Shortcut to adiabaticity in spinor condensates

Abstract

We devise a method to shortcut the adiabatic evolution of a spin-1 Bose gas with an external magnetic field as the control parameter. An initial many-body state with almost all bosons populating the Zeeman sublevel m = 0, is evolved to a final state very close to a macroscopic spin-singlet condensate, a fragmented state with three macroscopically occupied Zeeman states. The shortcut protocol, obtained by an approximate mapping to a harmonic oscillator Hamiltonian, is compared to linear and exponential variations of the control parameter. We find a dramatic speedup of the dynamics when using the shortcut protocol.

Supersensitive quantum sensor based on criticality in an antiferromagnetic spinor condensate

“…For the experimental realization of our protocol, one possibility is to perform the adiabatic ramp of the ground state of the system followed by measuring the population of the atoms in m f = 0 Zeeman energy level, namelyN 0 . The viability of these methods is connected to the energy gap ∆ as it determines the adiabatic evolution time τ according to the adiabatic criterion | e|Ḣ|g | ≪ ∆ 2 [50,57], where |g and |e are the ground and excited states of the Hamiltonian (1), respectively. In the case of zero magnetization, the minimum of the energy gap between the ground and first excited state is ∼ N −1 , while on the other hand e|Ḣ|g ∼ N/(3τ ) considering N 0 = N/3 and a linear change in time of the parameter q.…”

“…This gives τ ≫ N 3 /27, which restricts the possibility of performing the adiabatic evolution of the ground state to relatively small systems. In the case of larger systems, it might be possible to use other methods, such as shortcut to adiabaticity discussed in [50]. On the other hand, in the case of macroscopic magnetization, the process of adiabatic sweeping of q is easier to be implemented due to the wider energy gap which scales as N −1/3 .…”

“…Moreover, the scaling exponent of the energy gap is the same as that for a ferromagnetic spinor condensate [20], the Lipkin-Meshkov-Glick [49], bosonic Josephson junction [8] and the interacting Dicke [48] models. In the case of zero magnetization the energy gap minimum scales as N −1 [15,50,51]. Although the universal behavior cannot be expressed in terms of critical exponents, it indeed can be observed 7(b) with the scaling of the energy gap minimum as ∆ min = 2.83N −1 .…”

Novel concept for a neutron electric charge measurement using a Talbot-Lau interferometer at a pulsed source

“…searching for a non-zero neutron electric charge, performing ultra small angle scattering measurements, and investigating the deflection of neutrons due to gravitational interaction with macroscopic test masses [51,52]. Theoretical calculations and simulations of such kind of grating interferometers are described in detail in [53,54]. Here, the concept of a meter-long symmetric neutron Talbot-Lau interferometer operated in time-offlight mode is presented.…”

Quantum state transfer in spin chains via shortcuts to adiabaticity

“…The core of the STA is to drive the system following a relatively rapid adiabatic-like process which is not really adiabatic but leading to the same goals as the adiabatic process does. With several advantages, the STA has attracted a lot of interests [43][44][45][46][47][48][49][50][51] and been applied in fields including fast population transfer [52][53][54], fast entanglement generation [55][56][57], fast quantum computation [58], and so on [59][60][61][62][63][64]. Experimental implementations of this technique have also been reported [54,[65][66][67].…”