstract = {  Fluctuation and dissipation are by-products of coupling to the {\textquoteleft}environment.{\textquoteright}
The Caldeira-Leggett model, a successful paradigm of quantum Brownian motion,
views the environment as a collection of harmonic oscillators linearly coupled
to the system. However, symmetry considerations may forbid a linear coupling,
e.g. for a neutral particle in quantum electrodynamics. We argue that nonlinear
couplings can lead to a fundamentally different behavior. Specifically, we
consider a heavy particle quadratically coupled to quantum fluctuations of the
bath. In one dimension the particle undergoes anomalous diffusion, unfolding as
a power-law distribution in space, reminiscent of L\'{e}vy flights. We suggest
condensed matter analogs where similar effects may arise.
},
	doi = {10.1103/PhysRevB.93.014309},
	url = {http://arxiv.org/abs/1508.00582},
	author = {Mohammad F. Maghrebi and Matthias Kr{\"u}ger and Mehran Kardar}
}
@article {1530,
	title = {Nonequilibrium quantum fluctuations of a dispersive medium: Spontaneous  emission, photon statistics, entropy generation, and stochastic motion
},
	journal = {Physical Review A},
	volume = {90},
	year = {2014},
	month = {2014/7/16},
	abstract = {  We study the implications of quantum fluctuations of a dispersive medium,
under steady rotation, either in or out of thermal equilibrium with its
environment. A rotating object exhibits a quantum instability by dissipating
its mechanical motion via spontaneous emission of photons, as well as internal
heat generation. Universal relations are derived for the radiated energy and
angular momentum as trace formulas involving the object{\textquoteright}s scattering matrix. We
also compute the quantum noise by deriving the full statistics of the radiated
photons out of thermal and/or dynamic equilibrium. The (entanglement) entropy
generation is quantified, and the total entropy is shown to be always
increasing. Furthermore, we derive a Fokker-Planck equation governing the
stochastic angular motion resulting from the fluctuating back-reaction
frictional torque. As a result, we find a quantum limit on the uncertainty of
the object{\textquoteright}s angular velocity in steady rotation. Finally, we show in some
detail that a rotating object drags nearby objects, making them spin parallel
to its axis of rotation. A scalar toy model is introduced in the first part to
simplify the technicalities and ease the conceptual complexities; a detailed
discussion of quantum electrodynamics is presented in the second part.
},
	doi = {10.1103/PhysRevA.90.012515},
	url = {http://arxiv.org/abs/1401.0701v1},
	author = {Mohammad F. Maghrebi and Robert L. Jaffe and Mehran Kardar}
}
@article {1522,
	title = {Quantum Cherenkov Radiation and Non-contact Friction},
	journal = {Physical Review A},
	volume = {88},
	year = {2013},
	month = {2013/10/21},
	abstract = {  We present a number of arguments to demonstrate that a quantum analog of
Cherenkov effect occurs when two dispersive objects are in relative motion.
Specifically we show that two semi-infinite plates experience friction beyond a
threshold velocity which, in their center-of-mass frame, is the phase speed of
light within their medium. The loss in mechanical energy is radiated away
through the plates before getting fully absorbed in the form of heat. By
deriving various correlation functions inside and outside the two plates, we
explicitly compute the radiation, and discuss its dependence on the reference
frame.
},
	doi = {10.1103/PhysRevA.88.042509},
	url = {http://arxiv.org/abs/1304.4909v2},
	author = {Mohammad F. Maghrebi and Ramin Golestanian and Mehran Kardar}
}
@article {1525,
	title = {A Scattering Approach to the Dynamical Casimir Effect},
	journal = {Physical Review D},
	volume = {87},
	year = {2013},
	month = {2013/1/7},
	abstract = {  We develop a unified scattering approach to dynamical Casimir problems which
can be applied to both accelerating boundaries, as well as dispersive objects
in relative motion. A general (trace) formula is derived for the radiation from
accelerating boundaries. Applications are provided for objects with different
shapes in various dimensions, and undergoing rotational or linear motion.
Within this framework, photon generation is discussed in the context of a
modulated optical mirror. For dispersive objects, we find general results
solely in terms of the scattering matrix. Specifically, we discuss the vacuum
friction on a rotating object, and the friction on an atom moving parallel to a
surface.
},
	doi = {10.1103/PhysRevD.87.025016},
	url = {http://arxiv.org/abs/1210.1842v2},
	author = {Mohammad F. Maghrebi and Ramin Golestanian and Mehran Kardar}
}
@article {1524,
	title = {Polymer-mediated entropic forces between scale-free objects},
	journal = {Physical Review E},
	volume = {86},
	year = {2012},
	month = {2012/12/3},
	abstract = {  The number of configurations of a polymer is reduced in the presence of a
barrier or an obstacle. The resulting loss of entropy adds a repulsive
component to other forces generated by interaction potentials. When the
obstructions are scale invariant shapes (such as cones, wedges, lines or
planes) the only relevant length scales are the polymer size R_0 and
characteristic separations, severely constraining the functional form of
entropic forces. Specifically, we consider a polymer (single strand or star)
attached to the tip of a cone, at a separation h from a surface (or another
cone). At close proximity, such that h<<R_0, separation is the only remaining
relevant scale and the entropic force must take the form F=AkT/h. The amplitude
A is universal, and can be related to exponents \eta governing the anomalous
scaling of polymer correlations in the presence of obstacles. We use
analytical, numerical and epsilon-expansion techniques to compute the exponent
\eta for a polymer attached to the tip of the cone (with or without an
additional plate or cone) for ideal and self-avoiding polymers. The entropic
force is of the order of 0.1 pN at 0.1 micron for a single polymer, and can be
increased for a star polymer.
},
	doi = {10.1103/PhysRevE.86.061801},
	url = {http://arxiv.org/abs/1208.5778v2},
	author = {Mohammad F. Maghrebi and Yacov Kantor and Mehran Kardar}
}
@article {1528,
	title = {Spontaneous emission by rotating objects: A scattering approach},
	journal = {Physical Review Letters},
	volume = {108},
	year = {2012},
	month = {2012/6/7},
	abstract = {  We study the quantum electrodynamics (QED) vacuum in the presence of a body
rotating along its axis of symmetry and show that the object spontaneously
emits energy if it is lossy. The radiated power is expressed as a general trace
formula solely in terms of the scattering matrix, making an explicit connection
to the conjecture of Zel{\textquoteright}dovich [JETP Lett. 14, 180 (1971)] on rotating
objects. We further show that a rotating body drags along nearby objects while
making them spin parallel to its own rotation axis.
},
	doi = {10.1103/PhysRevLett.108.230403},
	url = {http://arxiv.org/abs/1202.1485v2},
	author = {Mohammad F. Maghrebi and Robert L. Jaffe and Mehran Kardar}
}
@article {1531,
	title = {Casimir force between sharp-shaped conductors},
	journal = {Proceedings of the National Academy of Sciences},
	volume = {108},
	year = {2011},
	month = {2011/04/11},
	pages = {6867 - 6871},
	abstract = {  Casimir forces between conductors at the sub-micron scale cannot be ignored
in the design and operation of micro-electromechanical (MEM) devices. However,
these forces depend non-trivially on geometry, and existing formulae and
approximations cannot deal with realistic micro-machinery components with sharp
edges and tips. Here, we employ a novel approach to electromagnetic scattering,
appropriate to perfect conductors with sharp edges and tips, specifically to
wedges and cones. The interaction of these objects with a metal plate (and
among themselves) is then computed systematically by a multiple-scattering
series. For the wedge, we obtain analytical expressions for the interaction
with a plate, as functions of opening angle and tilt, which should provide a
particularly useful tool for the design of MEMs. Our result for the Casimir
interactions between conducting cones and plates applies directly to the force
on the tip of a scanning tunneling probe; the unexpectedly large temperature
dependence of the force in these configurations should attract immediate
experimental interest.
},
	doi = {10.1073/pnas.1018079108},
	url = {http://arxiv.org/abs/1010.3223v1},
	author = {Mohammad F. Maghrebi and Sahand Jamal Rahi and Thorsten Emig and Noah Graham and Robert L. Jaffe and Mehran Kardar}
}
@article {1521,
	title = {Entropic force of polymers on a cone tip},
	journal = {EPL (Europhysics Letters)},
	volume = {96},
	year = {2011},
	month = {2011/12/01},
	pages = {66002},
	abstract = {  We consider polymers attached to the tip of a cone, and the resulting force
due to entropy loss on approaching a plate (or another cone). At separations
shorter than the polymer radius of gyration R_g, the only relevant length scale
is the tip-plate (or tip-tip) separation h, and the entropic force is given by
F=A kT/h. The universal amplitude A can be related to (geometry dependent)
correlation exponents of long polymers. We compute A for phantom polymers, and
for self-avoiding (including star) polymers by epsilon-expansion, as well as by
numerical simulations in 3 dimensions.
},
	doi = {10.1209/0295-5075/96/66002},
	url = {http://arxiv.org/abs/1109.5658v2},
	author = {Mohammad F. Maghrebi and Yacov Kantor and Mehran Kardar}
}
