7,483 research outputs found
Discrimination and synthesis of recursive quantum states in high-dimensional Hilbert spaces
We propose an interferometric method for statistically discriminating between
nonorthogonal states in high dimensional Hilbert spaces for use in quantum
information processing. The method is illustrated for the case of photon
orbital angular momentum (OAM) states. These states belong to pairs of bases
that are mutually unbiased on a sequence of two-dimensional subspaces of the
full Hilbert space, but the vectors within the same basis are not necessarily
orthogonal to each other. Over multiple trials, this method allows
distinguishing OAM eigenstates from superpositions of multiple such
eigenstates. Variations of the same method are then shown to be capable of
preparing and detecting arbitrary linear combinations of states in Hilbert
space. One further variation allows the construction of chains of states
obeying recurrence relations on the Hilbert space itself, opening a new range
of possibilities for more abstract information-coding algorithms to be carried
out experimentally in a simple manner. Among other applications, we show that
this approach provides a simplified means of switching between pairs of
high-dimensional mutually unbiased OAM bases
Conformal Truncation of Chern-Simons Theory at Large
We set up and analyze the lightcone Hamiltonian for an abelian Chern-Simons
field coupled to fermions in the limit of large using conformal
truncation, i.e. with a truncated space of states corresponding to primary
operators with dimension below a maximum cutoff . In both the
Chern-Simons theory, and in the model at infinite , we compute the
current spectral functions analytically as a function of and
reproduce previous results in the limit that the truncation
is taken to . Along the way, we determine how to preserve gauge
invariance and how to choose an optimal discrete basis for the momenta of
states in the truncation space.Comment: 32+25 pages, 8 figures. v2: updated ref
Quantum simulation of topologically protected states using directionally unbiased linear-optical multiports
It is shown that quantum walks on one-dimensional arrays of special
linear-optical units allow the simulation of discrete-time Hamiltonian systems
with distinct topological phases. In particular, a slightly modified version of
the Su-Schrieffer-Heeger (SSH) system can be simulated, which exhibits states
of nonzero winding number and has topologically protected boundary states. In
the large-system limit this approach uses quadratically fewer resources to
carry out quantum simulations than previous linear-optical approaches and can
be readily generalized to higher-dimensional systems. The basic optical units
that implement this simulation consist of combinations of optical multiports
that allow photons to reverse direction
Quantum simulation of discrete-time Hamiltonians using directionally unbiased linear optical multiports
Recently, a generalization of the standard optical multiport was proposed [Phys. Rev. A 93, 043845 (2016)]. These directionally unbiased multiports allow photons to reverse direction and exit backwards from the input port, providing a realistic linear optical scattering vertex for quantum walks on arbitrary graph structures. Here, it is shown that arrays of these multiports allow the simulation of a range of discrete-time Hamiltonian systems. Examples are described, including a case where both spatial and internal degrees of freedom are simulated. Because input ports also double as output ports, there is substantial savings of resources compared to feed-forward networks carrying out the same functions. The simulation is implemented in a scalable manner using only linear optics, and can be generalized to higher dimensional systems in a straightforward fashion, thus offering a concrete experimentally achievable implementation of graphical models of discrete-time quantum systems.This research was supported by the National Science Foundation EFRI-ACQUIRE Grant No. ECCS-1640968, NSF Grant No. ECCS-1309209, and by the Northrop Grumman NG Next. (ECCS-1640968 - National Science Foundation EFRI-ACQUIRE Grant; ECCS-1309209 - NSF Grant; Northrop Grumman NG Next
Static Longitudinal Aerodynamic Characteristics of a 52 Degree Sweptback Wing of Aspect Ratio 2.88 at Reynolds Numbers from 2,000,000 to 11,000,000
Longitudinal-stability Investigation of High-lift and Stall-control Devices on a 52 Degree Sweptback Wing with and Without Fuselage and Horizontal Tail at a Reynolds Number of 6.8 x 10(exp 6).
Contains low-speed longitudinal stability characteristics of a 52 degree sweptback wing of aspect ratio 2.88, taper ratio 0.625, and NACA 64 (sub 1)-112 airfoil sections normal to the 0.282-chord line, in combination with split flaps, leading-edge flaps, and upper-surface fences. Low-wing and midwing-fuselage aerodynamic characteristics are presented with and without a horizontal tail at various vertical locations. Tests were conducted at a Reynolds number of 6.8 x 10(exp 6)
CFT and Lattice Correlators Near an RG Domain Wall between Minimal Models
Conformal interfaces separating two conformal field theories (CFTs) provide
maps between different CFTs, and naturally exist in nature as domain walls
between different phases. One particularly interesting construction of a
conformal interface is the renormalization group (RG) domain wall between CFTs.
For a given Virasoro minimal model , an RG domain wall
can be generated by a specific deformation which triggers an RG flow towards
its adjacent Virasoro minimal model with the
deformation turned on over part of the space. An algebraic construction of this
domain wall was proposed by Gaiotto in \cite{Gaiotto:2012np}. In this paper, we
will provide a study of this RG domain wall for the minimal case , which
can be thought of as a nonperturbative check of the construction. In this case
the wall is separating the Tricritical Ising Model (TIM) CFT and the Ising
Model (IM) CFT. We will check the analytical results of correlation functions
from the RG brane construction with the numerical density matrix
renormalization group (DMRG) calculation using a lattice model proposed in
\cite{Grover:2012bm,Grover:2013rc}, and find a perfect agreement. We comment on
possible experimental realizations of this RG domain wall.Comment: 24+19 pages, 11 figure
- …