34 research outputs found
The thermodynamics of creating correlations: Limitations and optimal protocols
We establish a rigorous connection between fundamental resource theories at
the quantum scale. Correlations and entanglement constitute indispensable
resources for numerous quantum information tasks. However, their establishment
comes at the cost of energy, the resource of thermodynamics, and is limited by
the initial entropy. Here, the optimal conversion of energy into correlations
is investigated. Assuming the presence of a thermal bath, we establish general
bounds for arbitrary systems and construct a protocol saturating them. The
amount of correlations, quantified by the mutual information, can increase at
most linearly with the available energy, and we determine where the linear
regime breaks down. We further consider the generation of genuine quantum
correlations, focusing on the fundamental constituents of our universe:
fermions and bosons. For fermionic modes, we find the optimal entangling
protocol. For bosonic modes, we show that while Gaussian operations can be
outperformed in creating entanglement, their performance is optimal for high
energies.Comment: 12 pages, 6 figure
Most energetic passive states
Passive states are defined as those states that do not allow for work
extraction in a cyclic (unitary) process. Within the set of passive states,
thermal states are the most stable ones: they maximize the entropy for a given
energy, and similarly they minimize the energy for a given entropy. Here we
find the passive states lying in the other extreme, i.e., those that maximize
the energy for a given entropy, which we show also minimize the entropy when
the energy is fixed. These extremal properties make these states useful to
obtain fundamental bounds for the thermodynamics of finite-dimensional quantum
systems, which we show in several scenarios.Comment: 6 pages, 2 figures; published versio