A Complexity Theory for the Quantum Age?
How hard is it to compress a quantum state? To fast-forward the evolution of a local Hamiltonian? To unscramble the Hawking radiation of a black hole? Traditional complexity theory -- which is centered around decision problems and tasks with classical inputs and outputs -- appears inadequate for reasoning about the complexity of such tasks involving quantum inputs and outputs.
Multi-qubit gates for quantum computing with neutral atoms
Neutral atoms have emerged as a competitive platform for digital quantum simulations and computing. In this talk, we discuss recent results on the design of time-optimal and robust multi-qubit gates for neutral atoms. We present a family of Rydberg blockade gates that are robust against two common experimental imperfections -- intensity inhomogeneity and Doppler shifts – and demonstrate that these gates outperform existing gates for moderate or large imperfections.
Crystal Imperfections Reveal Rich New Phases of Familiar Matter
Matter is often classified into familiar phases: solid, liquid, and gas. But the traits that define those phases are not the only properties of matter that matter. Sometimes physicists use other paradigms, like mathematically defined topological traits. Theorists at JQI have revealed a host of possible topological phases that become apparent when two different kinds of defects develop in crystals, or when they study the twirling properties of the electronic arrangement.
Yunger Halpern Is US Nominee for ASPIRE Young Researcher Award
JQI affiliate Nicole Yunger Halpern received an annual prize for young researchers from the APEC trade organization. Yunger Halpern’s nomination by the State Department’s Office of Science and Technology Cooperation comes with its own $3,000 prize.
Controllability of quantum dot arrays via maximum entropy
Quantum dots are a promising platform to realize practical quantum computing. However, before they can be used as qubits, quantum dots must be carefully tuned to the correct regime in the voltage space to trap individual electrons. Moreover, realizable quantum computing requires tuning of large arrays, which translates to a significant increase in the number of parameters that need to be controlled and calibrated. This necessitates the development of robust and automated methods to bring the device into an operational state.
Quantum simulations with trapped ions: Thermal \lamba\phi^4 field theories and Z2 gauge theories
In this talk, Dr Bermúdez will start by reviewing the recent progress of analog quantum simulators based on crystals of trapped atomic ions. He will discuss recent experiments that exploit both the electronic and vibrational degrees of freedom to simulate spin models and bosonic lattice models.
Quantum Communication and Thermalization, From Theory to Practice
The postulates of quantum mechanics generalize classical probability distributions and thus transmission of information, enabling fundamentally novel protocols for communication and cryptography. These algorithms motivate the deployment of quantum networks, a distributed model of computation where universality and fault-tolerance are often not required. Based on constructions from communication complexity, we design a voting scheme with efficient scaling of quantum communication and computation, and prove its security.