Time crystals in periodically driven systems have initially been studied
assuming the ability to quench the Hamiltonian between different many-body
regimes and/or the presence of disorder or long-range interactions. Here we
propose a scheme to observe discrete time crystal dynamics in a clean driven
quantum system of the Ising type with short range interactions. The system is
subject only to a periodic kick by a global magnetic field and no extra
Hamiltonian quenching is performed. We analyse the emerging time crystal

We present a modular design for integrated programmable multimode sources of
arbitrary Gaussian states of light. The technique is based on current
technologies, in particular recent demonstrations of on-chip photon
manipulation and generation of highly squeezed vacuum states in semiconductors.
While the design is generic and independent of the choice of integrated
platform, we adopt recent experimental results on compound semiconductors as a
demonstrative example. Such a device would be valuable as a source for many

We study quantum communication protocols, in which the players' storage
starts out in a state where one qubit is in a pure state, and all other qubits
are totally mixed (i.e. in a random state), and no other storage is available
(for messages or internal computations). This restriction on the available
quantum memory has been studied extensively in the model of quantum circuits,
and it is known that classically simulating quantum circuits operating on such

We study the effect of correlated Markovian noise channels on the quantum
speed limit of an open system. This is done for correlated dephasing and
amplitude damping channels for a two qubit atomic model. Our model serves as a
platform for a detailed study of speed of quantum evolution in correlated open

We present and test a new algorithm for time-evolving quantum many-body
systems initially proposed by Holzner et al. [Phys. Rev. B 83, 195115 (2011)].
The approach is based on merging the matrix product state (MPS) formalism with
the method of expanding the time-evolution operator in Chebyshev polynomials.
We calculate time-dependent observables of a system of hardcore bosons quenched
under the Bose-Hubbard Hamiltonian on a one-dimensional lattice. We compare the

Arnoldi method and conjugate gradient method are important classical
iteration methods in solving linear systems and estimating eigenvalues. Their
efficiency often affected by the high dimension of the space, where quantum
computer can play a role in. In this work, we establish their corresponding
quantum algorithms. To achieve high efficiency, a new method about linear
combination of quantum states will be proposed. The final complexity of quantum
Arnoldi iteration method is $O(m^{4+\log m/\epsilon}(\log n)^2

Thermodynamics can be formulated in either of two approaches, the
phenomenological approach, which refers to the macroscopic properties of
systems, and the statistical approach, which describes systems in terms of
their microscopic constituents. We establish a connection between these two
approaches by means of a new axiomatic framework that can take errors and
imprecisions into account. This link extends to systems of arbitrary sizes
including microscopic systems, for which the treatment of imprecisions is

A tripartite quantum network is said to be bilocal if two independent sources
produce a pair of bipartite entangled states. Quantum non-bilocal correlation
emerges when the central party which possesses two particles from two different
sources performs Bell-state measurement on them and nonlocality is generated
between the other two uncorrelated systems in this entanglement-swapping
protocol. The interaction of such systems with the environment reduces quantum

We study the dissipative propagation of quantized light in interacting
Rydberg media under the conditions of electromagnetically induced transparency
(EIT). Rydberg blockade physics in optically dense atomic media leads to strong
dissipative interactions between single photons. The regime of high incoming
photon flux constitutes a challenging many-body dissipative problem. We
experimentally study in detail for the first time the pulse shapes and the
second-order correlation function of the outgoing field and compare our data

The uncertainty principle, a jewel at the heart of quantum theory, has been
expressed by completely different forms, such as universal uncertainty
relations, an uncertainty principle in the presence of quantum memory and a
fine-grained uncertainty relation. We unify these uncertainty relations based
on a special formalization of probability relations, namely introducing
quasi-fine-grained uncertainty relations (QFGURs), which combine different
measurements performed on spacelike-separated systems. Our generalized