Hi all,
Tomorrow David Ittah will tell us about his master thesis on "Multi-level
IR for Quantum Program Optimization", which was supervised by Torsten
Hoefler from the CS department and Thomas Häner from Microsoft (formerly
Troyer group). See below for the abstract. The zoom link is
https://ethz.zoom.us/j/362994444.
Best,
Joe
Abstract:
Intermediate representations (IR) have traditionally provided numerous
benefits to compilation systems, in particular in the domain of static
program analysis and optimization. However, the quantum programming
landscape has yet to produce similarly powerful IRs, instead focusing on
the development of embedded domain-specific languages (eDSL). As these only
feature rudimentary IRs in the form of data structures for quantum
circuits, or simple quantum assembly (QASM) languages, they lack meaningful
integration with their classical host compilation infrastructure. As a
remedy, we propose a novel quantum IR design based on exposing SSA-like
quantum dataflow in the IR alongside classical dataflow. Our language- and
hardware-agnostic IR is designed to enable classical-quantum
co-optimization, and with the intent to maximize the reuse of existing
compilation infrastructure. An implementation in the MLIR compiler
framework demonstrates that ∼99.8% of savings identified by ProjectQ’s
run-time optimizations on Shor’s algorithm can be exploited by static
optimizations in our IR. A resource estimation routine to count the number
of rotation gates in Shor’s algorithm is shown to run 5-6 orders of
magnitudes faster on application-scale input sizes than on existing systems
in ProjectQ and Qiskit.
Hi all,
Tomorrow at 2pm Severin Meng will tell us about his master thesis, entitled
"Thermodynamic Properties of Passive States". See below for the abstract.
The meeting link is https://ethz.zoom.us/j/362994444.
Best,
Joe
Abstract:
A passive state is defined such that no unitary transformation can lower
its average energy. Within the set of passive states one finds the
well-known thermal states, which are described by a quantum analogue of
classical temperature. Interesting quantities like the efficiency, cooling
performance or even possibility of a state transition within settings that
use a thermal state resource are characterised by the state's temperature
and Hamiltonian.
Non-thermal passive states appear naturally, for example at the end of a
thermodynamic process like cooling, and they may thus be used as an initial
state in a different thermodynamic scenario. There is no unique temperature
of a non-thermal passive state that characterises its thermodynamic
performance. We investigate which properties of passive states determine
their thermodynamic behaviour. We approach this task by exploring different
thermodynamic settings that involve passive states. The considered settings
include an autonomous heat engine and refrigerator as well as state
transformations and more abstract work extraction protocols.
We find different parameters for the various scenarios that describe the
thermodynamics of the passive state. The set of relevant parameters
includes the temperatures of the thermal state of the same energy as well
as the thermal state of the same entropy, the asymptotic activation energy,
the free energy and entropy as well as specific combinations of energy gaps
and virtual temperatures within the passive state.
Hi all,
Tomorrow Henrik will kick off the QIT Seminar in the new year. He will tell
us about the connection between entropy and reversible catalysis, from
arXiv:2012.05573 <https://arxiv.org/abs/2012.05573> . The talk starts at
2pm on zoom: https://ethz.zoom.us/j/362994444.
Best,
Joe